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Package validator implements value validations for structs and individual fields based on tags. It can also handle Cross-Field and Cross-Struct validation for nested structs and has the ability to dive into arrays and maps of any type. see more examples https://github.com/go-playground/validator/tree/v9/_examples Doing things this way is actually the way the standard library does, see the file.Open method here: The authors return type "error" to avoid the issue discussed in the following, where err is always != nil: Validator only InvalidValidationError for bad validation input, nil or ValidationErrors as type error; so, in your code all you need to do is check if the error returned is not nil, and if it's not check if error is InvalidValidationError ( if necessary, most of the time it isn't ) type cast it to type ValidationErrors like so err.(validator.ValidationErrors). Custom Validation functions can be added. Example: Cross-Field Validation can be done via the following tags: If, however, some custom cross-field validation is required, it can be done using a custom validation. Why not just have cross-fields validation tags (i.e. only eqcsfield and not eqfield)? The reason is efficiency. If you want to check a field within the same struct "eqfield" only has to find the field on the same struct (1 level). But, if we used "eqcsfield" it could be multiple levels down. Example: Multiple validators on a field will process in the order defined. Example: Bad Validator definitions are not handled by the library. Example: Baked In Cross-Field validation only compares fields on the same struct. If Cross-Field + Cross-Struct validation is needed you should implement your own custom validator. Comma (",") is the default separator of validation tags. If you wish to have a comma included within the parameter (i.e. excludesall=,) you will need to use the UTF-8 hex representation 0x2C, which is replaced in the code as a comma, so the above will become excludesall=0x2C. Pipe ("|") is the 'or' validation tags deparator. If you wish to have a pipe included within the parameter i.e. excludesall=| you will need to use the UTF-8 hex representation 0x7C, which is replaced in the code as a pipe, so the above will become excludesall=0x7C Here is a list of the current built in validators: Tells the validation to skip this struct field; this is particularly handy in ignoring embedded structs from being validated. (Usage: -) This is the 'or' operator allowing multiple validators to be used and accepted. (Usage: rbg|rgba) <-- this would allow either rgb or rgba colors to be accepted. This can also be combined with 'and' for example ( Usage: omitempty,rgb|rgba) When a field that is a nested struct is encountered, and contains this flag any validation on the nested struct will be run, but none of the nested struct fields will be validated. This is useful if inside of your program you know the struct will be valid, but need to verify it has been assigned. NOTE: only "required" and "omitempty" can be used on a struct itself. Same as structonly tag except that any struct level validations will not run. Allows conditional validation, for example if a field is not set with a value (Determined by the "required" validator) then other validation such as min or max won't run, but if a value is set validation will run. This tells the validator to dive into a slice, array or map and validate that level of the slice, array or map with the validation tags that follow. Multidimensional nesting is also supported, each level you wish to dive will require another dive tag. dive has some sub-tags, 'keys' & 'endkeys', please see the Keys & EndKeys section just below. Example #1 Example #2 Keys & EndKeys These are to be used together directly after the dive tag and tells the validator that anything between 'keys' and 'endkeys' applies to the keys of a map and not the values; think of it like the 'dive' tag, but for map keys instead of values. Multidimensional nesting is also supported, each level you wish to validate will require another 'keys' and 'endkeys' tag. These tags are only valid for maps. Example #1 Example #2 This validates that the value is not the data types default zero value. For numbers ensures value is not zero. For strings ensures value is not "". For slices, maps, pointers, interfaces, channels and functions ensures the value is not nil. The field under validation must be present and not empty only if any of the other specified fields are present. For strings ensures value is not "". For slices, maps, pointers, interfaces, channels and functions ensures the value is not nil. Examples: The field under validation must be present and not empty only if all of the other specified fields are present. For strings ensures value is not "". For slices, maps, pointers, interfaces, channels and functions ensures the value is not nil. Example: The field under validation must be present and not empty only when any of the other specified fields are not present. For strings ensures value is not "". For slices, maps, pointers, interfaces, channels and functions ensures the value is not nil. Examples: The field under validation must be present and not empty only when all of the other specified fields are not present. For strings ensures value is not "". For slices, maps, pointers, interfaces, channels and functions ensures the value is not nil. Example: This validates that the value is the default value and is almost the opposite of required. For numbers, length will ensure that the value is equal to the parameter given. For strings, it checks that the string length is exactly that number of characters. For slices, arrays, and maps, validates the number of items. For numbers, max will ensure that the value is less than or equal to the parameter given. For strings, it checks that the string length is at most that number of characters. For slices, arrays, and maps, validates the number of items. For numbers, min will ensure that the value is greater or equal to the parameter given. For strings, it checks that the string length is at least that number of characters. For slices, arrays, and maps, validates the number of items. For strings & numbers, eq will ensure that the value is equal to the parameter given. For slices, arrays, and maps, validates the number of items. For strings & numbers, ne will ensure that the value is not equal to the parameter given. For slices, arrays, and maps, validates the number of items. For strings, ints, and uints, oneof will ensure that the value is one of the values in the parameter. The parameter should be a list of values separated by whitespace. Values may be strings or numbers. For numbers, this will ensure that the value is greater than the parameter given. For strings, it checks that the string length is greater than that number of characters. For slices, arrays and maps it validates the number of items. Example #1 Example #2 (time.Time) For time.Time ensures the time value is greater than time.Now.UTC(). Same as 'min' above. Kept both to make terminology with 'len' easier. Example #1 Example #2 (time.Time) For time.Time ensures the time value is greater than or equal to time.Now.UTC(). For numbers, this will ensure that the value is less than the parameter given. For strings, it checks that the string length is less than that number of characters. For slices, arrays, and maps it validates the number of items. Example #1 Example #2 (time.Time) For time.Time ensures the time value is less than time.Now.UTC(). Same as 'max' above. Kept both to make terminology with 'len' easier. Example #1 Example #2 (time.Time) For time.Time ensures the time value is less than or equal to time.Now.UTC(). This will validate the field value against another fields value either within a struct or passed in field. Example #1: Example #2: Field Equals Another Field (relative) This does the same as eqfield except that it validates the field provided relative to the top level struct. This will validate the field value against another fields value either within a struct or passed in field. Examples: Field Does Not Equal Another Field (relative) This does the same as nefield except that it validates the field provided relative to the top level struct. Only valid for Numbers and time.Time types, this will validate the field value against another fields value either within a struct or passed in field. usage examples are for validation of a Start and End date: Example #1: Example #2: This does the same as gtfield except that it validates the field provided relative to the top level struct. Only valid for Numbers and time.Time types, this will validate the field value against another fields value either within a struct or passed in field. usage examples are for validation of a Start and End date: Example #1: Example #2: This does the same as gtefield except that it validates the field provided relative to the top level struct. Only valid for Numbers and time.Time types, this will validate the field value against another fields value either within a struct or passed in field. usage examples are for validation of a Start and End date: Example #1: Example #2: This does the same as ltfield except that it validates the field provided relative to the top level struct. Only valid for Numbers and time.Time types, this will validate the field value against another fields value either within a struct or passed in field. usage examples are for validation of a Start and End date: Example #1: Example #2: This does the same as ltefield except that it validates the field provided relative to the top level struct. This does the same as contains except for struct fields. It should only be used with string types. See the behavior of reflect.Value.String() for behavior on other types. This does the same as excludes except for struct fields. It should only be used with string types. See the behavior of reflect.Value.String() for behavior on other types. For arrays & slices, unique will ensure that there are no duplicates. For maps, unique will ensure that there are no duplicate values. For slices of struct, unique will ensure that there are no duplicate values in a field of the struct specified via a parameter. This validates that a string value contains ASCII alpha characters only This validates that a string value contains ASCII alphanumeric characters only This validates that a string value contains unicode alpha characters only This validates that a string value contains unicode alphanumeric characters only This validates that a string value contains a basic numeric value. basic excludes exponents etc... for integers or float it returns true. This validates that a string value contains a valid hexadecimal. This validates that a string value contains a valid hex color including hashtag (#) This validates that a string value contains a valid rgb color This validates that a string value contains a valid rgba color This validates that a string value contains a valid hsl color This validates that a string value contains a valid hsla color This validates that a string value contains a valid email This may not conform to all possibilities of any rfc standard, but neither does any email provider accept all possibilities. This validates that a string value contains a valid file path and that the file exists on the machine. This is done using os.Stat, which is a platform independent function. This validates that a string value contains a valid url This will accept any url the golang request uri accepts but must contain a schema for example http:// or rtmp:// This validates that a string value contains a valid uri This will accept any uri the golang request uri accepts This validataes that a string value contains a valid URN according to the RFC 2141 spec. This validates that a string value contains a valid base64 value. Although an empty string is valid base64 this will report an empty string as an error, if you wish to accept an empty string as valid you can use this with the omitempty tag. This validates that a string value contains a valid base64 URL safe value according the the RFC4648 spec. Although an empty string is a valid base64 URL safe value, this will report an empty string as an error, if you wish to accept an empty string as valid you can use this with the omitempty tag. This validates that a string value contains a valid bitcoin address. The format of the string is checked to ensure it matches one of the three formats P2PKH, P2SH and performs checksum validation. Bitcoin Bech32 Address (segwit) This validates that a string value contains a valid bitcoin Bech32 address as defined by bip-0173 (https://github.com/bitcoin/bips/blob/master/bip-0173.mediawiki) Special thanks to Pieter Wuille for providng reference implementations. This validates that a string value contains a valid ethereum address. The format of the string is checked to ensure it matches the standard Ethereum address format Full validation is blocked by https://github.com/golang/crypto/pull/28 This validates that a string value contains the substring value. This validates that a string value contains any Unicode code points in the substring value. This validates that a string value contains the supplied rune value. This validates that a string value does not contain the substring value. This validates that a string value does not contain any Unicode code points in the substring value. This validates that a string value does not contain the supplied rune value. This validates that a string value starts with the supplied string value This validates that a string value ends with the supplied string value This validates that a string value contains a valid isbn10 or isbn13 value. This validates that a string value contains a valid isbn10 value. This validates that a string value contains a valid isbn13 value. This validates that a string value contains a valid UUID. Uppercase UUID values will not pass - use `uuid_rfc4122` instead. This validates that a string value contains a valid version 3 UUID. Uppercase UUID values will not pass - use `uuid3_rfc4122` instead. This validates that a string value contains a valid version 4 UUID. Uppercase UUID values will not pass - use `uuid4_rfc4122` instead. This validates that a string value contains a valid version 5 UUID. Uppercase UUID values will not pass - use `uuid5_rfc4122` instead. This validates that a string value contains only ASCII characters. NOTE: if the string is blank, this validates as true. This validates that a string value contains only printable ASCII characters. NOTE: if the string is blank, this validates as true. This validates that a string value contains one or more multibyte characters. NOTE: if the string is blank, this validates as true. This validates that a string value contains a valid DataURI. NOTE: this will also validate that the data portion is valid base64 This validates that a string value contains a valid latitude. This validates that a string value contains a valid longitude. This validates that a string value contains a valid U.S. Social Security Number. This validates that a string value contains a valid IP Address. This validates that a string value contains a valid v4 IP Address. This validates that a string value contains a valid v6 IP Address. This validates that a string value contains a valid CIDR Address. This validates that a string value contains a valid v4 CIDR Address. This validates that a string value contains a valid v6 CIDR Address. This validates that a string value contains a valid resolvable TCP Address. This validates that a string value contains a valid resolvable v4 TCP Address. This validates that a string value contains a valid resolvable v6 TCP Address. This validates that a string value contains a valid resolvable UDP Address. This validates that a string value contains a valid resolvable v4 UDP Address. This validates that a string value contains a valid resolvable v6 UDP Address. This validates that a string value contains a valid resolvable IP Address. This validates that a string value contains a valid resolvable v4 IP Address. This validates that a string value contains a valid resolvable v6 IP Address. This validates that a string value contains a valid Unix Address. This validates that a string value contains a valid MAC Address. Note: See Go's ParseMAC for accepted formats and types: This validates that a string value is a valid Hostname according to RFC 952 https://tools.ietf.org/html/rfc952 This validates that a string value is a valid Hostname according to RFC 1123 https://tools.ietf.org/html/rfc1123 Full Qualified Domain Name (FQDN) This validates that a string value contains a valid FQDN. This validates that a string value appears to be an HTML element tag including those described at https://developer.mozilla.org/en-US/docs/Web/HTML/Element This validates that a string value is a proper character reference in decimal or hexadecimal format This validates that a string value is percent-encoded (URL encoded) according to https://tools.ietf.org/html/rfc3986#section-2.1 This validates that a string value contains a valid directory and that it exists on the machine. This is done using os.Stat, which is a platform independent function. NOTE: When returning an error, the tag returned in "FieldError" will be the alias tag unless the dive tag is part of the alias. Everything after the dive tag is not reported as the alias tag. Also, the "ActualTag" in the before case will be the actual tag within the alias that failed. Here is a list of the current built in alias tags: Validator notes: A collection of validation rules that are frequently needed but are more complex than the ones found in the baked in validators. A non standard validator must be registered manually like you would with your own custom validation functions. Example of registration and use: Here is a list of the current non standard validators: This package panics when bad input is provided, this is by design, bad code like that should not make it to production.

Package psx provides support for system calls that are run simultaneously on all threads under Linux. It supports tool chains after go1.16. Earlier toolchains had no reliable way to support this because of Bug 219478. The package works differently depending on whether or not CGO_ENABLED is 0 or 1. In the former case, psx is a low overhead wrapper for the two native go calls: syscall.AllThreadsSyscall() and syscall.AllThreadsSyscall6() introduced in go1.16. We provide this package wrapping to minimize client source code changes when compiling with or without CGo enabled. In the latter case it works via CGo wrappers for system call functions that call the C [lib]psx functions of these names. This ensures that the system calls execute simultaneously on all the threads of the Go (and CGo) combined runtime. With CGo, the psx support works in the following way: the thread that is first asked to execute the syscall does so, and determines if it succeeds or fails. If it fails, it returns immediately without attempting the syscall on other threads. If the initial attempt succeeds, however, then the runtime is stopped in order for the same system call to be performed on all the remaining threads of the runtime. Once all threads have completed the syscall, the return codes are those obtained by the first thread's invocation of the syscall. Note, there is no need to use this variant of syscall where the syscalls only read state from the kernel. However, since Go's runtime freely migrates code execution between threads, support of this type is required for any successful attempt to fully drop or modify the privilege of a running Go program under Linux. More info on how Linux privilege works and examples of using this package can be found on the Fully Capable site. WARNING: For older go toolchains (prior to go1.16), the code should mostly work as far back as go1.11. However, like support for C.setuid(), this support is fragile and may hang. See the above bug for details. Copyright (c) 2019,20,24 Andrew G. Morgan <morgan@kernel.org> The psx package is licensed with a (you choose) BSD 3-clause or GPL2. See LICENSE file for details.

Package toml implements decoding and encoding of TOML files. This package supports TOML v1.0.0, as specified at https://toml.io The github.com/BurntSushi/toml/cmd/tomlv package implements a TOML validator, and can be used to verify if TOML document is valid. It can also be used to print the type of each key. Example StrictDecoding shows how to detect if there are keys in the TOML document that weren't decoded into the value given. This is useful for returning an error to the user if they've included extraneous fields in their configuration. Example UnmarshalTOML shows how to implement a struct type that knows how to unmarshal itself. The struct must take full responsibility for mapping the values passed into the struct. The method may be used with interfaces in a struct in cases where the actual type is not known until the data is examined. Example Unmarshaler shows how to decode TOML strings into your own custom data type.

Package excelize providing a set of functions that allow you to write to and read from XLSX files. Support reads and writes XLSX file generated by Microsoft Excel™ 2007 and later. Support save file without losing original charts of XLSX. This library needs Go version 1.8 or later. See https://xuri.me/excelize for more information about this package.

This executable provides an HTTP server that watches for file system changes to .go files within the working directory (and all nested go packages). Navigating to the configured host and port in a web browser will display the latest results of running `go test` in each go package.

Package swagger (2.0) provides a powerful interface to your API Contains an implementation of Swagger 2.0. It knows how to serialize, deserialize and validate swagger specifications. Swagger is a simple yet powerful representation of your RESTful API. With the largest ecosystem of API tooling on the planet, thousands of developers are supporting Swagger in almost every modern programming language and deployment environment. With a Swagger-enabled API, you get interactive documentation, client SDK generation and discoverability. We created Swagger to help fulfill the promise of APIs. Swagger helps companies like Apigee, Getty Images, Intuit, LivingSocial, McKesson, Microsoft, Morningstar, and PayPal build the best possible services with RESTful APIs.Now in version 2.0, Swagger is more enabling than ever. And it's 100% open source software. More detailed documentation is available at https://goswagger.io. Install: The implementation also provides a number of command line tools to help working with swagger. Currently there is a spec validator tool: To generate a server for a swagger spec document: To generate a client for a swagger spec document: To generate a swagger spec document for a go application: There are several other sub commands available for the generate command You're free to add files to the directories the generated code lands in, but the files generated by the generator itself will be regenerated on following generation runs so any changes to those files will be lost. However extra files you create won't be lost so they are safe to use for customizing the application to your needs. To generate a server for a swagger spec document:

Package excelize providing a set of functions that allow you to write to and read from XLAM / XLSM / XLSX / XLTM / XLTX files. Supports reading and writing spreadsheet documents generated by Microsoft Excel™ 2007 and later. Supports complex components by high compatibility, and provided streaming API for generating or reading data from a worksheet with huge amounts of data. This library needs Go version 1.18 or later. See https://xuri.me/excelize for more information about this package.

Package cap provides all the Linux Capabilities userspace library API bindings in native Go. Capabilities are a feature of the Linux kernel that allow fine grain permissions to perform privileged operations. Privileged operations are required to do irregular system level operations from code. You can read more about how Capabilities are intended to work in this Linux Symposium paper. This package supports native Go bindings for all the features described in that paper as well as supporting subsequent changes to the kernel for other styles of inheritable Capability. Some simple things you can do with this package are: This `"cap"` package operates with POSIX semantics for security state. That is all OS threads are kept in sync at all times. The package `"kernel.org/pub/linux/libs/security/libcap/psx"` is used to implement POSIX semantics system calls that manipulate thread state uniformly over the whole Go (and any CGo linked) process runtime. Note, if the Go runtime syscall interface contains the Linux variant `syscall.AllThreadsSyscall()` API (it debuted in go1.16 see Go bug 1435 for its history) then the "libcap/psx" package will use that to invoke Capability setting system calls in pure Go binaries. With such an enhanced Go runtime, to force this behavior, use the CGO_ENABLED=0 environment variable. POSIX semantics are more secure than trying to manage privilege at a thread level when those threads share a common memory image as they do under Linux: it is trivial to exploit a vulnerability in one thread of a process to cause execution on any another thread. So, any imbalance in security state, in such cases will readily create an opportunity for a privilege escalation vulnerability. POSIX semantics also work well with Go, which deliberately tries to insulate the user from worrying about the number of OS threads that are actually running in their program. Indeed, Go can efficiently launch and manage tens of thousands of concurrent goroutines without bogging the program or wider system down. It does this by aggressively migrating idle threads to make progress on unblocked goroutines. So, inconsistent security state across OS threads can also lead to program misbehavior. The only exception to this process-wide common security state is the cap.Launcher related functionality. This briefly locks an OS thread to a goroutine in order to launch another executable - the robust implementation of this kind of support is quite subtle, so please read its documentation carefully, if you find that you need it. See the Fully Capable site for recent updates, some more complete walk-through examples of ways of using 'cap.Set's etc and information on how to file bugs. Copyright (c) 2019-21 Andrew G. Morgan <morgan@kernel.org> The cap and psx packages are licensed with a (you choose) BSD 3-clause or GPL2. See LICENSE file for details.

Package gofpdf implements a PDF document generator with high level support for text, drawing and images. - UTF-8 support - Choice of measurement unit, page format and margins - Page header and footer management - Automatic page breaks, line breaks, and text justification - Inclusion of JPEG, PNG, GIF, TIFF and basic path-only SVG images - Colors, gradients and alpha channel transparency - Outline bookmarks - Internal and external links - TrueType, Type1 and encoding support - Page compression - Lines, Bézier curves, arcs, and ellipses - Rotation, scaling, skewing, translation, and mirroring - Clipping - Document protection - Layers - Templates - Barcodes - Charting facility - Import PDFs as templates gofpdf has no dependencies other than the Go standard library. All tests pass on Linux, Mac and Windows platforms. gofpdf supports UTF-8 TrueType fonts and “right-to-left” languages. Note that Chinese, Japanese, and Korean characters may not be included in many general purpose fonts. For these languages, a specialized font (for example, NotoSansSC for simplified Chinese) can be used. Also, support is provided to automatically translate UTF-8 runes to code page encodings for languages that have fewer than 256 glyphs. This repository will not be maintained, at least for some unknown duration. But it is hoped that gofpdf has a bright future in the open source world. Due to Go’s promise of compatibility, gofpdf should continue to function without modification for a longer time than would be the case with many other languages. Forks should be based on the last viable commit. Tools such as active-forks can be used to select a fork that looks promising for your needs. If a particular fork looks like it has taken the lead in attracting followers, this README will be updated to point people in that direction. The efforts of all contributors to this project have been deeply appreciated. Best wishes to all of you. To install the package on your system, run Later, to receive updates, run The following Go code generates a simple PDF file. See the functions in the fpdf_test.go file (shown as examples in this documentation) for more advanced PDF examples. If an error occurs in an Fpdf method, an internal error field is set. After this occurs, Fpdf method calls typically return without performing any operations and the error state is retained. This error management scheme facilitates PDF generation since individual method calls do not need to be examined for failure; it is generally sufficient to wait until after Output() is called. For the same reason, if an error occurs in the calling application during PDF generation, it may be desirable for the application to transfer the error to the Fpdf instance by calling the SetError() method or the SetErrorf() method. At any time during the life cycle of the Fpdf instance, the error state can be determined with a call to Ok() or Err(). The error itself can be retrieved with a call to Error(). This package is a relatively straightforward translation from the original FPDF library written in PHP (despite the caveat in the introduction to Effective Go). The API names have been retained even though the Go idiom would suggest otherwise (for example, pdf.GetX() is used rather than simply pdf.X()). The similarity of the two libraries makes the original FPDF website a good source of information. It includes a forum and FAQ. However, some internal changes have been made. Page content is built up using buffers (of type bytes.Buffer) rather than repeated string concatenation. Errors are handled as explained above rather than panicking. Output is generated through an interface of type io.Writer or io.WriteCloser. A number of the original PHP methods behave differently based on the type of the arguments that are passed to them; in these cases additional methods have been exported to provide similar functionality. Font definition files are produced in JSON rather than PHP. A side effect of running go test ./... is the production of a number of example PDFs. These can be found in the gofpdf/pdf directory after the tests complete. Please note that these examples run in the context of a test. In order run an example as a standalone application, you’ll need to examine fpdf_test.go for some helper routines, for example exampleFilename() and summary(). Example PDFs can be compared with reference copies in order to verify that they have been generated as expected. This comparison will be performed if a PDF with the same name as the example PDF is placed in the gofpdf/pdf/reference directory and if the third argument to ComparePDFFiles() in internal/example/example.go is true. (By default it is false.) The routine that summarizes an example will look for this file and, if found, will call ComparePDFFiles() to check the example PDF for equality with its reference PDF. If differences exist between the two files they will be printed to standard output and the test will fail. If the reference file is missing, the comparison is considered to succeed. In order to successfully compare two PDFs, the placement of internal resources must be consistent and the internal creation timestamps must be the same. To do this, the methods SetCatalogSort() and SetCreationDate() need to be called for both files. This is done automatically for all examples. Nothing special is required to use the standard PDF fonts (courier, helvetica, times, zapfdingbats) in your documents other than calling SetFont(). You should use AddUTF8Font() or AddUTF8FontFromBytes() to add a TrueType UTF-8 encoded font. Use RTL() and LTR() methods switch between “right-to-left” and “left-to-right” mode. In order to use a different non-UTF-8 TrueType or Type1 font, you will need to generate a font definition file and, if the font will be embedded into PDFs, a compressed version of the font file. This is done by calling the MakeFont function or using the included makefont command line utility. To create the utility, cd into the makefont subdirectory and run “go build”. This will produce a standalone executable named makefont. Select the appropriate encoding file from the font subdirectory and run the command as in the following example. In your PDF generation code, call AddFont() to load the font and, as with the standard fonts, SetFont() to begin using it. Most examples, including the package example, demonstrate this method. Good sources of free, open-source fonts include Google Fonts and DejaVu Fonts. The draw2d package is a two dimensional vector graphics library that can generate output in different forms. It uses gofpdf for its document production mode. gofpdf is a global community effort and you are invited to make it even better. If you have implemented a new feature or corrected a problem, please consider contributing your change to the project. A contribution that does not directly pertain to the core functionality of gofpdf should be placed in its own directory directly beneath the contrib directory. Here are guidelines for making submissions. Your change should - be compatible with the MIT License - be properly documented - be formatted with go fmt - include an example in fpdf_test.go if appropriate - conform to the standards of golint and go vet, that is, golint . and go vet . should not generate any warnings - not diminish test coverage Pull requests are the preferred means of accepting your changes. gofpdf is released under the MIT License. It is copyrighted by Kurt Jung and the contributors acknowledged below. This package’s code and documentation are closely derived from the FPDF library created by Olivier Plathey, and a number of font and image resources are copied directly from it. Bruno Michel has provided valuable assistance with the code. Drawing support is adapted from the FPDF geometric figures script by David Hernández Sanz. Transparency support is adapted from the FPDF transparency script by Martin Hall-May. Support for gradients and clipping is adapted from FPDF scripts by Andreas Würmser. Support for outline bookmarks is adapted from Olivier Plathey by Manuel Cornes. Layer support is adapted from Olivier Plathey. Support for transformations is adapted from the FPDF transformation script by Moritz Wagner and Andreas Würmser. PDF protection is adapted from the work of Klemen Vodopivec for the FPDF product. Lawrence Kesteloot provided code to allow an image’s extent to be determined prior to placement. Support for vertical alignment within a cell was provided by Stefan Schroeder. Ivan Daniluk generalized the font and image loading code to use the Reader interface while maintaining backward compatibility. Anthony Starks provided code for the Polygon function. Robert Lillack provided the Beziergon function and corrected some naming issues with the internal curve function. Claudio Felber provided implementations for dashed line drawing and generalized font loading. Stani Michiels provided support for multi-segment path drawing with smooth line joins, line join styles, enhanced fill modes, and has helped greatly with package presentation and tests. Templating is adapted by Marcus Downing from the FPDF_Tpl library created by Jan Slabon and Setasign. Jelmer Snoeck contributed packages that generate a variety of barcodes and help with registering images on the web. Jelmer Snoek and Guillermo Pascual augmented the basic HTML functionality with aligned text. Kent Quirk implemented backwards-compatible support for reading DPI from images that support it, and for setting DPI manually and then having it properly taken into account when calculating image size. Paulo Coutinho provided support for static embedded fonts. Dan Meyers added support for embedded JavaScript. David Fish added a generic alias-replacement function to enable, among other things, table of contents functionality. Andy Bakun identified and corrected a problem in which the internal catalogs were not sorted stably. Paul Montag added encoding and decoding functionality for templates, including images that are embedded in templates; this allows templates to be stored independently of gofpdf. Paul also added support for page boxes used in printing PDF documents. Wojciech Matusiak added supported for word spacing. Artem Korotkiy added support of UTF-8 fonts. Dave Barnes added support for imported objects and templates. Brigham Thompson added support for rounded rectangles. Joe Westcott added underline functionality and optimized image storage. Benoit KUGLER contributed support for rectangles with corners of unequal radius, modification times, and for file attachments and annotations. - Remove all legacy code page font support; use UTF-8 exclusively - Improve test coverage as reported by the coverage tool. Example demonstrates the generation of a simple PDF document. Note that since only core fonts are used (in this case Arial, a synonym for Helvetica), an empty string can be specified for the font directory in the call to New(). Note also that the example.Filename() and example.Summary() functions belong to a separate, internal package and are not part of the gofpdf library. If an error occurs at some point during the construction of the document, subsequent method calls exit immediately and the error is finally retrieved with the output call where it can be handled by the application.

Package lumberjack provides a rolling logger. Note that this is v2.0 of lumberjack, and should be imported using gopkg.in thusly: The package name remains simply lumberjack, and the code resides at https://github.com/natefinch/lumberjack under the v2.0 branch. Lumberjack is intended to be one part of a logging infrastructure. It is not an all-in-one solution, but instead is a pluggable component at the bottom of the logging stack that simply controls the files to which logs are written. Lumberjack plays well with any logging package that can write to an io.Writer, including the standard library's log package. Lumberjack assumes that only one process is writing to the output files. Using the same lumberjack configuration from multiple processes on the same machine will result in improper behavior. To use lumberjack with the standard library's log package, just pass it into the SetOutput function when your application starts.

Package godotenv is a go port of the ruby dotenv library (https://github.com/bkeepers/dotenv) Examples/readme can be found on the GitHub page at https://github.com/joho/godotenv The TL;DR is that you make a .env file that looks something like and then in your go code you can call and all the env vars declared in .env will be available through os.Getenv("SOME_ENV_VAR")

Package ebpf is a toolkit for working with eBPF programs. eBPF programs are small snippets of code which are executed directly in a VM in the Linux kernel, which makes them very fast and flexible. Many Linux subsystems now accept eBPF programs. This makes it possible to implement highly application specific logic inside the kernel, without having to modify the actual kernel itself. This package is designed for long-running processes which want to use eBPF to implement part of their application logic. It has no run-time dependencies outside of the library and the Linux kernel itself. eBPF code should be compiled ahead of time using clang, and shipped with your application as any other resource. Use the link subpackage to attach a loaded program to a hook in the kernel. Note that losing all references to Map and Program resources will cause their underlying file descriptors to be closed, potentially removing those objects from the kernel. Always retain a reference by e.g. deferring a Close() of a Collection or LoadAndAssign object until application exit. Special care needs to be taken when handling maps of type ProgramArray, as the kernel erases its contents when the last userspace or bpffs reference disappears, regardless of the map being in active use. ExampleMarshaler shows how to use custom encoding with map methods. ExampleExtractDistance shows how to attach an eBPF socket filter to extract the network distance of an IP host. ExampleSocketELF demonstrates how to load an eBPF program from an ELF, and attach it to a raw socket.

Copyright 2022, Daniela Filipe Bento Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License. Package gitlab implements a GitLab API client. Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.

Package age implements file encryption according to the age-encryption.org/v1 specification. For most use cases, use the Encrypt and Decrypt functions with X25519Recipient and X25519Identity. If passphrase encryption is required, use ScryptRecipient and ScryptIdentity. For compatibility with existing SSH keys use the filippo.io/age/agessh package. age encrypted files are binary and not malleable. For encoding them as text, use the filippo.io/age/armor package. age does not have a global keyring. Instead, since age keys are small, textual, and cheap, you are encouraged to generate dedicated keys for each task and application. Recipient public keys can be passed around as command line flags and in config files, while secret keys should be stored in dedicated files, through secret management systems, or as environment variables. There is no default path for age keys. Instead, they should be stored at application-specific paths. The CLI supports files where private keys are listed one per line, ignoring empty lines and lines starting with "#". These files can be parsed with ParseIdentities. When integrating age into a new system, it's recommended that you only support X25519 keys, and not SSH keys. The latter are supported for manual encryption operations. If you need to tie into existing key management infrastructure, you might want to consider implementing your own Recipient and Identity. Files encrypted with a stable version (not alpha, beta, or release candidate) of age, or with any v1.0.0 beta or release candidate, will decrypt with any later versions of the v1 API. This might change in v2, in which case v1 will be maintained with security fixes for compatibility with older files. If decrypting an older file poses a security risk, doing so might require an explicit opt-in in the API.

Package elasticsearch provides a Go client for Elasticsearch. Create the client with the NewDefaultClient function: The ELASTICSEARCH_URL environment variable is used instead of the default URL, when set. Use a comma to separate multiple URLs. To configure the client, pass a Config object to the NewClient function: When using the Elastic Service (https://elastic.co/cloud), you can use CloudID instead of Addresses. When either Addresses or CloudID is set, the ELASTICSEARCH_URL environment variable is ignored. See the elasticsearch_integration_test.go file and the _examples folder for more information. Call the Elasticsearch APIs by invoking the corresponding methods on the client: See the github.com/elastic/go-elasticsearch/esapi package for more information about using the API. See the github.com/elastic/go-elasticsearch/estransport package for more information about configuring the transport.

Package ini provides INI file read and write functionality in Go.

Package gocql implements a fast and robust Cassandra driver for the Go programming language. Pass a list of initial node IP addresses to NewCluster to create a new cluster configuration: Port can be specified as part of the address, the above is equivalent to: It is recommended to use the value set in the Cassandra config for broadcast_address or listen_address, an IP address not a domain name. This is because events from Cassandra will use the configured IP address, which is used to index connected hosts. If the domain name specified resolves to more than 1 IP address then the driver may connect multiple times to the same host, and will not mark the node being down or up from events. Then you can customize more options (see ClusterConfig): The driver tries to automatically detect the protocol version to use if not set, but you might want to set the protocol version explicitly, as it's not defined which version will be used in certain situations (for example during upgrade of the cluster when some of the nodes support different set of protocol versions than other nodes). The driver advertises the module name and version in the STARTUP message, so servers are able to detect the version. If you use replace directive in go.mod, the driver will send information about the replacement module instead. When ready, create a session from the configuration. Don't forget to Close the session once you are done with it: CQL protocol uses a SASL-based authentication mechanism and so consists of an exchange of server challenges and client response pairs. The details of the exchanged messages depend on the authenticator used. To use authentication, set ClusterConfig.Authenticator or ClusterConfig.AuthProvider. PasswordAuthenticator is provided to use for username/password authentication: It is possible to secure traffic between the client and server with TLS. To use TLS, set the ClusterConfig.SslOpts field. SslOptions embeds *tls.Config so you can set that directly. There are also helpers to load keys/certificates from files. Warning: Due to historical reasons, the SslOptions is insecure by default, so you need to set EnableHostVerification to true if no Config is set. Most users should set SslOptions.Config to a *tls.Config. SslOptions and Config.InsecureSkipVerify interact as follows: For example: To route queries to local DC first, use DCAwareRoundRobinPolicy. For example, if the datacenter you want to primarily connect is called dc1 (as configured in the database): The driver can route queries to nodes that hold data replicas based on partition key (preferring local DC). Note that TokenAwareHostPolicy can take options such as gocql.ShuffleReplicas and gocql.NonLocalReplicasFallback. We recommend running with a token aware host policy in production for maximum performance. The driver can only use token-aware routing for queries where all partition key columns are query parameters. For example, instead of use The DCAwareRoundRobinPolicy can be replaced with RackAwareRoundRobinPolicy, which takes two parameters, datacenter and rack. Instead of dividing hosts with two tiers (local datacenter and remote datacenters) it divides hosts into three (the local rack, the rest of the local datacenter, and everything else). RackAwareRoundRobinPolicy can be combined with TokenAwareHostPolicy in the same way as DCAwareRoundRobinPolicy. Create queries with Session.Query. Query values must not be reused between different executions and must not be modified after starting execution of the query. To execute a query without reading results, use Query.Exec: Single row can be read by calling Query.Scan: Multiple rows can be read using Iter.Scanner: See Example for complete example. The driver automatically prepares DML queries (SELECT/INSERT/UPDATE/DELETE/BATCH statements) and maintains a cache of prepared statements. CQL protocol does not support preparing other query types. When using CQL protocol >= 4, it is possible to use gocql.UnsetValue as the bound value of a column. This will cause the database to ignore writing the column. The main advantage is the ability to keep the same prepared statement even when you don't want to update some fields, where before you needed to make another prepared statement. Session is safe to use from multiple goroutines, so to execute multiple concurrent queries, just execute them from several worker goroutines. Gocql provides synchronously-looking API (as recommended for Go APIs) and the queries are executed asynchronously at the protocol level. Null values are are unmarshalled as zero value of the type. If you need to distinguish for example between text column being null and empty string, you can unmarshal into *string variable instead of string. See Example_nulls for full example. The driver reuses backing memory of slices when unmarshalling. This is an optimization so that a buffer does not need to be allocated for every processed row. However, you need to be careful when storing the slices to other memory structures. When you want to save the data for later use, pass a new slice every time. A common pattern is to declare the slice variable within the scanner loop: The driver supports paging of results with automatic prefetch, see ClusterConfig.PageSize, Session.SetPrefetch, Query.PageSize, and Query.Prefetch. It is also possible to control the paging manually with Query.PageState (this disables automatic prefetch). Manual paging is useful if you want to store the page state externally, for example in a URL to allow users browse pages in a result. You might want to sign/encrypt the paging state when exposing it externally since it contains data from primary keys. Paging state is specific to the CQL protocol version and the exact query used. It is meant as opaque state that should not be modified. If you send paging state from different query or protocol version, then the behaviour is not defined (you might get unexpected results or an error from the server). For example, do not send paging state returned by node using protocol version 3 to a node using protocol version 4. Also, when using protocol version 4, paging state between Cassandra 2.2 and 3.0 is incompatible (https://issues.apache.org/jira/browse/CASSANDRA-10880). The driver does not check whether the paging state is from the same protocol version/statement. You might want to validate yourself as this could be a problem if you store paging state externally. For example, if you store paging state in a URL, the URLs might become broken when you upgrade your cluster. Call Query.PageState(nil) to fetch just the first page of the query results. Pass the page state returned by Iter.PageState to Query.PageState of a subsequent query to get the next page. If the length of slice returned by Iter.PageState is zero, there are no more pages available (or an error occurred). Using too low values of PageSize will negatively affect performance, a value below 100 is probably too low. While Cassandra returns exactly PageSize items (except for last page) in a page currently, the protocol authors explicitly reserved the right to return smaller or larger amount of items in a page for performance reasons, so don't rely on the page having the exact count of items. See Example_paging for an example of manual paging. There are certain situations when you don't know the list of columns in advance, mainly when the query is supplied by the user. Iter.Columns, Iter.RowData, Iter.MapScan and Iter.SliceMap can be used to handle this case. See Example_dynamicColumns. The CQL protocol supports sending batches of DML statements (INSERT/UPDATE/DELETE) and so does gocql. Use Session.NewBatch to create a new batch and then fill-in details of individual queries. Then execute the batch with Session.ExecuteBatch. Logged batches ensure atomicity, either all or none of the operations in the batch will succeed, but they have overhead to ensure this property. Unlogged batches don't have the overhead of logged batches, but don't guarantee atomicity. Updates of counters are handled specially by Cassandra so batches of counter updates have to use CounterBatch type. A counter batch can only contain statements to update counters. For unlogged batches it is recommended to send only single-partition batches (i.e. all statements in the batch should involve only a single partition). Multi-partition batch needs to be split by the coordinator node and re-sent to correct nodes. With single-partition batches you can send the batch directly to the node for the partition without incurring the additional network hop. It is also possible to pass entire BEGIN BATCH .. APPLY BATCH statement to Query.Exec. There are differences how those are executed. BEGIN BATCH statement passed to Query.Exec is prepared as a whole in a single statement. Session.ExecuteBatch prepares individual statements in the batch. If you have variable-length batches using the same statement, using Session.ExecuteBatch is more efficient. See Example_batch for an example. Query.ScanCAS or Query.MapScanCAS can be used to execute a single-statement lightweight transaction (an INSERT/UPDATE .. IF statement) and reading its result. See example for Query.MapScanCAS. Multiple-statement lightweight transactions can be executed as a logged batch that contains at least one conditional statement. All the conditions must return true for the batch to be applied. You can use Session.ExecuteBatchCAS and Session.MapExecuteBatchCAS when executing the batch to learn about the result of the LWT. See example for Session.MapExecuteBatchCAS. Queries can be marked as idempotent. Marking the query as idempotent tells the driver that the query can be executed multiple times without affecting its result. Non-idempotent queries are not eligible for retrying nor speculative execution. Idempotent queries are retried in case of errors based on the configured RetryPolicy. Queries can be retried even before they fail by setting a SpeculativeExecutionPolicy. The policy can cause the driver to retry on a different node if the query is taking longer than a specified delay even before the driver receives an error or timeout from the server. When a query is speculatively executed, the original execution is still executing. The two parallel executions of the query race to return a result, the first received result will be returned. UDTs can be mapped (un)marshaled from/to map[string]interface{} a Go struct (or a type implementing UDTUnmarshaler, UDTMarshaler, Unmarshaler or Marshaler interfaces). For structs, cql tag can be used to specify the CQL field name to be mapped to a struct field: See Example_userDefinedTypesMap, Example_userDefinedTypesStruct, ExampleUDTMarshaler, ExampleUDTUnmarshaler. It is possible to provide observer implementations that could be used to gather metrics: CQL protocol also supports tracing of queries. When enabled, the database will write information about internal events that happened during execution of the query. You can use Query.Trace to request tracing and receive the session ID that the database used to store the trace information in system_traces.sessions and system_traces.events tables. NewTraceWriter returns an implementation of Tracer that writes the events to a writer. Gathering trace information might be essential for debugging and optimizing queries, but writing traces has overhead, so this feature should not be used on production systems with very high load unless you know what you are doing. Example_batch demonstrates how to execute a batch of statements. Example_dynamicColumns demonstrates how to handle dynamic column list. Example_marshalerUnmarshaler demonstrates how to implement a Marshaler and Unmarshaler. Example_nulls demonstrates how to distinguish between null and zero value when needed. Null values are unmarshalled as zero value of the type. If you need to distinguish for example between text column being null and empty string, you can unmarshal into *string field. Example_paging demonstrates how to manually fetch pages and use page state. See also package documentation about paging. Example_set demonstrates how to use sets. Example_userDefinedTypesMap demonstrates how to work with user-defined types as maps. See also Example_userDefinedTypesStruct and examples for UDTMarshaler and UDTUnmarshaler if you want to map to structs. Example_userDefinedTypesStruct demonstrates how to work with user-defined types as structs. See also examples for UDTMarshaler and UDTUnmarshaler if you need more control/better performance.

Package lumberjack provides a rolling logger. Note that this is v2.0 of lumberjack, and should be imported using gopkg.in thusly: The package name remains simply lumberjack, and the code resides at https://github.com/natefinch/lumberjack under the v2.0 branch. Lumberjack is intended to be one part of a logging infrastructure. It is not an all-in-one solution, but instead is a pluggable component at the bottom of the logging stack that simply controls the files to which logs are written. Lumberjack plays well with any logging package that can write to an io.Writer, including the standard library's log package. Lumberjack assumes that only one process is writing to the output files. Using the same lumberjack configuration from multiple processes on the same machine will result in improper behavior. To use lumberjack with the standard library's log package, just pass it into the SetOutput function when your application starts.

package bbolt implements a low-level key/value store in pure Go. It supports fully serializable transactions, ACID semantics, and lock-free MVCC with multiple readers and a single writer. Bolt can be used for projects that want a simple data store without the need to add large dependencies such as Postgres or MySQL. Bolt is a single-level, zero-copy, B+tree data store. This means that Bolt is optimized for fast read access and does not require recovery in the event of a system crash. Transactions which have not finished committing will simply be rolled back in the event of a crash. The design of Bolt is based on Howard Chu's LMDB database project. Bolt currently works on Windows, Mac OS X, and Linux. There are only a few types in Bolt: DB, Bucket, Tx, and Cursor. The DB is a collection of buckets and is represented by a single file on disk. A bucket is a collection of unique keys that are associated with values. Transactions provide either read-only or read-write access to the database. Read-only transactions can retrieve key/value pairs and can use Cursors to iterate over the dataset sequentially. Read-write transactions can create and delete buckets and can insert and remove keys. Only one read-write transaction is allowed at a time. The database uses a read-only, memory-mapped data file to ensure that applications cannot corrupt the database, however, this means that keys and values returned from Bolt cannot be changed. Writing to a read-only byte slice will cause Go to panic. Keys and values retrieved from the database are only valid for the life of the transaction. When used outside the transaction, these byte slices can point to different data or can point to invalid memory which will cause a panic.

Package sprig provides template functions for Go. This package contains a number of utility functions for working with data inside of Go `html/template` and `text/template` files. To add these functions, use the `template.Funcs()` method: Note that you should add the function map before you parse any template files. See http://masterminds.github.io/sprig/ for more detailed documentation on each of the available functions.

package bbolt implements a low-level key/value store in pure Go. It supports fully serializable transactions, ACID semantics, and lock-free MVCC with multiple readers and a single writer. Bolt can be used for projects that want a simple data store without the need to add large dependencies such as Postgres or MySQL. Bolt is a single-level, zero-copy, B+tree data store. This means that Bolt is optimized for fast read access and does not require recovery in the event of a system crash. Transactions which have not finished committing will simply be rolled back in the event of a crash. The design of Bolt is based on Howard Chu's LMDB database project. Bolt currently works on Windows, Mac OS X, and Linux. There are only a few types in Bolt: DB, Bucket, Tx, and Cursor. The DB is a collection of buckets and is represented by a single file on disk. A bucket is a collection of unique keys that are associated with values. Transactions provide either read-only or read-write access to the database. Read-only transactions can retrieve key/value pairs and can use Cursors to iterate over the dataset sequentially. Read-write transactions can create and delete buckets and can insert and remove keys. Only one read-write transaction is allowed at a time. The database uses a read-only, memory-mapped data file to ensure that applications cannot corrupt the database, however, this means that keys and values returned from Bolt cannot be changed. Writing to a read-only byte slice will cause Go to panic. Keys and values retrieved from the database are only valid for the life of the transaction. When used outside the transaction, these byte slices can point to different data or can point to invalid memory which will cause a panic.

Sprig: Template functions for Go. This package contains a number of utility functions for working with data inside of Go `html/template` and `text/template` files. To add these functions, use the `template.Funcs()` method: Note that you should add the function map before you parse any template files. See http://masterminds.github.io/sprig/ for more detailed documentation on each of the available functions.

Package config provides utilities for loading configuration from multiple sources that can be used to configure the SDK's API clients, and utilities. The config package will load configuration from environment variables, AWS shared configuration file (~/.aws/config), and AWS shared credentials file (~/.aws/credentials). Use the LoadDefaultConfig to load configuration from all the SDK's supported sources, and resolve credentials using the SDK's default credential chain. LoadDefaultConfig allows for a variadic list of additional Config sources that can provide one or more configuration values which can be used to programmatically control the resolution of a specific value, or allow for broader range of additional configuration sources not supported by the SDK. A Config source implements one or more provider interfaces defined in this package. Config sources passed in will take precedence over the default environment and shared config sources used by the SDK. If one or more Config sources implement the same provider interface, priority will be handled by the order in which the sources were passed in. A number of helpers (prefixed by “With“) are provided in this package that implement their respective provider interface. These helpers should be used for overriding configuration programmatically at runtime.

Package cloud is the root of the packages used to access Google Cloud Services. See https://godoc.org/cloud.google.com/go for a full list of sub-packages. All clients in sub-packages are configurable via client options. These options are described here: https://godoc.org/google.golang.org/api/option. All the clients in sub-packages support authentication via Google Application Default Credentials (see https://cloud.google.com/docs/authentication/production), or by providing a JSON key file for a Service Account. See the authentication examples in this package for details. By default, all requests in sub-packages will run indefinitely, retrying on transient errors when correctness allows. To set timeouts or arrange for cancellation, use contexts. See the examples for details. Do not attempt to control the initial connection (dialing) of a service by setting a timeout on the context passed to NewClient. Dialing is non-blocking, so timeouts would be ineffective and would only interfere with credential refreshing, which uses the same context. Connection pooling differs in clients based on their transport. Cloud clients either rely on HTTP or gRPC transports to communicate with Google Cloud. Cloud clients that use HTTP (bigquery, compute, storage, and translate) rely on the underlying HTTP transport to cache connections for later re-use. These are cached to the default http.MaxIdleConns and http.MaxIdleConnsPerHost settings in http.DefaultTransport. For gRPC clients (all others in this repo), connection pooling is configurable. Users of cloud client libraries may specify option.WithGRPCConnectionPool(n) as a client option to NewClient calls. This configures the underlying gRPC connections to be pooled and addressed in a round robin fashion. Minimal docker images like Alpine lack CA certificates. This causes RPCs to appear to hang, because gRPC retries indefinitely. See https://github.com/GoogleCloudPlatform/google-cloud-go/issues/928 for more information. To see gRPC logs, set the environment variable GRPC_GO_LOG_SEVERITY_LEVEL. See https://godoc.org/google.golang.org/grpc/grpclog for more information. For HTTP logging, set the GODEBUG environment variable to "http2debug=1" or "http2debug=2". Google Application Default Credentials is the recommended way to authorize and authenticate clients. For information on how to create and obtain Application Default Credentials, see https://developers.google.com/identity/protocols/application-default-credentials. To arrange for an RPC to be canceled, use context.WithCancel. You can use a file with credentials to authenticate and authorize, such as a JSON key file associated with a Google service account. Service Account keys can be created and downloaded from https://console.developers.google.com/permissions/serviceaccounts. This example uses the Datastore client, but the same steps apply to the other client libraries underneath this package. In some cases (for instance, you don't want to store secrets on disk), you can create credentials from in-memory JSON and use the WithCredentials option. The google package in this example is at golang.org/x/oauth2/google. This example uses the PubSub client, but the same steps apply to the other client libraries underneath this package. To set a timeout for an RPC, use context.WithTimeout.

Package ini provides INI file read and write functionality in Go.

Package excelize providing a set of functions that allow you to write to and read from XLSX / XLSM / XLTM files. Supports reading and writing spreadsheet documents generated by Microsoft Excel™ 2007 and later. Supports complex components by high compatibility, and provided streaming API for generating or reading data from a worksheet with huge amounts of data. This library needs Go version 1.15 or later. See https://xuri.me/excelize for more information about this package.

Package ini implements parsing of the AWS shared config file.

Package archiver facilitates convenient, cross-platform, high-level archival and compression operations for a variety of formats and compression algorithms. This package and its dependencies are written in pure Go (not cgo) and have no external dependencies, so they should run on all major platforms. (It also comes with a command for CLI use in the cmd/arc folder.) Each supported format or algorithm has a unique type definition that implements the interfaces corresponding to the tasks they perform. For example, the Tar type implements Reader, Writer, Archiver, Unarchiver, Walker, and several other interfaces. The most common functions are implemented at the package level for convenience: Archive, Unarchive, Walk, Extract, CompressFile, and DecompressFile. With these, the format type is chosen implicitly, and a sane default configuration is used. To customize a format's configuration, create an instance of its struct with its fields set to the desired values. You can also use and customize the handy Default* (replace the wildcard with the format's type name) for a quick, one-off instance of the format's type. To obtain a new instance of a format's struct with the default config, use the provided New*() functions. This is not required, however. An empty struct of any type, for example &Zip{} is perfectly valid, so you may create the structs manually, too. The examples on this page show how either may be done. See the examples in this package for an idea of how to wield this package for common tasks. Most of the examples which are specific to a certain format type, for example Zip, can be applied to other types that implement the same interfaces. For example, using Zip is very similar to using Tar or TarGz (etc), and using Gz is very similar to using Sz or Xz (etc). When creating archives or compressing files using a specific instance of the format's type, the name of the output file MUST match that of the format, to prevent confusion later on. If you absolutely need a different file extension, you may rename the file afterward. Values in this package are NOT safe for concurrent use. There is no performance benefit of reusing them, and since they may contain important state (especially while walking, reading, or writing), it is NOT recommended to reuse values from this package or change their configuration after they are in use.

Package elasticsearch provides a Go client for Elasticsearch. Create the client with the NewDefaultClient function: The ELASTICSEARCH_URL environment variable is used instead of the default URL, when set. Use a comma to separate multiple URLs. To configure the client, pass a Config object to the NewClient function: When using the Elastic Service (https://elastic.co/cloud), you can use CloudID instead of Addresses. When either Addresses or CloudID is set, the ELASTICSEARCH_URL environment variable is ignored. See the elasticsearch_integration_test.go file and the _examples folder for more information. Call the Elasticsearch APIs by invoking the corresponding methods on the client: See the github.com/elastic/go-elasticsearch/esapi package for more information about using the API. See the github.com/elastic/go-elasticsearch/estransport package for more information about configuring the transport.

Package flags provides an extensive command line option parser. The flags package is similar in functionality to the go built-in flag package but provides more options and uses reflection to provide a convenient and succinct way of specifying command line options. The following features are supported in go-flags: Additional features specific to Windows: The flags package uses structs, reflection and struct field tags to allow users to specify command line options. This results in very simple and concise specification of your application options. For example: This specifies one option with a short name -v and a long name --verbose. When either -v or --verbose is found on the command line, a 'true' value will be appended to the Verbose field. e.g. when specifying -vvv, the resulting value of Verbose will be {[true, true, true]}. Slice options work exactly the same as primitive type options, except that whenever the option is encountered, a value is appended to the slice. Map options from string to primitive type are also supported. On the command line, you specify the value for such an option as key:value. For example Then, the AuthorInfo map can be filled with something like -a name:Jesse -a "surname:van den Kieboom". Finally, for full control over the conversion between command line argument values and options, user defined types can choose to implement the Marshaler and Unmarshaler interfaces. The following is a list of tags for struct fields supported by go-flags: Either the `short:` tag or the `long:` must be specified to make the field eligible as an option. Option groups are a simple way to semantically separate your options. All options in a particular group are shown together in the help under the name of the group. Namespaces can be used to specify option long names more precisely and emphasize the options affiliation to their group. There are currently three ways to specify option groups. The flags package also has basic support for commands. Commands are often used in monolithic applications that support various commands or actions. Take git for example, all of the add, commit, checkout, etc. are called commands. Using commands you can easily separate multiple functions of your application. There are currently two ways to specify a command. The most common, idiomatic way to implement commands is to define a global parser instance and implement each command in a separate file. These command files should define a go init function which calls AddCommand on the global parser. When parsing ends and there is an active command and that command implements the Commander interface, then its Execute method will be run with the remaining command line arguments. Command structs can have options which become valid to parse after the command has been specified on the command line, in addition to the options of all the parent commands. I.e. considering a -v flag on the parser and an add command, the following are equivalent: However, if the -v flag is defined on the add command, then the first of the two examples above would fail since the -v flag is not defined before the add command. go-flags has builtin support to provide bash completion of flags, commands and argument values. To use completion, the binary which uses go-flags can be invoked in a special environment to list completion of the current command line argument. It should be noted that this `executes` your application, and it is up to the user to make sure there are no negative side effects (for example from init functions). Setting the environment variable `GO_FLAGS_COMPLETION=1` enables completion by replacing the argument parsing routine with the completion routine which outputs completions for the passed arguments. The basic invocation to complete a set of arguments is therefore: where `completion-example` is the binary, `arg1` and `arg2` are the current arguments, and `arg3` (the last argument) is the argument to be completed. If the GO_FLAGS_COMPLETION is set to "verbose", then descriptions of possible completion items will also be shown, if there are more than 1 completion items. To use this with bash completion, a simple file can be written which calls the binary which supports go-flags completion: Completion requires the parser option PassDoubleDash and is therefore enforced if the environment variable GO_FLAGS_COMPLETION is set. Customized completion for argument values is supported by implementing the flags.Completer interface for the argument value type. An example of a type which does so is the flags.Filename type, an alias of string allowing simple filename completion. A slice or array argument value whose element type implements flags.Completer will also be completed.

Package archiver facilitates convenient, cross-platform, high-level archival and compression operations for a variety of formats and compression algorithms. This package and its dependencies are written in pure Go (not cgo) and have no external dependencies, so they should run on all major platforms. (It also comes with a command for CLI use in the cmd/arc folder.) Each supported format or algorithm has a unique type definition that implements the interfaces corresponding to the tasks they perform. For example, the Tar type implements Reader, Writer, Archiver, Unarchiver, Walker, and several other interfaces. The most common functions are implemented at the package level for convenience: Archive, Unarchive, Walk, Extract, CompressFile, and DecompressFile. With these, the format type is chosen implicitly, and a sane default configuration is used. To customize a format's configuration, create an instance of its struct with its fields set to the desired values. You can also use and customize the handy Default* (replace the wildcard with the format's type name) for a quick, one-off instance of the format's type. To obtain a new instance of a format's struct with the default config, use the provided New*() functions. This is not required, however. An empty struct of any type, for example &Zip{} is perfectly valid, so you may create the structs manually, too. The examples on this page show how either may be done. See the examples in this package for an idea of how to wield this package for common tasks. Most of the examples which are specific to a certain format type, for example Zip, can be applied to other types that implement the same interfaces. For example, using Zip is very similar to using Tar or TarGz (etc), and using Gz is very similar to using Sz or Xz (etc). When creating archives or compressing files using a specific instance of the format's type, the name of the output file MUST match that of the format, to prevent confusion later on. If you absolutely need a different file extension, you may rename the file afterward. Values in this package are NOT safe for concurrent use. There is no performance benefit of reusing them, and since they may contain important state (especially while walking, reading, or writing), it is NOT recommended to reuse values from this package or change their configuration after they are in use.

Copyright 2018 Twitch Interactive, Inc. All Rights Reserved. Licensed under the Apache License, Version 2.0 (the "License"). You may not use this file except in compliance with the License. A copy of the License is located at or in the "license" file accompanying this file. This file is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License. Package twirp provides core types used in generated Twirp servers and client. Twirp services handle errors using the `twirp.Error` interface. For example, a server method may return an InvalidArgumentError: And the same twirp.Error is returned by the client, for example: Clients may also return Internal errors if something failed on the system: the server, the network, or the client itself (i.e. failure parsing response). Copyright 2018 Twitch Interactive, Inc. All Rights Reserved. Licensed under the Apache License, Version 2.0 (the "License"). You may not use this file except in compliance with the License. A copy of the License is located at or in the "license" file accompanying this file. This file is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License. Copyright 2018 Twitch Interactive, Inc. All Rights Reserved. Licensed under the Apache License, Version 2.0 (the "License"). You may not use this file except in compliance with the License. A copy of the License is located at or in the "license" file accompanying this file. This file is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.

Package locafero looks for files and directories in an {fs.Fs} filesystem.

Package elasticsearch provides a Go client for Elasticsearch. Create the client with the NewDefaultClient function: The ELASTICSEARCH_URL environment variable is used instead of the default URL, when set. Use a comma to separate multiple URLs. To configure the client, pass a Config object to the NewClient function: When using the Elastic Service (https://elastic.co/cloud), you can use CloudID instead of Addresses. When either Addresses or CloudID is set, the ELASTICSEARCH_URL environment variable is ignored. See the elasticsearch_integration_test.go file and the _examples folder for more information. Call the Elasticsearch APIs by invoking the corresponding methods on the client: See the github.com/elastic/go-elasticsearch/esapi package for more information about using the API. See the github.com/elastic/elastic-transport-go package for more information about configuring the transport.

SQL Schema migration tool for Go. Key features: To install the library and command line program, use the following: The main command is called sql-migrate. Each command requires a configuration file (which defaults to dbconfig.yml, but can be specified with the -config flag). This config file should specify one or more environments: The `table` setting is optional and will default to `gorp_migrations`. The environment that will be used can be specified with the -env flag (defaults to development). Use the --help flag in combination with any of the commands to get an overview of its usage: The up command applies all available migrations. By contrast, down will only apply one migration by default. This behavior can be changed for both by using the -limit parameter. The redo command will unapply the last migration and reapply it. This is useful during development, when you're writing migrations. Use the status command to see the state of the applied migrations: If you are using MySQL, you must append ?parseTime=true to the datasource configuration. For example: See https://github.com/go-sql-driver/mysql#parsetime for more information. Import sql-migrate into your application: Set up a source of migrations, this can be from memory, from a set of files or from bindata (more on that later): Then use the Exec function to upgrade your database: Note that n can be greater than 0 even if there is an error: any migration that succeeded will remain applied even if a later one fails. The full set of capabilities can be found in the API docs below. Migrations are defined in SQL files, which contain a set of SQL statements. Special comments are used to distinguish up and down migrations. You can put multiple statements in each block, as long as you end them with a semicolon (;). If you have complex statements which contain semicolons, use StatementBegin and StatementEnd to indicate boundaries: The order in which migrations are applied is defined through the filename: sql-migrate will sort migrations based on their name. It's recommended to use an increasing version number or a timestamp as the first part of the filename. Normally each migration is run within a transaction in order to guarantee that it is fully atomic. However some SQL commands (for example creating an index concurrently in PostgreSQL) cannot be executed inside a transaction. In order to execute such a command in a migration, the migration can be run using the notransaction option: If you like your Go applications self-contained (that is: a single binary): use packr (https://github.com/gobuffalo/packr) to embed the migration files. Just write your migration files as usual, as a set of SQL files in a folder. Use the PackrMigrationSource in your application to find the migrations: If you already have a box and would like to use a subdirectory: As an alternative, but slightly less maintained, you can use bindata (https://github.com/shuLhan/go-bindata) to embed the migration files. Just write your migration files as usual, as a set of SQL files in a folder. Then use bindata to generate a .go file with the migrations embedded: The resulting bindata.go file will contain your migrations. Remember to regenerate your bindata.go file whenever you add/modify a migration (go generate will help here, once it arrives). Use the AssetMigrationSource in your application to find the migrations: Both Asset and AssetDir are functions provided by bindata. Then proceed as usual. Adding a new migration source means implementing MigrationSource. The resulting slice of migrations will be executed in the given order, so it should usually be sorted by the Id field.

Package kms provides the API client, operations, and parameter types for AWS Key Management Service. Key Management Service (KMS) is an encryption and key management web service. This guide describes the KMS operations that you can call programmatically. For general information about KMS, see the Key Management Service Developer Guide. KMS has replaced the term customer master key (CMK) with KMS key and KMS key. The concept has not changed. To prevent breaking changes, KMS is keeping some variations of this term. Amazon Web Services provides SDKs that consist of libraries and sample code for various programming languages and platforms (Java, Ruby, .Net, macOS, Android, etc.). The SDKs provide a convenient way to create programmatic access to KMS and other Amazon Web Services services. For example, the SDKs take care of tasks such as signing requests (see below), managing errors, and retrying requests automatically. For more information about the Amazon Web Services SDKs, including how to download and install them, see Tools for Amazon Web Services. We recommend that you use the Amazon Web Services SDKs to make programmatic API calls to KMS. If you need to use FIPS 140-2 validated cryptographic modules when communicating with Amazon Web Services, use the FIPS endpoint in your preferred Amazon Web Services Region. For more information about the available FIPS endpoints, see Service endpointsin the Key Management Service topic of the Amazon Web Services General Reference. All KMS API calls must be signed and be transmitted using Transport Layer Security (TLS). KMS recommends you always use the latest supported TLS version. Clients must also support cipher suites with Perfect Forward Secrecy (PFS) such as Ephemeral Diffie-Hellman (DHE) or Elliptic Curve Ephemeral Diffie-Hellman (ECDHE). Most modern systems such as Java 7 and later support these modes. Requests must be signed using an access key ID and a secret access key. We strongly recommend that you do not use your Amazon Web Services account root access key ID and secret access key for everyday work. You can use the access key ID and secret access key for an IAM user or you can use the Security Token Service (STS) to generate temporary security credentials and use those to sign requests. All KMS requests must be signed with Signature Version 4. KMS supports CloudTrail, a service that logs Amazon Web Services API calls and related events for your Amazon Web Services account and delivers them to an Amazon S3 bucket that you specify. By using the information collected by CloudTrail, you can determine what requests were made to KMS, who made the request, when it was made, and so on. To learn more about CloudTrail, including how to turn it on and find your log files, see the CloudTrail User Guide. For more information about credentials and request signing, see the following: Amazon Web Services Security Credentials Temporary Security Credentials Signature Version 4 Signing Process Of the API operations discussed in this guide, the following will prove the most useful for most applications. You will likely perform operations other than these, such as creating keys and assigning policies, by using the console.

Package generated provides a function that parses a source file and reports whether it contains a "// Code generated … DO NOT EDIT." line comment. It implements the specification at https://go.dev/s/generatedcode. The first priority is correctness (no false negatives, no false positives). It must return accurate results even if the input source code is formatted unconventionally. The second priority is performance. The current version uses bufio.Reader and ReadBytes. Performance can be optimized further by using lower level I/O primitives and allocating less. That can be explored later.

Package contains a program that generates code to register a directory and its contents as zip data for statik file system.

Package filestore implements a Blockstore which is able to read certain blocks of data directly from its original location in the filesystem. In a Filestore, object leaves are stored as FilestoreNodes. FilestoreNodes include a filesystem path and an offset, allowing a Blockstore dealing with such blocks to avoid storing the whole contents and reading them from their filesystem location instead.

Package endpointdiscovery provides a feature implemented in the AWS SDK for Go V2 that allows client to fetch a valid endpoint to serve an API request. Discovered endpoints are stored in an internal thread-safe cache to reduce the number of calls made to fetch the endpoint. Endpoint discovery stores endpoint by associating to a generated cache key. Cache key is built using service-modeled sdkId and any service-defined input identifiers provided by the customer. Endpoint cache keys follow the grammar: The endpoint discovery cache implementation is internal. Clients resolves the cache size to 10 entries. Each entry may contain multiple host addresses as returned by the service. Each discovered endpoint has a TTL associated to it, and are evicted from cache lazily i.e. when client tries to retrieve an endpoint but finds an expired entry instead. Endpoint discovery feature can be turned on by setting the `AWS_ENABLE_ENDPOINT_DISCOVERY` env variable to TRUE. By default, the feature is set to AUTO - indicating operations that require endpoint discovery always use it. To completely turn off the feature, one should set the value as FALSE. Similar configuration rules apply for shared config file where key is `endpoint_discovery_enabled`.

Package sftp implements the SSH File Transfer Protocol as described in https://filezilla-project.org/specs/draft-ietf-secsh-filexfer-02.txt

Package secretsmanager provides the API client, operations, and parameter types for AWS Secrets Manager. Amazon Web Services Secrets Manager provides a service to enable you to store, manage, and retrieve, secrets. This guide provides descriptions of the Secrets Manager API. For more information about using this service, see the Amazon Web Services Secrets Manager User Guide. This version of the Secrets Manager API Reference documents the Secrets Manager API version 2017-10-17. For a list of endpoints, see Amazon Web Services Secrets Manager endpoints. We welcome your feedback. Send your comments to awssecretsmanager-feedback@amazon.com, or post your feedback and questions in the Amazon Web Services Secrets Manager Discussion Forum. For more information about the Amazon Web Services Discussion Forums, see Forums Help. Amazon Web Services Secrets Manager supports Amazon Web Services CloudTrail, a service that records Amazon Web Services API calls for your Amazon Web Services account and delivers log files to an Amazon S3 bucket. By using information that's collected by Amazon Web Services CloudTrail, you can determine the requests successfully made to Secrets Manager, who made the request, when it was made, and so on. For more about Amazon Web Services Secrets Manager and support for Amazon Web Services CloudTrail, see Logging Amazon Web Services Secrets Manager Events with Amazon Web Services CloudTrailin the Amazon Web Services Secrets Manager User Guide. To learn more about CloudTrail, including enabling it and find your log files, see the Amazon Web Services CloudTrail User Guide.

Package cloudflare implements the Cloudflare v4 API. File contains helper methods for accepting variants (pointers, values, slices, etc) of a particular type and returning them in another. A common use is pointer to values and back. _Most_ follow the convention of (where <type> is a Golang type such as Bool): <type>Ptr: Accepts a value and returns a pointer. <type>: Accepts a pointer and returns a value. <type>PtrSlice: Accepts a slice of values and returns a slice of pointers. <type>Slice: Accepts a slice of pointers and returns a slice of values. <type>PtrMap: Accepts a string map of values into a string map of pointers. <type>Map: Accepts a string map of pointers into a string map of values. Not all Golang types are covered here, only those that are commonly used.

Package cloudwatchlogs provides the API client, operations, and parameter types for Amazon CloudWatch Logs. You can use Amazon CloudWatch Logs to monitor, store, and access your log files from EC2 instances, CloudTrail, and other sources. You can then retrieve the associated log data from CloudWatch Logs using the CloudWatch console. Alternatively, you can use CloudWatch Logs commands in the Amazon Web Services CLI, CloudWatch Logs API, or CloudWatch Logs SDK. You can use CloudWatch Logs to: Monitor logs from EC2 instances in real time: You can use CloudWatch Logs to monitor applications and systems using log data. For example, CloudWatch Logs can track the number of errors that occur in your application logs. Then, it can send you a notification whenever the rate of errors exceeds a threshold that you specify. CloudWatch Logs uses your log data for monitoring so no code changes are required. For example, you can monitor application logs for specific literal terms (such as "NullReferenceException"). You can also count the number of occurrences of a literal term at a particular position in log data (such as "404" status codes in an Apache access log). When the term you are searching for is found, CloudWatch Logs reports the data to a CloudWatch metric that you specify. Monitor CloudTrail logged events: You can create alarms in CloudWatch and receive notifications of particular API activity as captured by CloudTrail. You can use the notification to perform troubleshooting. Archive log data: You can use CloudWatch Logs to store your log data in highly durable storage. You can change the log retention setting so that any log events earlier than this setting are automatically deleted. The CloudWatch Logs agent helps to quickly send both rotated and non-rotated log data off of a host and into the log service. You can then access the raw log data when you need it.

Package zap provides fast, structured, leveled logging. For applications that log in the hot path, reflection-based serialization and string formatting are prohibitively expensive - they're CPU-intensive and make many small allocations. Put differently, using json.Marshal and fmt.Fprintf to log tons of interface{} makes your application slow. Zap takes a different approach. It includes a reflection-free, zero-allocation JSON encoder, and the base Logger strives to avoid serialization overhead and allocations wherever possible. By building the high-level SugaredLogger on that foundation, zap lets users choose when they need to count every allocation and when they'd prefer a more familiar, loosely typed API. In contexts where performance is nice, but not critical, use the SugaredLogger. It's 4-10x faster than other structured logging packages and supports both structured and printf-style logging. Like log15 and go-kit, the SugaredLogger's structured logging APIs are loosely typed and accept a variadic number of key-value pairs. (For more advanced use cases, they also accept strongly typed fields - see the SugaredLogger.With documentation for details.) By default, loggers are unbuffered. However, since zap's low-level APIs allow buffering, calling Sync before letting your process exit is a good habit. In the rare contexts where every microsecond and every allocation matter, use the Logger. It's even faster than the SugaredLogger and allocates far less, but it only supports strongly-typed, structured logging. Choosing between the Logger and SugaredLogger doesn't need to be an application-wide decision: converting between the two is simple and inexpensive. The simplest way to build a Logger is to use zap's opinionated presets: NewExample, NewProduction, and NewDevelopment. These presets build a logger with a single function call: Presets are fine for small projects, but larger projects and organizations naturally require a bit more customization. For most users, zap's Config struct strikes the right balance between flexibility and convenience. See the package-level BasicConfiguration example for sample code. More unusual configurations (splitting output between files, sending logs to a message queue, etc.) are possible, but require direct use of go.uber.org/zap/zapcore. See the package-level AdvancedConfiguration example for sample code. The zap package itself is a relatively thin wrapper around the interfaces in go.uber.org/zap/zapcore. Extending zap to support a new encoding (e.g., BSON), a new log sink (e.g., Kafka), or something more exotic (perhaps an exception aggregation service, like Sentry or Rollbar) typically requires implementing the zapcore.Encoder, zapcore.WriteSyncer, or zapcore.Core interfaces. See the zapcore documentation for details. Similarly, package authors can use the high-performance Encoder and Core implementations in the zapcore package to build their own loggers. An FAQ covering everything from installation errors to design decisions is available at https://github.com/uber-go/zap/blob/master/FAQ.md.

Package logging implements a logging infrastructure for Go. It supports different logging backends like syslog, file and memory. Multiple backends can be utilized with different log levels per backend and logger.

Package fileexporter exports data to files.

Package elasticsearch provides a Go client for Elasticsearch. Create the client with the NewDefaultClient function: The ELASTICSEARCH_URL environment variable is used instead of the default URL, when set. Use a comma to separate multiple URLs. To configure the client, pass a Config object to the NewClient function: See the elasticsearch_integration_test.go file and the _examples folder for more information. Call the Elasticsearch APIs by invoking the corresponding methods on the client: See the github.com/elastic/go-elasticsearch/esapi package for more information and examples.