Eval

Package radix implements all functionality needed to work with redis and all things related to it, including redis cluster, pubsub, sentinel, scanning, lua scripting, and more. For a single node redis instance use NewPool to create a connection pool. The connection pool is thread-safe and will automatically create, reuse, and recreate connections as needed: If you're using sentinel or cluster you should use NewSentinel or NewCluster (respectively) to create your client instead. Any redis command can be performed by passing a Cmd into a Client's Do method. Each Cmd should only be used once. The return from the Cmd can be captured into any appopriate go primitive type, or a slice, map, or struct, if the command returns an array. FlatCmd can also be used if you wish to use non-string arguments like integers, slices, maps, or structs, and have them automatically be flattened into a single string slice. Cmd and FlatCmd can unmarshal results into a struct. The results must be a key/value array, such as that returned by HGETALL. Exported field names will be used as keys, unless the fields have the "redis" tag: Embedded structs will inline that struct's fields into the parent's: The same rules for field naming apply when a struct is passed into FlatCmd as an argument. Cmd and FlatCmd both implement the Action interface. Other Actions include Pipeline, WithConn, and EvalScript.Cmd. Any of these may be passed into any Client's Do method. There are two ways to perform transactions in redis. The first is with the MULTI/EXEC commands, which can be done using the WithConn Action (see its example). The second is using EVAL with lua scripting, which can be done using the EvalScript Action (again, see its example). EVAL with lua scripting is recommended in almost all cases. It only requires a single round-trip, it's infinitely more flexible than MULTI/EXEC, it's simpler to code, and for complex transactions, which would otherwise need a WATCH statement with MULTI/EXEC, it's significantly faster. All the client creation functions (e.g. NewPool) take in either a ConnFunc or a ClientFunc via their options. These can be used in order to set up timeouts on connections, perform authentication commands, or even implement custom pools. All interfaces in this package were designed such that they could have custom implementations. There is no dependency within radix that demands any interface be implemented by a particular underlying type, so feel free to create your own Pools or Conns or Actions or whatever makes your life easier. Errors returned from redis can be explicitly checked for using the the resp2.Error type. Note that the errors.As function, introduced in go 1.13, should be used. Use the golang.org/x/xerrors package if you're using an older version of go. Implicit pipelining is an optimization implemented and enabled in the default Pool implementation (and therefore also used by Cluster and Sentinel) which involves delaying concurrent Cmds and FlatCmds a small amount of time and sending them to redis in a single batch, similar to manually using a Pipeline. By doing this radix significantly reduces the I/O and CPU overhead for concurrent requests. Note that only commands which do not block are eligible for implicit pipelining. See the documentation on Pool for more information about the current implementation of implicit pipelining and for how to configure or disable the feature. For a performance comparisons between Clients with and without implicit pipelining see the benchmark results in the README.md.

Package eval implements evaluation of GoLang expression at runtime. Requirements for expression: What does supported: Supported expression: Predefined types (no need to pass it via args): Implemented built-in functions (no need to pass it via args): Simple example: Complicated example: Example with error in expression: Package eval built on top of reflection, go/ast, go/parser, go/token & go/constant. To create Expression it possible to use MakeExpression or some of Parse* functions. All of them use pkgPath to control access rights. pkgPath used when: 1. Accessing struct private field. If type of struct belong to pkgPath then all access to struct fields can modify its value (for example, it is possible to set such fields in composite literal). 2. Creating type in composite literal. All created in expression structures belong to pkgPath. When Expression is ready it may be evaluated multiple times. Evaluation done via Eval* methods: In most cases EvalToInterface should be enough and it is easy to use. Evaluation performance: If you found a bug (result of this package evaluation differs from evaluation by Go itself) - please report bug at github.com/apaxa-go/eval.

Package radix implements all functionality needed to work with redis and all things related to it, including redis cluster, pubsub, sentinel, scanning, lua scripting, and more. This package has extensive examples documenting advanced behavior not covered here. For a single redis instance use PoolConfig to create a connection pool. The connection pool implements the Client interface. It is thread-safe and will automatically create, reuse, and recreate connections as needed: If you're using sentinel or cluster you should use SentinelConfig or ClusterConfig (respectively) to create your Client instead. Any redis command can be performed by passing a Cmd into a Client's Do method. Each Cmd instance should only be used once. The return from the Cmd can be captured into any appopriate go primitive type, or a slice, map, or struct, if the command returns an array. FlatCmd can also be used if you wish to use non-string arguments like integers, slices, maps, or structs, and have them automatically be flattened into a single string slice. Cmd and FlatCmd both implement the Action interface. Other Actions include Pipeline, WithConn, and EvalScript.Cmd. Any of these may be passed into any Client's Do method. There are two ways to perform transactions in redis. The first is with the MULTI/EXEC commands, which can be done using the WithConn Action (see its example). The second is using EVAL with lua scripting, which can be done using the EvalScript Action (again, see its example). EVAL with lua scripting is recommended in almost all cases. It only requires a single round-trip, it's infinitely more flexible than MULTI/EXEC, it's simpler to code, and for complex transactions, which would otherwise need a WATCH statement with MULTI/EXEC, it's significantly faster. Dialer has fields like AuthPass and SelectDB which can be used to configure Conns at creation. PoolConfig takes a Dialer as one of its fields, so that all Conns the Pool creates will be created with those settings. Other Clients which create their own Pools, like Cluster and Sentinel, will take in a PoolConfig which can be used to configure the Pools they create. For example, to create a Cluster instance which uses a particular AUTH password on all Conns: All interfaces in this package were designed such that they could have custom implementations. There is no dependency within radix that demands any interface be implemented by a particular underlying type, so feel free to create your own Pools or Conns or Actions or whatever makes your life easier. Errors returned from redis can be explicitly checked for using the the resp3.SimpleError type. Note that the errors.As or errors.Is functions, introduced in go 1.13, should be used.

Package skylark provides a Skylark interpreter. Skylark values are represented by the Value interface. The following built-in Value types are known to the evaluator: Client applications may define new data types that satisfy at least the Value interface. Such types may provide additional operations by implementing any of these optional interfaces: Client applications may also define domain-specific functions in Go and make them available to Skylark programs. Use NewBuiltin to construct a built-in value that wraps a Go function. The implementation of the Go function may use UnpackArgs to make sense of the positional and keyword arguments provided by the caller. Skylark's None value is not equal to Go's nil, but nil may be assigned to a Skylark Value. Be careful to avoid allowing Go nil values to leak into Skylark data structures. The Compare operation requires two arguments of the same type, but this constraint cannot be expressed in Go's type system. (This is the classic "binary method problem".) So, each Value type's CompareSameType method is a partial function that compares a value only against others of the same type. Use the package's standalone Compare (or Equal) function to compare an arbitrary pair of values. To parse and evaluate a Skylark source file, use ExecFile. The Eval function evaluates a single expression. All evaluator functions require a Thread parameter which defines the "thread-local storage" of a Skylark thread and may be used to plumb application state through Sklyark code and into callbacks. When evaluation fails it returns an EvalError from which the application may obtain a backtrace of active Skylark calls.

Packages in the Plugin directory contain plugins for [goa v2](https://godoc.org/goa.design/goa/v3). Plugins can extend the goa DSL, generate new artifacts and modify the output of existing generators. There are currently two plugins in the directory: The [goakit](https://godoc.org/goa.design/plugins/goakit) plugin generates code that integrates with the [go-kit](https://github.com/go-kit/kit) library. The [cors](https://godoc.org/goa.design/plugins/cors) plugin adds new DSL to define CORS policies. The plugin generates HTTP server code that respond to CORS requests in compliance with the policies defined in the design. Writing a plugin consists of two steps: 1. Writing the functions that gets called by the goa tool during code generation. 2. Registering the functions with the goa tool. A plugin may implement the "gen" goa command, the "example" goa command or both. In each case a plugin may register one or two functions: the first function called "Prepare" gets called prior to any code generation actually happening. The function can modify the design data structures before goa uses them to generate code. The second function called "Generate" does the actual code generation. The signature of the Generate function is: where: The function must return the entire set of generated files (even the files that the plugin does not modify). The functions must then be registered with the goa code generator tool using the "RegisterPlugin" function of the "codegen" package. This is typically done in a package "init" function, for example: The first argument of RegisterPlugin must be one of "gen" or "example" and specifies the "goa" command that triggers the call to the plugin functions. The second argument is the Prepare function if any, nil otherwise. The last argument is the code generator function if any, nil otherwise. A plugin may introduce new DSL "keywords" (typically Go package functions). The DSL functions initialize the content of a design root object (an object that implements the "eval.Root" interface), for example: The [eval](https://godoc.org/goa.design/goa/v3/codegen/eval) package contains a number of functions that can be leveraged to implement the DSL such as error reporting functions. The plugin design root object is then given to the plugin Generate function (if there's one) which may take advantage of it to generate the code.

Package goredis is another redis client with full features which writter in golang Protocol Specification: http://redis.io/topics/protocol. Redis reply has five types: status, error, integer, bulk, multi bulk. A Status Reply is in the form of a single line string starting with "+" terminated by "\r\n". Error Replies are very similar to Status Replies. The only difference is that the first byte is "-". Integer reply is just a CRLF terminated string representing an integer, prefixed by a ":" byte. Bulk replies are used by the server in order to return a single binary safe string up to 512 MB in length. A Multi bulk reply is used to return an array of other replies. Every element of a Multi Bulk Reply can be of any kind, including a nested Multi Bulk Reply. So five reply type is defined: And then a Reply struct which represent the redis response data is defined: Reply struct has many useful methods: Connect redis has two function: Dial and DialURL, for example: DialConfig can also take named options for connection config: Try a redis command is simple too, let's do GET/SET: Or you can execute customer command with Redis.ExecuteCommand method: Redis Pipelining is defined as: Transaction, Lua Eval, Publish/Subscribe, Monitor, Scan, Sort are also supported.