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github.com/snowflakedb/gosnowflake

Package gosnowflake is a pure Go Snowflake driver for the database/sql package. Clients can use the database/sql package directly. For example: Use the Open() function to create a database handle with connection parameters: The Go Snowflake Driver supports the following connection syntaxes (or data source name (DSN) formats): where all parameters must be escaped or use Config and DSN to construct a DSN string. For information about account identifiers, see the Snowflake documentation (https://docs.snowflake.com/en/user-guide/admin-account-identifier.html). The following example opens a database handle with the Snowflake account named "my_account" under the organization named "my_organization", where the username is "jsmith", password is "mypassword", database is "mydb", schema is "testschema", and warehouse is "mywh": The connection string (DSN) can contain both connection parameters (described below) and session parameters (https://docs.snowflake.com/en/sql-reference/parameters.html). The following connection parameters are supported: account <string>: Specifies your Snowflake account, where "<string>" is the account identifier assigned to your account by Snowflake. For information about account identifiers, see the Snowflake documentation (https://docs.snowflake.com/en/user-guide/admin-account-identifier.html). If you are using a global URL, then append the connection group and ".global" (e.g. "<account_identifier>-<connection_group>.global"). The account identifier and the connection group are separated by a dash ("-"), as shown above. This parameter is optional if your account identifier is specified after the "@" character in the connection string. region <string>: DEPRECATED. You may specify a region, such as "eu-central-1", with this parameter. However, since this parameter is deprecated, it is best to specify the region as part of the account parameter. For details, see the description of the account parameter. database: Specifies the database to use by default in the client session (can be changed after login). schema: Specifies the database schema to use by default in the client session (can be changed after login). warehouse: Specifies the virtual warehouse to use by default for queries, loading, etc. in the client session (can be changed after login). role: Specifies the role to use by default for accessing Snowflake objects in the client session (can be changed after login). passcode: Specifies the passcode provided by Duo when using multi-factor authentication (MFA) for login. passcodeInPassword: false by default. Set to true if the MFA passcode is embedded in the login password. Appends the MFA passcode to the end of the password. loginTimeout: Specifies the timeout, in seconds, for login. The default is 60 seconds. The login request gives up after the timeout length if the HTTP response is success. requestTimeout: Specifies the timeout, in seconds, for a query to complete. 0 (zero) specifies that the driver should wait indefinitely. The default is 0 seconds. The query request gives up after the timeout length if the HTTP response is success. authenticator: Specifies the authenticator to use for authenticating user credentials: To use the internal Snowflake authenticator, specify snowflake (Default). If you want to cache your MFA logins, use AuthTypeUsernamePasswordMFA authenticator. To authenticate through Okta, specify https://<okta_account_name>.okta.com (URL prefix for Okta). To authenticate using your IDP via a browser, specify externalbrowser. To authenticate via OAuth, specify oauth and provide an OAuth Access Token (see the token parameter below). application: Identifies your application to Snowflake Support. insecureMode: false by default. Set to true to bypass the Online Certificate Status Protocol (OCSP) certificate revocation check. IMPORTANT: Change the default value for testing or emergency situations only. token: a token that can be used to authenticate. Should be used in conjunction with the "oauth" authenticator. client_session_keep_alive: Set to true have a heartbeat in the background every hour to keep the connection alive such that the connection session will never expire. Care should be taken in using this option as it opens up the access forever as long as the process is alive. ocspFailOpen: true by default. Set to false to make OCSP check fail closed mode. validateDefaultParameters: true by default. Set to false to disable checks on existence and privileges check for Database, Schema, Warehouse and Role when setting up the connection tracing: Specifies the logging level to be used. Set to error by default. Valid values are trace, debug, info, print, warning, error, fatal, panic. disableQueryContextCache: disables parsing of query context returned from server and resending it to server as well. Default value is false. clientConfigFile: specifies the location of the client configuration json file. In this file you can configure Easy Logging feature. disableSamlURLCheck: disables the SAML URL check. Default value is false. All other parameters are interpreted as session parameters (https://docs.snowflake.com/en/sql-reference/parameters.html). For example, the TIMESTAMP_OUTPUT_FORMAT session parameter can be set by adding: A complete connection string looks similar to the following: Session-level parameters can also be set by using the SQL command "ALTER SESSION" (https://docs.snowflake.com/en/sql-reference/sql/alter-session.html). Alternatively, use OpenWithConfig() function to create a database handle with the specified Config. # Connection Config You can also connect to your warehouse using the connection config. The dbSql library states that when you want to take advantage of driver-specific connection features that aren’t available in a connection string. Each driver supports its own set of connection properties, often providing ways to customize the connection request specific to the DBMS For example: If you are using this method, you dont need to pass a driver name to specify the driver type in which you are looking to connect. Since the driver name is not needed, you can optionally bypass driver registration on startup. To do this, set `GOSNOWFLAKE_SKIP_REGISTERATION` in your environment. This is useful you wish to register multiple verions of the driver. Note: GOSNOWFLAKE_SKIP_REGISTERATION should not be used if sql.Open() is used as the method to connect to the server, as sql.Open will require registration so it can map the driver name to the driver type, which in this case is "snowflake" and SnowflakeDriver{}. You can load the connnection configuration with .toml file format. With two environment variables SNOWFLAKE_HOME(connections.toml file directory) SNOWFLAKE_DEFAULT_CONNECTION_NAME(DSN name), the driver will search the config file and load the connection. You can find how to use this connection way at ./cmd/tomlfileconnection or Snowflake doc: https://docs.snowflake.com/en/developer-guide/snowflake-cli-v2/connecting/specify-credentials The Go Snowflake Driver honors the environment variables HTTP_PROXY, HTTPS_PROXY and NO_PROXY for the forward proxy setting. NO_PROXY specifies which hostname endings should be allowed to bypass the proxy server, e.g. no_proxy=.amazonaws.com means that Amazon S3 access does not need to go through the proxy. NO_PROXY does not support wildcards. Each value specified should be one of the following: The end of a hostname (or a complete hostname), for example: ".amazonaws.com" or "xy12345.snowflakecomputing.com". An IP address, for example "192.196.1.15". If more than one value is specified, values should be separated by commas, for example: By default, the driver's builtin logger is exposing logrus's FieldLogger and default at INFO level. Users can use SetLogger in driver.go to set a customized logger for gosnowflake package. In order to enable debug logging for the driver, user could use SetLogLevel("debug") in SFLogger interface as shown in demo code at cmd/logger.go. To redirect the logs SFlogger.SetOutput method could do the work. A custom query tag can be set in the context. Each query run with this context will include the custom query tag as metadata that will appear in the Query Tag column in the Query History log. For example: A specific query request ID can be set in the context and will be passed through in place of the default randomized request ID. For example: If you need query ID for your query you have to use raw connection. For queries: ``` ``` For execs: ``` ``` The result of your query can be retrieved by setting the query ID in the WithFetchResultByID context. ``` ``` From 0.5.0, a signal handling responsibility has moved to the applications. If you want to cancel a query/command by Ctrl+C, add a os.Interrupt trap in context to execute methods that can take the context parameter (e.g. QueryContext, ExecContext). See cmd/selectmany.go for the full example. The Go Snowflake Driver now supports the Arrow data format for data transfers between Snowflake and the Golang client. The Arrow data format avoids extra conversions between binary and textual representations of the data. The Arrow data format can improve performance and reduce memory consumption in clients. Snowflake continues to support the JSON data format. The data format is controlled by the session-level parameter GO_QUERY_RESULT_FORMAT. To use JSON format, execute: The valid values for the parameter are: If the user attempts to set the parameter to an invalid value, an error is returned. The parameter name and the parameter value are case-insensitive. This parameter can be set only at the session level. Usage notes: The Arrow data format reduces rounding errors in floating point numbers. You might see slightly different values for floating point numbers when using Arrow format than when using JSON format. In order to take advantage of the increased precision, you must pass in the context.Context object provided by the WithHigherPrecision function when querying. Traditionally, the rows.Scan() method returned a string when a variable of types interface was passed in. Turning on the flag ENABLE_HIGHER_PRECISION via WithHigherPrecision will return the natural, expected data type as well. For some numeric data types, the driver can retrieve larger values when using the Arrow format than when using the JSON format. For example, using Arrow format allows the full range of SQL NUMERIC(38,0) values to be retrieved, while using JSON format allows only values in the range supported by the Golang int64 data type. Users should ensure that Golang variables are declared using the appropriate data type for the full range of values contained in the column. For an example, see below. When using the Arrow format, the driver supports more Golang data types and more ways to convert SQL values to those Golang data types. The table below lists the supported Snowflake SQL data types and the corresponding Golang data types. The columns are: The SQL data type. The default Golang data type that is returned when you use snowflakeRows.Scan() to read data from Arrow data format via an interface{}. The possible Golang data types that can be returned when you use snowflakeRows.Scan() to read data from Arrow data format directly. The default Golang data type that is returned when you use snowflakeRows.Scan() to read data from JSON data format via an interface{}. (All returned values are strings.) The standard Golang data type that is returned when you use snowflakeRows.Scan() to read data from JSON data format directly. Go Data Types for Scan() =================================================================================================================== | ARROW | JSON =================================================================================================================== SQL Data Type | Default Go Data Type | Supported Go Data | Default Go Data Type | Supported Go Data | for Scan() interface{} | Types for Scan() | for Scan() interface{} | Types for Scan() =================================================================================================================== BOOLEAN | bool | string | bool ------------------------------------------------------------------------------------------------------------------- VARCHAR | string | string ------------------------------------------------------------------------------------------------------------------- DOUBLE | float32, float64 [1] , [2] | string | float32, float64 ------------------------------------------------------------------------------------------------------------------- INTEGER that | int, int8, int16, int32, int64 | string | int, int8, int16, fits in int64 | [1] , [2] | | int32, int64 ------------------------------------------------------------------------------------------------------------------- INTEGER that doesn't | int, int8, int16, int32, int64, *big.Int | string | error fit in int64 | [1] , [2] , [3] , [4] | ------------------------------------------------------------------------------------------------------------------- NUMBER(P, S) | float32, float64, *big.Float | string | float32, float64 where S > 0 | [1] , [2] , [3] , [5] | ------------------------------------------------------------------------------------------------------------------- DATE | time.Time | string | time.Time ------------------------------------------------------------------------------------------------------------------- TIME | time.Time | string | time.Time ------------------------------------------------------------------------------------------------------------------- TIMESTAMP_LTZ | time.Time | string | time.Time ------------------------------------------------------------------------------------------------------------------- TIMESTAMP_NTZ | time.Time | string | time.Time ------------------------------------------------------------------------------------------------------------------- TIMESTAMP_TZ | time.Time | string | time.Time ------------------------------------------------------------------------------------------------------------------- BINARY | []byte | string | []byte ------------------------------------------------------------------------------------------------------------------- ARRAY [6] | string / array | string / array ------------------------------------------------------------------------------------------------------------------- OBJECT [6] | string / struct | string / struct ------------------------------------------------------------------------------------------------------------------- VARIANT | string | string ------------------------------------------------------------------------------------------------------------------- MAP | map | map [1] Converting from a higher precision data type to a lower precision data type via the snowflakeRows.Scan() method can lose low bits (lose precision), lose high bits (completely change the value), or result in error. [2] Attempting to convert from a higher precision data type to a lower precision data type via interface{} causes an error. [3] Higher precision data types like *big.Int and *big.Float can be accessed by querying with a context returned by WithHigherPrecision(). [4] You cannot directly Scan() into the alternative data types via snowflakeRows.Scan(), but can convert to those data types by using .Int64()/.String()/.Uint64() methods. For an example, see below. [5] You cannot directly Scan() into the alternative data types via snowflakeRows.Scan(), but can convert to those data types by using .Float32()/.String()/.Float64() methods. For an example, see below. [6] Arrays and objects can be either semistructured or structured, see more info in section below. Note: SQL NULL values are converted to Golang nil values, and vice-versa. Snowflake supports two flavours of "structured data" - semistructured and structured. Semistructured types are variants, objects and arrays without schema. When data is fetched, it's represented as strings and the client is responsible for its interpretation. Example table definition: The data not have any corresponding schema, so values in table may be slightly different. Semistuctured variants, objects and arrays are always represented as strings for scanning: When inserting, a marker indicating correct type must be used, for example: Structured types differentiate from semistructured types by having specific schema. In all rows of the table, values must conform to this schema. Example table definition: To retrieve structured objects, follow these steps: 1. Create a struct implementing sql.Scanner interface, example: a) b) Automatic scan goes through all fields in a struct and read object fields. Struct fields have to be public. Embedded structs have to be pointers. Matching name is built using struct field name with first letter lowercase. Additionally, `sf` tag can be added: - first value is always a name of a field in an SQL object - additionally `ignore` parameter can be passed to omit this field 2. Use WithStructuredTypesEnabled context while querying data. 3. Use it in regular scan: See StructuredObject for all available operations including null support, embedding nested structs, etc. Retrieving array of simple types works exactly the same like normal values - using Scan function. You can use WithMapValuesNullable and WithArrayValuesNullable contexts to handle null values in, respectively, maps and arrays of simple types in the database. In that case, sql null types will be used: If you want to scan array of structs, you have to use a helper function ScanArrayOfScanners: Retrieving structured maps is very similar to retrieving arrays: To bind structured objects use: 1. Create a type which implements a StructuredObjectWriter interface, example: a) b) 2. Use an instance as regular bind. 3. If you need to bind nil value, use special syntax: Binding structured arrays are like any other parameter. The only difference is - if you want to insert empty array (not nil but empty), you have to use: The following example shows how to retrieve very large values using the math/big package. This example retrieves a large INTEGER value to an interface and then extracts a big.Int value from that interface. If the value fits into an int64, then the code also copies the value to a variable of type int64. Note that a context that enables higher precision must be passed in with the query. If the variable named "rows" is known to contain a big.Int, then you can use the following instead of scanning into an interface and then converting to a big.Int: If the variable named "rows" contains a big.Int, then each of the following fails: Similar code and rules also apply to big.Float values. If you are not sure what data type will be returned, you can use code similar to the following to check the data type of the returned value: You can retrieve data in a columnar format similar to the format a server returns, without transposing them to rows. When working with the arrow columnar format in go driver, ArrowBatch structs are used. These are structs mostly corresponding to data chunks received from the backend. They allow for access to specific arrow.Record structs. An ArrowBatch can exist in a state where the underlying data has not yet been loaded. The data is downloaded and translated only on demand. Translation options are retrieved from a context.Context interface, which is either passed from query context or set by the user using WithContext(ctx) method. In order to access them you must use `WithArrowBatches` context, similar to the following: This returns []*ArrowBatch. ArrowBatch functions: GetRowCount(): Returns the number of rows in the ArrowBatch. Note that this returns 0 if the data has not yet been loaded, irrespective of it’s actual size. WithContext(ctx context.Context): Sets the context of the ArrowBatch to the one provided. Note that the context will not retroactively apply to data that has already been downloaded. For example: will produce the same result in records1 and records2, irrespective of the newly provided ctx. Context worth noting are: -WithArrowBatchesTimestampOption -WithHigherPrecision -WithArrowBatchesUtf8Validation described in more detail later. Fetch(): Returns the underlying records as *[]arrow.Record. When this function is called, the ArrowBatch checks whether the underlying data has already been loaded, and downloads it if not. Limitations: How to handle timestamps in Arrow batches: Snowflake returns timestamps natively (from backend to driver) in multiple formats. The Arrow timestamp is an 8-byte data type, which is insufficient to handle the larger date and time ranges used by Snowflake. Also, Snowflake supports 0-9 (nanosecond) digit precision for seconds, while Arrow supports only 3 (millisecond), 6 (microsecond), an 9 (nanosecond) precision. Consequently, Snowflake uses a custom timestamp format in Arrow, which differs on timestamp type and precision. If you want to use timestamps in Arrow batches, you have two options: How to handle invalid UTF-8 characters in Arrow batches: Snowflake previously allowed users to upload data with invalid UTF-8 characters. Consequently, Arrow records containing string columns in Snowflake could include these invalid UTF-8 characters. However, according to the Arrow specifications (https://arrow.apache.org/docs/cpp/api/datatype.html and https://github.com/apache/arrow/blob/a03d957b5b8d0425f9d5b6c98b6ee1efa56a1248/go/arrow/datatype.go#L73-L74), Arrow string columns should only contain UTF-8 characters. To address this issue and prevent potential downstream disruptions, the context WithArrowBatchesUtf8Validation, is introduced. When enabled, this feature iterates through all values in string columns, identifying and replacing any invalid characters with `�`. This ensures that Arrow records conform to the UTF-8 standards, preventing validation failures in downstream services like the Rust Arrow library that impose strict validation checks. How to handle higher precision in Arrow batches: To preserve BigDecimal values within Arrow batches, use WithHigherPrecision. This offers two main benefits: it helps avoid precision loss and defers the conversion to upstream services. Alternatively, without this setting, all non-zero scale numbers will be converted to float64, potentially resulting in loss of precision. Zero-scale numbers (DECIMAL256, DECIMAL128) will be converted to int64, which could lead to overflow. Binding allows a SQL statement to use a value that is stored in a Golang variable. Without binding, a SQL statement specifies values by specifying literals inside the statement. For example, the following statement uses the literal value “42“ in an UPDATE statement: With binding, you can execute a SQL statement that uses a value that is inside a variable. For example: The “?“ inside the “VALUES“ clause specifies that the SQL statement uses the value from a variable. Binding data that involves time zones can require special handling. For details, see the section titled "Timestamps with Time Zones". Version 1.6.23 (and later) of the driver takes advantage of sql.Null types which enables the proper handling of null parameters inside function calls, i.e.: The timestamp nullability had to be achieved by wrapping the sql.NullTime type as the Snowflake provides several date and time types which are mapped to single Go time.Time type: Version 1.3.9 (and later) of the Go Snowflake Driver supports the ability to bind an array variable to a parameter in a SQL INSERT statement. You can use this technique to insert multiple rows in a single batch. As an example, the following code inserts rows into a table that contains integer, float, boolean, and string columns. The example binds arrays to the parameters in the INSERT statement. If the array contains SQL NULL values, use slice []interface{}, which allows Golang nil values. This feature is available in version 1.6.12 (and later) of the driver. For example, For slices []interface{} containing time.Time values, a binding parameter flag is required for the preceding array variable in the Array() function. This feature is available in version 1.6.13 (and later) of the driver. For example, Note: For alternative ways to load data into the Snowflake database (including bulk loading using the COPY command), see Loading Data into Snowflake (https://docs.snowflake.com/en/user-guide-data-load.html). When you use array binding to insert a large number of values, the driver can improve performance by streaming the data (without creating files on the local machine) to a temporary stage for ingestion. The driver automatically does this when the number of values exceeds a threshold (no changes are needed to user code). In order for the driver to send the data to a temporary stage, the user must have the following privilege on the schema: If the user does not have this privilege, the driver falls back to sending the data with the query to the Snowflake database. In addition, the current database and schema for the session must be set. If these are not set, the CREATE TEMPORARY STAGE command executed by the driver can fail with the following error: For alternative ways to load data into the Snowflake database (including bulk loading using the COPY command), see Loading Data into Snowflake (https://docs.snowflake.com/en/user-guide-data-load.html). Go's database/sql package supports the ability to bind a parameter in a SQL statement to a time.Time variable. However, when the client binds data to send to the server, the driver cannot determine the correct Snowflake date/timestamp data type to associate with the binding parameter. For example: To resolve this issue, a binding parameter flag is introduced that associates any subsequent time.Time type to the DATE, TIME, TIMESTAMP_LTZ, TIMESTAMP_NTZ or BINARY data type. The above example could be rewritten as follows: The driver fetches TIMESTAMP_TZ (timestamp with time zone) data using the offset-based Location types, which represent a collection of time offsets in use in a geographical area, such as CET (Central European Time) or UTC (Coordinated Universal Time). The offset-based Location data is generated and cached when a Go Snowflake Driver application starts, and if the given offset is not in the cache, it is generated dynamically. Currently, Snowflake does not support the name-based Location types (e.g. "America/Los_Angeles"). For more information about Location types, see the Go documentation for https://golang.org/pkg/time/#Location. Internally, this feature leverages the []byte data type. As a result, BINARY data cannot be bound without the binding parameter flag. In the following example, sf is an alias for the gosnowflake package: The driver directly downloads a result set from the cloud storage if the size is large. It is required to shift workloads from the Snowflake database to the clients for scale. The download takes place by goroutine named "Chunk Downloader" asynchronously so that the driver can fetch the next result set while the application can consume the current result set. The application may change the number of result set chunk downloader if required. Note this does not help reduce memory footprint by itself. Consider Custom JSON Decoder. Custom JSON Decoder for Parsing Result Set (Experimental) The application may have the driver use a custom JSON decoder that incrementally parses the result set as follows. This option will reduce the memory footprint to half or even quarter, but it can significantly degrade the performance depending on the environment. The test cases running on Travis Ubuntu box show five times less memory footprint while four times slower. Be cautious when using the option. The Go Snowflake Driver supports JWT (JSON Web Token) authentication. To enable this feature, construct the DSN with fields "authenticator=SNOWFLAKE_JWT&privateKey=<your_private_key>", or using a Config structure specifying: The <your_private_key> should be a base64 URL encoded PKCS8 rsa private key string. One way to encode a byte slice to URL base 64 URL format is through the base64.URLEncoding.EncodeToString() function. On the server side, you can alter the public key with the SQL command: The <your_public_key> should be a base64 Standard encoded PKI public key string. One way to encode a byte slice to base 64 Standard format is through the base64.StdEncoding.EncodeToString() function. To generate the valid key pair, you can execute the following commands in the shell: Note: As of February 2020, Golang's official library does not support passcode-encrypted PKCS8 private key. For security purposes, Snowflake highly recommends that you store the passcode-encrypted private key on the disk and decrypt the key in your application using a library you trust. JWT tokens are recreated on each retry and they are valid (`exp` claim) for `jwtTimeout` seconds. Each retry timeout is configured by `jwtClientTimeout`. Retries are limited by total time of `loginTimeout`. The driver allows to authenticate using the external browser. When a connection is created, the driver will open the browser window and ask the user to sign in. To enable this feature, construct the DSN with field "authenticator=EXTERNALBROWSER" or using a Config structure with following Authenticator specified: The external browser authentication implements timeout mechanism. This prevents the driver from hanging interminably when browser window was closed, or not responding. Timeout defaults to 120s and can be changed through setting DSN field "externalBrowserTimeout=240" (time in seconds) or using a Config structure with following ExternalBrowserTimeout specified: This feature is available in version 1.3.8 or later of the driver. By default, Snowflake returns an error for queries issued with multiple statements. This restriction helps protect against SQL Injection attacks (https://en.wikipedia.org/wiki/SQL_injection). The multi-statement feature allows users skip this restriction and execute multiple SQL statements through a single Golang function call. However, this opens up the possibility for SQL injection, so it should be used carefully. The risk can be reduced by specifying the exact number of statements to be executed, which makes it more difficult to inject a statement by appending it. More details are below. The Go Snowflake Driver provides two functions that can execute multiple SQL statements in a single call: To compose a multi-statement query, simply create a string that contains all the queries, separated by semicolons, in the order in which the statements should be executed. To protect against SQL Injection attacks while using the multi-statement feature, pass a Context that specifies the number of statements in the string. For example: When multiple queries are executed by a single call to QueryContext(), multiple result sets are returned. After you process the first result set, get the next result set (for the next SQL statement) by calling NextResultSet(). The following pseudo-code shows how to process multiple result sets: The function db.ExecContext() returns a single result, which is the sum of the number of rows changed by each individual statement. For example, if your multi-statement query executed two UPDATE statements, each of which updated 10 rows, then the result returned would be 20. Individual row counts for individual statements are not available. The following code shows how to retrieve the result of a multi-statement query executed through db.ExecContext(): Note: Because a multi-statement ExecContext() returns a single value, you cannot detect offsetting errors. For example, suppose you expected the return value to be 20 because you expected each UPDATE statement to update 10 rows. If one UPDATE statement updated 15 rows and the other UPDATE statement updated only 5 rows, the total would still be 20. You would see no indication that the UPDATES had not functioned as expected. The ExecContext() function does not return an error if passed a query (e.g. a SELECT statement). However, it still returns only a single value, not a result set, so using it to execute queries (or a mix of queries and non-query statements) is impractical. The QueryContext() function does not return an error if passed non-query statements (e.g. DML). The function returns a result set for each statement, whether or not the statement is a query. For each non-query statement, the result set contains a single row that contains a single column; the value is the number of rows changed by the statement. If you want to execute a mix of query and non-query statements (e.g. a mix of SELECT and DML statements) in a multi-statement query, use QueryContext(). You can retrieve the result sets for the queries, and you can retrieve or ignore the row counts for the non-query statements. Note: PUT statements are not supported for multi-statement queries. If a SQL statement passed to ExecQuery() or QueryContext() fails to compile or execute, that statement is aborted, and subsequent statements are not executed. Any statements prior to the aborted statement are unaffected. For example, if the statements below are run as one multi-statement query, the multi-statement query fails on the third statement, and an exception is thrown. If you then query the contents of the table named "test", the values 1 and 2 would be present. When using the QueryContext() and ExecContext() functions, golang code can check for errors the usual way. For example: Preparing statements and using bind variables are also not supported for multi-statement queries. The Go Snowflake Driver supports asynchronous execution of SQL statements. Asynchronous execution allows you to start executing a statement and then retrieve the result later without being blocked while waiting. While waiting for the result of a SQL statement, you can perform other tasks, including executing other SQL statements. Most of the steps to execute an asynchronous query are the same as the steps to execute a synchronous query. However, there is an additional step, which is that you must call the WithAsyncMode() function to update your Context object to specify that asynchronous mode is enabled. In the code below, the call to "WithAsyncMode()" is specific to asynchronous mode. The rest of the code is compatible with both asynchronous mode and synchronous mode. The function db.QueryContext() returns an object of type snowflakeRows regardless of whether the query is synchronous or asynchronous. However: The call to the Next() function of snowflakeRows is always synchronous (i.e. blocking). If the query has not yet completed and the snowflakeRows object (named "rows" in this example) has not been filled in yet, then rows.Next() waits until the result set has been filled in. More generally, calls to any Golang SQL API function implemented in snowflakeRows or snowflakeResult are blocking calls, and wait if results are not yet available. (Examples of other synchronous calls include: snowflakeRows.Err(), snowflakeRows.Columns(), snowflakeRows.columnTypes(), snowflakeRows.Scan(), and snowflakeResult.RowsAffected().) Because the example code above executes only one query and no other activity, there is no significant difference in behavior between asynchronous and synchronous behavior. The differences become significant if, for example, you want to perform some other activity after the query starts and before it completes. The example code below starts a query, which run in the background, and then retrieves the results later. This example uses small SELECT statements that do not retrieve enough data to require asynchronous handling. However, the technique works for larger data sets, and for situations where the programmer might want to do other work after starting the queries and before retrieving the results. For a more elaborative example please see cmd/async/async.go The Go Snowflake Driver supports the PUT and GET commands. The PUT command copies a file from a local computer (the computer where the Golang client is running) to a stage on the cloud platform. The GET command copies data files from a stage on the cloud platform to a local computer. See the following for information on the syntax and supported parameters: Using PUT: The following example shows how to run a PUT command by passing a string to the db.Query() function: "<local_file>" should include the file path as well as the name. Snowflake recommends using an absolute path rather than a relative path. For example: Different client platforms (e.g. linux, Windows) have different path name conventions. Ensure that you specify path names appropriately. This is particularly important on Windows, which uses the backslash character as both an escape character and as a separator in path names. To send information from a stream (rather than a file) use code similar to the code below. (The ReplaceAll() function is needed on Windows to handle backslashes in the path to the file.) Note: PUT statements are not supported for multi-statement queries. Using GET: The following example shows how to run a GET command by passing a string to the db.Query() function: "<local_file>" should include the file path as well as the name. Snowflake recommends using an absolute path rather than a relative path. For example: To download a file into an in-memory stream (rather than a file) use code similar to the code below. Note: GET statements are not supported for multi-statement queries. Specifying temporary directory for encryption and compression: Putting and getting requires compression and/or encryption, which is done in the OS temporary directory. If you cannot use default temporary directory for your OS or you want to specify it yourself, you can use "tmpDirPath" DSN parameter. Remember, to encode slashes. Example: Using custom configuration for PUT/GET: If you want to override some default configuration options, you can use `WithFileTransferOptions` context. There are multiple config parameters including progress bars or compression.

v1.12.0 • 3 weeks ago

github.com/horriblename/lf

lf is a terminal file manager. Source code can be found in the repository at https://github.com/gokcehan/lf This documentation can either be read from terminal using 'lf -doc' or online at https://pkg.go.dev/github.com/gokcehan/lf You can also use 'doc' command (default '<f-1>') inside lf to view the documentation in a pager. A man page with the same content is also available in the repository at https://github.com/gokcehan/lf/blob/master/lf.1 You can run 'lf -help' to see descriptions of command line options. The following commands are provided by lf: The following command line commands are provided by lf: The following options can be used to customize the behavior of lf: The following environment variables are exported for shell commands: The following special shell commands are used to customize the behavior of lf when defined: The following commands/keybindings are provided by default: The following additional keybindings are provided by default: If the 'mouse' option is enabled, mouse buttons have the following default effects: Configuration files should be located at: Colors file should be located at: Icons file should be located at: Selection file should be located at: Marks file should be located at: Tags file should be located at: History file should be located at: You can configure these locations with the following variables given with their order of precedences and their default values: A sample configuration file can be found at https://github.com/gokcehan/lf/blob/master/etc/lfrc.example This section shows information about builtin commands. Modal commands do not take any arguments, but instead change the operation mode to read their input conveniently, and so they are meant to be assigned to keybindings. Quit lf and return to the shell. Move/scroll the current file selection upwards/downwards by one/half a page/full page. Change the current working directory to the parent directory. If the current file is a directory, then change the current directory to it, otherwise, execute the 'open' command. A default 'open' command is provided to call the default system opener asynchronously with the current file as the argument. A custom 'open' command can be defined to override this default. Change the current working directory to the next/previous jumplist item. Move the current file selection to the top/bottom of the directory. A count can be specified to move to a specific line, for example use `3G` to move to the third line. Move the current file selection to the high/middle/low of the screen. Toggle the selection of the current file or files given as arguments. Reverse the selection of all files in the current directory (i.e. 'toggle' all files). Selections in other directories are not effected by this command. You can define a new command to select all files in the directory by combining 'invert' with 'unselect' (i.e. 'cmd select-all :unselect; invert'), though this will also remove selections in other directories. Reverse the selection (i.e. 'toggle') of all files at or after the current file in the current directory. To select a contiguous block of files, use this command on the first file you want to select. Then, move down to the first file you do *not* want to select (the one after the end of the desired selection) and use this command again. This achieves an effect similar to the visual mode in vim. This command is experimental and may be removed once a better replacement for the visual mode is implemented in 'lf'. If you'd like to experiment with using this command, you should bind it to a key (e.g. 'V') for a better experience. Remove the selection of all files in all directories. Select/unselect files that match the given glob. Calculate the total size for each of the selected directories. Option 'info' should include 'size' and option 'dircounts' should be disabled to show this size. If the total size of a directory is not calculated, it will be shown as '-'. Remove all keybindings associated with the `map` command. This command can be used in the config file to remove the default keybindings. For safety purposes, `:` is left mapped to the `read` command, and `cmap` keybindings are retained so that it is still possible to exit `lf` using `:quit`. If there are no selections, save the path of the current file to the copy buffer, otherwise, copy the paths of selected files. If there are no selections, save the path of the current file to the cut buffer, otherwise, copy the paths of selected files. Copy/Move files in copy/cut buffer to the current working directory. A custom 'paste' command can be defined to override this default. Clear file paths in copy/cut buffer. Synchronize copied/cut files with server. This command is automatically called when required. Draw the screen. This command is automatically called when required. Synchronize the terminal and redraw the screen. Load modified files and directories. This command is automatically called when required. Flush the cache and reload all files and directories. Print given arguments to the message line at the bottom. Print given arguments to the message line at the bottom and also to the log file. Print given arguments to the message line at the bottom as 'errorfmt' and also to the log file. Change the working directory to the given argument. Change the current file selection to the given argument. Remove the current file or selected file(s). A custom 'delete' command can be defined to override this default. Rename the current file using the builtin method. A custom 'rename' command can be defined to override this default. Read the configuration file given in the argument. Simulate key pushes given in the argument. Read a command to evaluate. Read a shell command to execute. Read a shell command to execute piping its standard I/O to the bottom statline. Read a shell command to execute and wait for a key press in the end. Read a shell command to execute asynchronously without standard I/O. Read key(s) to find the appropriate file name match in the forward/backward direction and jump to the next/previous match. Read a pattern to search for a file name match in the forward/backward direction and jump to the next/previous match. Command 'filter' reads a pattern to filter out and only view files matching the pattern. Command 'setfilter' does the same but uses an argument to set the filter immediately. You can supply an argument to 'filter', in order to use that as the starting prompt. Save the current directory as a bookmark assigned to the given key. Change the current directory to the bookmark assigned to the given key. A special bookmark "'" holds the previous directory after a 'mark-load', 'cd', or 'select' command. Remove a bookmark assigned to the given key. Tag a file with '*' or a single width character given in the argument. You can define a new tag clearing command by combining 'tag' with 'tag-toggle' (i.e. 'cmd tag-clear :tag; tag-toggle'). Tag a file with '*' or a single width character given in the argument if the file is untagged, otherwise remove the tag. The prompt character specifies which of the several command-line modes you are in. For example, the 'read' command takes you to the ':' mode. When the cursor is at the first character in ':' mode, pressing one of the keys '!', '$', '%', or '&' takes you to the corresponding mode. You can go back with 'cmd-delete-back' ('<backspace>' by default). The command line commands should be mostly compatible with readline keybindings. A character refers to a unicode code point, a word consists of letters and digits, and a unix word consists of any non-blank characters. Quit command line mode and return to normal mode. Autocomplete the current word. Autocomplete the current word with menu selection. You need to assign keys to these commands (e.g. 'cmap <tab> cmd-menu-complete; cmap <backtab> cmd-menu-complete-back'). You can use the assigned keys assigned to display the menu and then cycle through completion options. Accept the currently selected match in menu completion and close the menu. Execute the current line. Interrupt the current shell-pipe command and return to the normal mode. Go to next/previous item in the history. Move the cursor to the left/right. Move the cursor to the beginning/end of line. Delete the next character. Delete the previous character. When at the beginning of a prompt, returns either to normal mode or to ':' mode. Delete everything up to the beginning/end of line. Delete the previous unix word. Paste the buffer content containing the last deleted item. Transpose the positions of last two characters/words. Move the cursor by one word in forward/backward direction. Delete the next word in forward direction. Capitalize/uppercase/lowercase the current word and jump to the next word. List all key mappings in normal mode or command-line editing mode. List all custom commands defined using the `cmd` command List the contents of the jump list, in order of the most recently visited locations. Each location is marked with the count that can be used with the `jump-prev` and `jump-next` commands (e.g. use `3[` to move three spaces backwards in the jump list). A '>' is used to mark the current location in the jump list. This section shows information about options to customize the behavior. Character ':' is used as the separator for list options '[]int' and '[]string'. When this option is enabled, find command starts matching patterns from the beginning of file names, otherwise, it can match at an arbitrary position. Automatically quit server when there are no clients left connected. Format string of the box drawing characters enabled by the `drawbox` option. Set the path of a cleaner file. The file should be executable. This file is called if previewing is enabled, the previewer is set, and the previously selected file had its preview cache disabled. The following arguments are passed to the file, (1) current file name, (2) width, (3) height, (4) horizontal position, (5) vertical position of preview pane and (6) next file name to be previewed respectively. Preview cleaning is disabled when the value of this option is left empty. Format strings for highlighting the cursor. `cursoractivefmt` applies in the current directory pane, `cursorparentfmt` applies in panes that show parents of the current directory, and `cursorpreviewfmt` applies in panes that preview directories. The default is to make the active cursor and the parent directory cursor inverted. The preview cursor is underlined. Some other possibilities to consider for the preview or parent cursors: an empty string for no cursor, "\033[7;2m" for dimmed inverted text (visibility varies by terminal), "\033[7;90m" for inverted text with grey (aka "brightblack") background. If the format string contains the characters `%s`, it is interpreted as a format string for `fmt.Sprintf`. Such a string should end with the terminal reset sequence. For example, "\033[4m%s\033[0m" has the same effect as "\033[4m". Cache directory contents. When this option is enabled, directory sizes show the number of items inside instead of the total size of the directory, which needs to be calculated for each directory using 'calcdirsize'. This information needs to be calculated by reading the directory and counting the items inside. Therefore, this option is disabled by default for performance reasons. This option only has an effect when 'info' has a 'size' field and the pane is wide enough to show the information. 999 items are counted per directory at most, and bigger directories are shown as '999+'. Show directories first above regular files. Show only directories. If enabled, directories will also be passed to the previewer script. This allows custom previews for directories. Draw boxes around panes with box drawing characters. Format string of file name when creating duplicate files. With the default format, copying a file `abc.txt` to the same directory will result in a duplicate file called `abc.txt.~1~`. Special expansions are provided, '%f' as the file name, '%b' for basename (file name without extension), '%e' as the extension (including the dot) and '%n' as the number of duplicates. Format string of error messages shown in the bottom message line. If the format string contains the characters `%s`, it is interpreted as a format string for `fmt.Sprintf`. Such a string should end with the terminal reset sequence. For example, "\033[4m%s\033[0m" has the same effect as "\033[4m". File separator used in environment variables 'fs' and 'fx'. Number of characters prompted for the find command. When this value is set to 0, find command prompts until there is only a single match left. When this option is enabled, search command patterns are considered as globs, otherwise they are literals. With globbing, '*' matches any sequence, '?' matches any character, and '[...]' or '[^...]' matches character sets or ranges. Otherwise, these characters are interpreted as they are. Show hidden files. On Unix systems, hidden files are determined by the value of 'hiddenfiles'. On Windows, only files with hidden attributes are considered hidden files. List of hidden file glob patterns. Patterns can be given as relative or absolute paths. Globbing supports the usual special characters, '*' to match any sequence, '?' to match any character, and '[...]' or '[^...]' to match character sets or ranges. In addition, if a pattern starts with '!', then its matches are excluded from hidden files. To add multiple patterns, use ':' as a separator. Example: '.*:lost+found:*.bak' Save command history. Show icons before each item in the list. Sets 'IFS' variable in shell commands. It works by adding the assignment to the beginning of the command string as "IFS='...'; ...". The reason is that 'IFS' variable is not inherited by the shell for security reasons. This method assumes a POSIX shell syntax and so it can fail for non-POSIX shells. This option has no effect when the value is left empty. This option does not have any effect on Windows. Ignore case in sorting and search patterns. Ignore diacritics in sorting and search patterns. Jump to the first match after each keystroke during searching. Apply filter pattern after each keystroke during filtering. List of information shown for directory items at the right side of pane. Currently supported information types are 'size', 'time', 'atime', and 'ctime'. Information is only shown when the pane width is more than twice the width of information. Format string of the file time shown in the info column when it matches this year. Format string of the file time shown in the info column when it doesn't match this year. Send mouse events as input. Show the position number for directory items at the left side of pane. When 'relativenumber' option is enabled, only the current line shows the absolute position and relative positions are shown for the rest. Format string of the position number for each line. Set the interval in seconds for periodic checks of directory updates. This works by periodically calling the 'load' command. Note that directories are already updated automatically in many cases. This option can be useful when there is an external process changing the displayed directory and you are not doing anything in lf. Periodic checks are disabled when the value of this option is set to zero. List of attributes that are preserved when copying files. Currently supported attributes are 'mode' (i.a. access mode) and 'timestamps' (i.e. modification time and access time). Note: Preserving other attribute like ownership of change/birth timestamp is desireable, but not portably supported in go. Show previews of files and directories at the right most pane. If the file has more lines than the preview pane, rest of the lines are not read. Files containing the null character (U+0000) in the read portion are considered binary files and displayed as 'binary'. Set the path of a previewer file to filter the content of regular files for previewing. The file should be executable. The following arguments are passed to the file, (1) current file name, (2) width, (3) height, (4) horizontal position, and (5) vertical position of preview pane respectively. SIGPIPE signal is sent when enough lines are read. If the previewer returns a non-zero exit code, then the preview cache for the given file is disabled. This means that if the file is selected in the future, the previewer is called once again. Preview filtering is disabled and files are displayed as they are when the value of this option is left empty. Format string of the prompt shown in the top line. Special expansions are provided, '%u' as the user name, '%h' as the host name, '%w' as the working directory, '%d' as the working directory with a trailing path separator, '%f' as the file name, and '%F' as the current filter. '%S' may be used once and will provide a spacer so that the following parts are right aligned on the screen. Home folder is shown as '~' in the working directory expansion. Directory names are automatically shortened to a single character starting from the left most parent when the prompt does not fit to the screen. List of ratios of pane widths. Number of items in the list determines the number of panes in the ui. When 'preview' option is enabled, the right most number is used for the width of preview pane. Show the position number relative to the current line. When 'number' is enabled, current line shows the absolute position, otherwise nothing is shown. Reverse the direction of sort. List of information shown in status line ruler. Currently supported information types are 'acc', 'progress', 'selection', 'filter', 'ind', 'df' and names starting with 'lf_'. `acc` shows the pressed keys (e.g. for bindings with multiple key presses or counts given to bindings). `progress` shows the progress of file operations (e.g. copying a large directory). `selection` shows the number of files that are selected, or designated for being cut/copied. `filter` shows 'F' if a filter is currently being applied. `ind` shows the current position of the cursor as well as the number of files in the current directory. `df` shows the amount of free disk space remaining. Names starting with `lf_` show the value of environment variables exported by lf. This is useful for displaying the current settings (e.g. `lf_selmode` displays the current setting for the `selmode` option). User defined options starting with `lf_user_` are also supported, so it is possible to display information set from external sources. Selection mode for commands. When set to 'all' it will use the selected files from all directories. When set to 'dir' it will only use the selected files in the current directory. Minimum number of offset lines shown at all times in the top and the bottom of the screen when scrolling. The current line is kept in the middle when this option is set to a large value that is bigger than the half of number of lines. A smaller offset can be used when the current file is close to the beginning or end of the list to show the maximum number of items. Shell executable to use for shell commands. Shell commands are executed as 'shell shellopts shellflag command -- arguments'. Command line flag used to pass shell commands. List of shell options to pass to the shell executable. Override 'ignorecase' option when the pattern contains an uppercase character. This option has no effect when 'ignorecase' is disabled. Override 'ignoredia' option when the pattern contains a character with diacritic. This option has no effect when 'ignoredia' is disabled. Sort type for directories. Currently supported sort types are 'natural', 'name', 'size', 'time', 'ctime', 'atime', and 'ext'. Format string of the file info shown in the bottom left corner. Special expansions are provided, '%p' as the file permissions, '%c' as the link count, '%u' as the user, '%g' as the group, '%s' as the file size, '%t' as the last modified time, and '%l' as the link target. The `|` character splits the format string into sections. Any section containing a failed expansion (result is a blank string) is discarded and not shown. Number of space characters to show for horizontal tabulation (U+0009) character. Format string of the tags. If the format string contains the characters `%s`, it is interpreted as a format string for `fmt.Sprintf`. Such a string should end with the terminal reset sequence. For example, "\033[4m%s\033[0m" has the same effect as "\033[4m". Marks to be considered temporary (e.g. 'abc' refers to marks 'a', 'b', and 'c'). These marks are not synced to other clients and they are not saved in the bookmarks file. Note that the special bookmark "'" is always treated as temporary and it does not need to be specified. Format string of the file modification time shown in the bottom line. Truncate character shown at the end when the file name does not fit to the pane. When a filename is too long to be shown completely, the available space is partitioned in two pieces. truncatepct defines a fraction (in percent between 0 and 100) for the size of the first piece, which will show the beginning of the filename. The second piece will show the end of the filename and will use the rest of the available space. Both pieces are separated by the truncation character (truncatechar). A value of 100 will only show the beginning of the filename, while a value of 0 will only show the end of the filename, e.g.: - `set truncatepct 100` -> "very-long-filename-tr~" (default) - `set truncatepct 50` -> "very-long-f~-truncated" - `set truncatepct 0` -> "~ng-filename-truncated" String shown after commands of shell-wait type. Searching can wrap around the file list. Scrolling can wrap around the file list. Any option that is prefixed with 'user_' is a user defined option and can be set to any string. Inside a user defined command the value will be provided in the `lf_user_{option}` environment variable. These options are not used by lf and are not persisted. The following variables are exported for shell commands: These are referred with a '$' prefix on POSIX shells (e.g. '$f'), between '%' characters on Windows cmd (e.g. '%f%'), and with a '$env:' prefix on Windows powershell (e.g. '$env:f'). Current file selection as a full path. Selected file(s) separated with the value of 'filesep' option as full path(s). Selected file(s) (i.e. 'fs') if there are any selected files, otherwise current file selection (i.e. 'f'). Id of the running client. Present working directory. Initial working directory. The value of this variable is set to the current nesting level when you run lf from a shell spawned inside lf. You can add the value of this variable to your shell prompt to make it clear that your shell runs inside lf. For example, with POSIX shells, you can use '[ -n "$LF_LEVEL" ] && PS1="$PS1""(lf level: $LF_LEVEL) "' in your shell configuration file (e.g. '~/.bashrc'). If this variable is set in the environment, use the same value. Otherwise, this is set to 'start' in Windows, 'open' in MacOS, 'xdg-open' in others. If VISUAL is set in the environment, use its value. Otherwise, use the value of the environment variable EDITOR. If neither variable is set, this is set to 'vi' on Unix, 'notepad' in Windows. If this variable is set in the environment, use the same value. Otherwise, this is set to 'less' on Unix, 'more' in Windows. If this variable is set in the environment, use the same value. Otherwise, this is set to 'sh' on Unix, 'cmd' in Windows. Absolute path to the currently running lf binary, if it can be found. Otherwise, this is set to the string 'lf'. Value of the {option}. Value of the user_{option}. Width/Height of the terminal. Value of the count associated with the current command. This section shows information about special shell commands. This shell command can be defined to override the default 'open' command when the current file is not a directory. This shell command can be defined to override the default 'paste' command. This shell command can be defined to override the default 'rename' command. This shell command can be defined to override the default 'delete' command. This shell command can be defined to be executed before changing a directory. This shell command can be defined to be executed after changing a directory. This shell command can be defined to be executed after the selection changes. This shell command can be defined to be executed before quit. The following command prefixes are used by lf: The same evaluator is used for the command line and the configuration file for read and shell commands. The difference is that prefixes are not necessary in the command line. Instead, different modes are provided to read corresponding commands. These modes are mapped to the prefix keys above by default. Characters from '#' to newline are comments and ignored: There are four special commands ('set', 'map', 'cmap', and 'cmd') for configuration. Command 'set' is used to set an option which can be boolean, integer, or string: Command 'map' is used to bind a key to a command which can be builtin command, custom command, or shell command: Command 'cmap' is used to bind a key on the command line to a command line command or any other command: You can delete an existing binding by leaving the expression empty: Command 'cmd' is used to define a custom command: You can delete an existing command by leaving the expression empty: If there is no prefix then ':' is assumed: An explicit ':' can be provided to group statements until a newline which is especially useful for 'map' and 'cmd' commands: If you need multiline you can wrap statements in '{{' and '}}' after the proper prefix. Regular keys are assigned to a command with the usual syntax: Keys combined with the shift key simply use the uppercase letter: Special keys are written in between '<' and '>' characters and always use lowercase letters: Angle brackets can be assigned with their special names: Function keys are prefixed with 'f' character: Keys combined with the control key are prefixed with 'c' character: Keys combined with the alt key are assigned in two different ways depending on the behavior of your terminal. Older terminals (e.g. xterm) may set the 8th bit of a character when the alt key is pressed. On these terminals, you can use the corresponding byte for the mapping: Newer terminals (e.g. gnome-terminal) may prefix the key with an escape key when the alt key is pressed. lf uses the escape delaying mechanism to recognize alt keys in these terminals (delay is 100ms). On these terminals, keys combined with the alt key are prefixed with 'a' character: It is possible to combine special keys with modifiers: WARNING: Some key combinations will likely be intercepted by your OS, window manager, or terminal. Other key combinations cannot be recognized by lf due to the way terminals work (e.g. `Ctrl+h` combination sends a backspace key instead). The easiest way to find out the name of a key combination and whether it will work on your system is to press the key while lf is running and read the name from the "unknown mapping" error. Mouse buttons are prefixed with 'm' character: Mouse wheel events are also prefixed with 'm' character: The usual way to map a key sequence is to assign it to a named or unnamed command. While this provides a clean way to remap builtin keys as well as other commands, it can be limiting at times. For this reason 'push' command is provided by lf. This command is used to simulate key pushes given as its arguments. You can 'map' a key to a 'push' command with an argument to create various keybindings. This is mainly useful for two purposes. First, it can be used to map a command with a command count: Second, it can be used to avoid typing the name when a command takes arguments: One thing to be careful is that since 'push' command works with keys instead of commands it is possible to accidentally create recursive bindings: These types of bindings create a deadlock when executed. Regular shell commands are the most basic command type that is useful for many purposes. For example, we can write a shell command to move selected file(s) to trash. A first attempt to write such a command may look like this: We check '$fs' to see if there are any selected files. Otherwise we just delete the current file. Since this is such a common pattern, a separate '$fx' variable is provided. We can use this variable to get rid of the conditional: The trash directory is checked each time the command is executed. We can move it outside of the command so it would only run once at startup: Since these are one liners, we can drop '{{' and '}}': Finally note that we set 'IFS' variable manually in these commands. Instead we could use the 'ifs' option to set it for all shell commands (i.e. 'set ifs "\n"'). This can be especially useful for interactive use (e.g. '$rm $f' or '$rm $fs' would simply work). This option is not set by default as it can behave unexpectedly for new users. However, use of this option is highly recommended and it is assumed in the rest of the documentation. Regular shell commands have some limitations in some cases. When an output or error message is given and the command exits afterwards, the ui is immediately resumed and there is no way to see the message without dropping to shell again. Also, even when there is no output or error, the ui still needs to be paused while the command is running. This can cause flickering on the screen for short commands and similar distractions for longer commands. Instead of pausing the ui, piping shell commands connects stdin, stdout, and stderr of the command to the statline in the bottom of the ui. This can be useful for programs following the Unix philosophy to give no output in the success case, and brief error messages or prompts in other cases. For example, following rename command prompts for overwrite in the statline if there is an existing file with the given name: You can also output error messages in the command and it will show up in the statline. For example, an alternative rename command may look like this: Note that input is line buffered and output and error are byte buffered. Waiting shell commands are similar to regular shell commands except that they wait for a key press when the command is finished. These can be useful to see the output of a program before the ui is resumed. Waiting shell commands are more appropriate than piping shell commands when the command is verbose and the output is best displayed as multiline. Asynchronous shell commands are used to start a command in the background and then resume operation without waiting for the command to finish. Stdin, stdout, and stderr of the command is neither connected to the terminal nor to the ui. One of the more advanced features in lf is remote commands. All clients connect to a server on startup. It is possible to send commands to all or any of the connected clients over the common server. This is used internally to notify file selection changes to other clients. To use this feature, you need to use a client which supports communicating with a Unix domain socket. OpenBSD implementation of netcat (nc) is one such example. You can use it to send a command to the socket file: Since such a client may not be available everywhere, lf comes bundled with a command line flag to be used as such. When using lf, you do not need to specify the address of the socket file. This is the recommended way of using remote commands since it is shorter and immune to socket file address changes: In this command 'send' is used to send the rest of the string as a command to all connected clients. You can optionally give it an id number to send a command to a single client: All clients have a unique id number but you may not be aware of the id number when you are writing a command. For this purpose, an '$id' variable is exported to the environment for shell commands. The value of this variable is set to the process id of the client. You can use it to send a remote command from a client to the server which in return sends a command back to itself. So now you can display a message in the current client by calling the following in a shell command: Since lf does not have control flow syntax, remote commands are used for such needs. For example, you can configure the number of columns in the ui with respect to the terminal width as follows: Besides 'send' command, there is a 'quit' command to quit the server when there are no connected clients left, and a 'quit!' command to force quit the server by closing client connections first: Lastly, there is a 'conn' command to connect the server as a client. This should not be needed for users. lf uses its own builtin copy and move operations by default. These are implemented as asynchronous operations and progress is shown in the bottom ruler. These commands do not overwrite existing files or directories with the same name. Instead, a suffix that is compatible with '--backup=numbered' option in GNU cp is added to the new files or directories. Only file modes and (some) timestamps can be preserved (see `preserve` option), all other attributes are ignored including ownership, context, and xattr. Special files such as character and block devices, named pipes, and sockets are skipped and links are not followed. Moving is performed using the rename operation of the underlying OS. For cross-device moving, lf falls back to copying and then deletes the original files if there are no errors. Operation errors are shown in the message line as well as the log file and they do not preemptively finish the corresponding file operation. File operations can be performed on the current selected file or alternatively on multiple files by selecting them first. When you 'copy' a file, lf doesn't actually copy the file on the disk, but only records its name to a file. The actual file copying takes place when you 'paste'. Similarly 'paste' after a 'cut' operation moves the file. You can customize copy and move operations by defining a 'paste' command. This is a special command that is called when it is defined instead of the builtin implementation. You can use the following example as a starting point: Some useful things to be considered are to use the backup ('--backup') and/or preserve attributes ('-a') options with 'cp' and 'mv' commands if they support it (i.e. GNU implementation), change the command type to asynchronous, or use 'rsync' command with progress bar option for copying and feed the progress to the client periodically with remote 'echo' calls. By default, lf does not assign 'delete' command to a key to protect new users. You can customize file deletion by defining a 'delete' command. You can also assign a key to this command if you like. An example command to move selected files to a trash folder and remove files completely after a prompt are provided in the example configuration file. There are two mechanisms implemented in lf to search a file in the current directory. Searching is the traditional method to move the selection to a file matching a given pattern. Finding is an alternative way to search for a pattern possibly using fewer keystrokes. Searching mechanism is implemented with commands 'search' (default '/'), 'search-back' (default '?'), 'search-next' (default 'n'), and 'search-prev' (default 'N'). You can enable 'globsearch' option to match with a glob pattern. Globbing supports '*' to match any sequence, '?' to match any character, and '[...]' or '[^...] to match character sets or ranges. You can enable 'incsearch' option to jump to the current match at each keystroke while typing. In this mode, you can either use 'cmd-enter' to accept the search or use 'cmd-escape' to cancel the search. You can also map some other commands with 'cmap' to accept the search and execute the command immediately afterwards. For example, you can use the right arrow key to finish the search and open the selected file with the following mapping: Finding mechanism is implemented with commands 'find' (default 'f'), 'find-back' (default 'F'), 'find-next' (default ';'), 'find-prev' (default ','). You can disable 'anchorfind' option to match a pattern at an arbitrary position in the filename instead of the beginning. You can set the number of keys to match using 'findlen' option. If you set this value to zero, then the the keys are read until there is only a single match. Default values of these two options are set to jump to the first file with the given initial. Some options effect both searching and finding. You can disable 'wrapscan' option to prevent searches to wrap around at the end of the file list. You can disable 'ignorecase' option to match cases in the pattern and the filename. This option is already automatically overridden if the pattern contains upper case characters. You can disable 'smartcase' option to disable this behavior. Two similar options 'ignoredia' and 'smartdia' are provided to control matching diacritics in latin letters. You can define a an 'open' command (default 'l' and '<right>') to configure file opening. This command is only called when the current file is not a directory, otherwise the directory is entered instead. You can define it just as you would define any other command: It is possible to use different command types: You may want to use either file extensions or mime types from 'file' command: You may want to use 'setsid' before your opener command to have persistent processes that continue to run after lf quits. Regular shell commands (i.e. '$') drop to terminal which results in a flicker for commands that finishes immediately (e.g. 'xdg-open' in the above example). If you want to use asynchronous shell commands (i.e. '&') but also want to use the terminal when necessary (e.g. 'vi' in the above exxample), you can use a remote command: Note, asynchronous shell commands run in their own process group by default so they do not require the manual use of 'setsid'. Following command is provided by default: You may also use any other existing file openers as you like. Possible options are 'libfile-mimeinfo-perl' (executable name is 'mimeopen'), 'rifle' (ranger's default file opener), or 'mimeo' to name a few. lf previews files on the preview pane by printing the file until the end or the preview pane is filled. This output can be enhanced by providing a custom preview script for filtering. This can be used to highlight source codes, list contents of archive files or view pdf or image files to name a few. For coloring lf recognizes ansi escape codes. In order to use this feature you need to set the value of 'previewer' option to the path of an executable file. Five arguments are passed to the file, (1) current file name, (2) width, (3) height, (4) horizontal position, and (5) vertical position of preview pane respectively. Output of the execution is printed in the preview pane. You may also want to use the same script in your pager mapping as well: For 'less' pager, you may instead utilize 'LESSOPEN' mechanism so that useful information about the file such as the full path of the file can still be displayed in the statusline below: Since this script is called for each file selection change it needs to be as efficient as possible and this responsibility is left to the user. You may use file extensions to determine the type of file more efficiently compared to obtaining mime types from 'file' command. Extensions can then be used to match cleanly within a conditional: Another important consideration for efficiency is the use of programs with short startup times for preview. For this reason, 'highlight' is recommended over 'pygmentize' for syntax highlighting. Besides, it is also important that the application is processing the file on the fly rather than first reading it to the memory and then do the processing afterwards. This is especially relevant for big files. lf automatically closes the previewer script output pipe with a SIGPIPE when enough lines are read. When everything else fails, you can make use of the height argument to only feed the first portion of the file to a program for preview. Note that some programs may not respond well to SIGPIPE to exit with a non-zero return code and avoid caching. You may add a trailing '|| true' command to avoid such errors: You may also use an existing preview filter as you like. Your system may already come with a preview filter named 'lesspipe'. These filters may have a mechanism to add user customizations as well. See the related documentations for more information. lf changes the working directory of the process to the current directory so that shell commands always work in the displayed directory. After quitting, it returns to the original directory where it is first launched like all shell programs. If you want to stay in the current directory after quitting, you can use one of the example lfcd wrapper shell scripts provided in the repository at https://github.com/gokcehan/lf/tree/master/etc There is a special command 'on-cd' that runs a shell command when it is defined and the directory is changed. You can define it just as you would define any other command: If you want to print escape sequences, you may redirect 'printf' output to '/dev/tty'. The following xterm specific escape sequence sets the terminal title to the working directory: This command runs whenever you change directory but not on startup. You can add an extra call to make it run on startup as well: Note that all shell commands are possible but '%' and '&' are usually more appropriate as '$' and '!' causes flickers and pauses respectively. There is also a 'pre-cd' command, that works like 'on-cd', but is run before the directory is actually changed. lf tries to automatically adapt its colors to the environment. It starts with a default colorscheme and updates colors using values of existing environment variables possibly by overwriting its previous values. Colors are set in the following order: Please refer to the corresponding man pages for more information about 'LSCOLORS' and 'LS_COLORS'. 'LF_COLORS' is provided with the same syntax as 'LS_COLORS' in case you want to configure colors only for lf but not ls. This can be useful since there are some differences between ls and lf, though one should expect the same behavior for common cases. Colors file is provided for easier configuration without environment variables. This file should consist of whitespace separated pairs with '#' character to start comments until the end of line. You can configure lf colors in two different ways. First, you can only configure 8 basic colors used by your terminal and lf should pick up those colors automatically. Depending on your terminal, you should be able to select your colors from a 24-bit palette. This is the recommended approach as colors used by other programs will also match each other. Second, you can set the values of environment variables or colors file mentioned above for fine grained customization. Note that 'LS_COLORS/LF_COLORS' are more powerful than 'LSCOLORS' and they can be used even when GNU programs are not installed on the system. You can combine this second method with the first method for best results. Lastly, you may also want to configure the colors of the prompt line to match the rest of the colors. Colors of the prompt line can be configured using the 'promptfmt' option which can include hardcoded colors as ansi escapes. See the default value of this option to have an idea about how to color this line. It is worth noting that lf uses as many colors advertised by your terminal's entry in terminfo or infocmp databases on your system. If an entry is not present, it falls back to an internal database. If your terminal supports 24-bit colors but either does not have a database entry or does not advertise all capabilities, you can enable support by setting the '$COLORTERM' variable to 'truecolor' or ensuring '$TERM' is set to a value that ends with '-truecolor'. Default lf colors are mostly taken from GNU dircolors defaults. These defaults use 8 basic colors and bold attribute. Default dircolors entries with background colors are simplified to avoid confusion with current file selection in lf. Similarly, there are only file type matchings and extension matchings are left out for simplicity. Default values are as follows given with their matching order in lf: Note that lf first tries matching file names and then falls back to file types. The full order of matchings from most specific to least are as follows: For example, given a regular text file '/path/to/README.txt', the following entries are checked in the configuration and the first one to match is used: Given a regular directory '/path/to/example.d', the following entries are checked in the configuration and the first one to match is used: Note that glob-like patterns do not actually perform glob matching due to performance reasons. For example, you can set a variable as follows: Having all entries on a single line can make it hard to read. You may instead divide it to multiple lines in between double quotes by escaping newlines with backslashes as follows: Having such a long variable definition in a shell configuration file might be undesirable. You may instead use the colors file for configuration. A sample colors file can be found at https://github.com/gokcehan/lf/blob/master/etc/colors.example You may also see the wiki page for ansi escape codes https://en.wikipedia.org/wiki/ANSI_escape_code Icons are configured using 'LF_ICONS' environment variable or an icons file. The variable uses the same syntax as 'LS_COLORS/LF_COLORS'. Instead of colors, you should put a single characters as values of entries. Icons file should consist of whitespace separated pairs with '#' character to start comments until the end of line. Do not forget to enable 'icons' option to see the icons. Default values are as follows given with their matching order in lf: A sample icons file can be found at https://github.com/gokcehan/lf/blob/master/etc/icons.example

v0.0.0-20231002120534-741dd48f1031 • last year

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Progress Bar

gopkg.in/cheggaaa/pb.v1

github.com/cheggaaa/pb

github.com/vbauerster/mpb/v7

github.com/vbauerster/mpb

github.com/vbauerster/mpb/v4

github.com/gosuri/uiprogress

github.com/vbauerster/mpb/v5

github.com/vbauerster/mpb/v6

github.com/vbauerster/mpb/v8

github.com/snowflakedb/gosnowflake

github.com/tj/go-progress

github.com/tinyming-go/progress-bar-go

github.com/Gauchemoss/Project-progress-bar

pkg.re/cheggaaa/pb.v1

github.com/Gosuri/uiprogress

gopkg.in/vbauerster/mpb.v2

gopkg.in/vbauerster/mpb.v1

gopkg.in/vbauerster/mpb.v4

gopkg.in/vbauerster/mpb.v3

gopkg.in/vbauerster/mpb.v5

github.com/ermanimer/progress_bar

github.com/vardius/progress-go

github.com/Kei-K23/spinix

github.com/bibelin/taskbar

github.com/davidsnyder/uiprogress

github.com/claustra01/typetalk-progress-bar-bot

github.com/stelmanjones/termtools/progress

github.com/GordonFremen/gosnowflake

github.com/releaseband/go-progress-bar

github.com/mintoolkit/uiprogress

github.com/brigand/ink-progress-bar

github.com/edouard-lopez/progress-bar.sh

github.com/meloalright/vue-ins-progress-bar

git.sr.ht/~liliace/pogs

github.com/sfreiberg/progress

github.com/deepin-community/golang-gopkg-cheggaaa-pb.v1

github.com/elulcao/progress-bar

github.com/nozo-moto/anci_progress_bar

github.com/zminfra/uiprogress

github.com/c-darwin/pb

github.com/papacharlie/go-progress-bar

github.com/skyqvn/progress_bar

github.com/corentindeboisset/styledconsole

github.com/horriblename/lf

github.com/wux1an/mpb/v7

github.com/etowah/uiprogress

gitee.com/shirdonl/goProgressor

github.com/devshorts/uiprogress

github.com/YiFangtao/pb

github.com/duyunzhi/progress_bar