--- name: "AnyEvent::RipeRedis" section: "3pm" platform: "linux" package: "libanyevent-riperedis-perl" version: "0.48-3" release: "Debian 13 (Trixie)" platforms: ["linux"] url: "https://new.carta.tech/AnyEvent::RipeRedis" --- # AnyEvent::RipeRedis(3pm) Flexible non-blocking Redis client ## NAME AnyEvent::RipeRedis - Flexible non-blocking Redis client ## SYNOPSIS ``` use AnyEvent; use AnyEvent::RipeRedis; my $redis = AnyEvent::RipeRedis->new( host => 'localhost', port => 6379, password => 'yourpass', ); my $cv = AE::cv; $redis->set( 'foo', 'bar', sub { my $err = $_[1]; if ( defined $err ) { warn $err->message . "\n"; $cv->send; return; } $redis->get( 'foo', sub { my $reply = shift; my $err = shift; if ( defined $err ) { warn $err->message . "\n"; $cv->send; return; } print "$reply\n"; $cv->send; } ); } ); $cv->recv; ``` ## DESCRIPTION AnyEvent::RipeRedis is flexible non-blocking Redis client. Supports subscriptions, transactions and can automaticaly restore connection after failure. Requires Redis 1.2 or higher, and any supported event loop. ## CONSTRUCTOR ### new( %params ) ``` my $redis = AnyEvent::RipeRedis->new( host => 'localhost', port => 6379, password => 'yourpass', database => 7, connection_timeout => 5, read_timeout => 5, lazy => 1, reconnect_interval => 5, on_connect => sub { # handling... }, on_disconnect => sub { # handling... }, on_error => sub { my $err = shift; # error handling... }, ); ``` - host =\> $host Server hostname (default: 127.0.0.1) - port =\> $port Server port (default: 6379) - password =\> $password If the password is specified, the `"AUTH"` command is sent to the server after connection. - database =\> $index Database index. If the index is specified, the client switches to the specified database after connection. You can also switch to another database after connection by using `"SELECT"` command. The client remembers last selected database after reconnection and switches to it automaticaly. The default database index is `0`. - utf8 =\> $boolean If enabled, all strings will be converted to UTF-8 before sending to the server, and all results will be decoded from UTF-8. Enabled by default. - connection\_timeout =\> $fractional\_seconds Specifies connection timeout. If the client could not connect to the server after specified timeout, the `"on_error"` callback is called with the `"E_CANT_CONN"` error. The timeout specifies in seconds and can contain a fractional part. ``` connection_timeout => 10.5, ``` By default the client use kernel's connection timeout. - read\_timeout =\> $fractional\_seconds Specifies read timeout. If the client could not receive a reply from the server after specified timeout, the client close connection and call the `"on_error"` callback with the `"E_READ_TIMEDOUT"` error. The timeout is specifies in seconds and can contain a fractional part. ``` read_timeout => 3.5, ``` Not set by default. - lazy =\> $boolean If enabled, the connection establishes at time when you will send the first command to the server. By default the connection establishes after calling of the `"new"` method. Disabled by default. - reconnect =\> $boolean If the connection to the server was lost and the parameter `"reconnect"` is TRUE (default), the client will try to restore the connection when you execute next command. The client will try to reconnect only once and, if attempt fails, the error object is passed to command callback. If you need several attempts of the reconnection, you must retry a command from the callback as many times, as you need. Such behavior allows to control reconnection procedure. Enabled by default. - reconnect\_interval =\> $fractional\_seconds If the parameter is specified, the client will try to reconnect only after this interval. Commands executed between reconnections will be queued. ``` reconnect_interval => 5, ``` Not set by default. - handle\_params =\> \\%params Specifies AnyEvent::Handle parameters. ``` handle_params => { autocork => 1, linger => 60, } ``` Enabling of the `"autocork"` parameter can improve performance. See documentation on AnyEvent::Handle for more information. - on\_connect =\> $cb-\>() The `"on_connect"` callback is called when the connection is successfully established. Not set by default. - on\_disconnect =\> $cb-\>() The `"on_disconnect"` callback is called when the connection is closed by any reason. Not set by default. - on\_error =\> $cb-\>( $err ) The `"on_error"` callback is called when occurred an error, which was affected on entire client (e. g. connection error or authentication error). Also the `"on_error"` callback is called on command errors if the command callback is not specified. If the `"on_error"` callback is not specified, the client just print an error messages to `"STDERR"`. ## COMMAND EXECUTION ### \( \[ @args \] \[, $cb-\>( $reply, $err ) \] ) To execute the command you must call specific method with corresponding name. The reply to the command is passed to the callback in first argument. If any error occurred during the command execution, the error object is passed to the callback in second argument. Error object is the instance of the class AnyEvent::RipeRedis::Error. The command callback is optional. If it is not specified and any error occurred, the `"on_error"` callback of the client is called. The full list of the Redis commands can be found here: \. ``` $redis->get( 'foo', sub { my $reply = shift; my $err = shift; if ( defined $err ) { my $err_msg = $err->message; my $err_code = $err->code; # error handling... return; } print "$reply\n"; } ); $redis->lrange( 'list', 0, -1, sub { my $reply = shift; my $err = shift; if ( defined $err ) { my $err_msg = $err->message; my $err_code = $err->code; # error handling... return; } foreach my $value ( @{$reply} ) { print "$value\n"; } } ); $redis->incr( 'counter' ); ``` You can execute multi-word commands like this: ``` $redis->client_getname( sub { my $reply = shift; my $err = shift; if ( defined $err ) { my $err_msg = $err->message; my $err_code = $err->code; # error handling... return; } print "$reply\n"; } ); ``` ### execute( $command, \[ @args \] \[, $cb-\>( $reply, $err ) \] ) An alternative method to execute commands. In some cases it can be more convenient. ``` $redis->execute( 'get', 'foo', sub { my $reply = shift; my $err = shift; if ( defined $err ) { my $err_msg = $err->message; my $err_code = $err->code; return; } print "$reply\n"; } ); ``` ## TRANSACTIONS The detailed information about the Redis transactions can be found here: \. ### multi( \[ $cb-\>( $reply, $err ) \] ) Marks the start of a transaction block. Subsequent commands will be queued for atomic execution using `"EXEC"`. ### exec( \[ $cb-\>( $reply, $err ) \] ) Executes all previously queued commands in a transaction and restores the connection state to normal. When using `"WATCH"`, `"EXEC"` will execute commands only if the watched keys were not modified. If during a transaction at least one command fails, to the callback will be passed error object, and the reply will be contain nested error objects for every failed command. ``` $redis->multi(); $redis->set( 'foo', 'string' ); $redis->incr('foo'); # causes an error $redis->exec( sub { my $reply = shift; my $err = shift; if ( defined $err ) { my $err_msg = $err->message(); my $err_code = $err->code(); if ( defined $reply ) { foreach my $nested_reply ( @{$reply} ) { if ( ref($nested_reply) eq 'AnyEvent::RipeRedis::Error' ) { my $nested_err_msg = $nested_reply->message(); my $nested_err_code = $nested_reply->code(); # error handling... } } return; } # error handling... return; } # reply handling... }, ); ``` ### discard( \[ $cb-\>( $reply, $err ) \] ) Flushes all previously queued commands in a transaction and restores the connection state to normal. If `"WATCH"` was used, `"DISCARD"` unwatches all keys. ### watch( @keys \[, $cb-\>( $reply, $err ) \] ) Marks the given keys to be watched for conditional execution of a transaction. ### unwatch( \[ $cb-\>( $reply, $err ) \] ) Forget about all watched keys. ## SUBSCRIPTIONS Once the client enters the subscribed state it is not supposed to issue any other commands, except for additional `"SUBSCRIBE"`, `"PSUBSCRIBE"`, `"UNSUBSCRIBE"`, `"PUNSUBSCRIBE"` and `"QUIT"` commands. The detailed information about Redis Pub/Sub can be found here: \ ### subscribe( @channels, ( $cb-\>( $msg, $channel ) \| \\%cbs ) ) Subscribes the client to the specified channels. Method can accept two callbacks: `"on_reply"` and `"on_message"`. The `"on_reply"` callback is called when subscription to all specified channels will be activated. In first argument to the callback is passed the number of channels we are currently subscribed. If subscription to specified channels was lost, the `"on_reply"` callback is called with the error object in the second argument. The `"on_message"` callback is called on every published message. If the `"subscribe"` method is called with one callback, this callback will be act as `"on_message"` callback. ``` $redis->subscribe( qw( foo bar ), { on_reply => sub { my $channels_num = shift; my $err = shift; if ( defined $err ) { # error handling... return; } # reply handling... }, on_message => sub { my $msg = shift; my $channel = shift; # message handling... }, } ); $redis->subscribe( qw( foo bar ), sub { my $msg = shift; my $channel = shift; # message handling... } ); ``` ### psubscribe( @patterns, ( $cb-\>( $msg, $pattern, $channel ) \| \\%cbs ) ) Subscribes the client to the given patterns. See `subscribe()` method for details. ``` $redis->psubscribe( qw( foo_* bar_* ), { on_reply => sub { my $channels_num = shift; my $err = shift; if ( defined $err ) { # error handling... return; } # reply handling... }, on_message => sub { my $msg = shift; my $pattern = shift; my $channel = shift; # message handling... }, } ); $redis->psubscribe( qw( foo_* bar_* ), sub { my $msg = shift; my $pattern = shift; my $channel = shift; # message handling... } ); ``` ### publish( $channel, $message \[, $cb-\>( $reply, $err ) \] ) Posts a message to the given channel. ### unsubscribe( \[ @channels \] \[, $cb-\>( $reply, $err ) \] ) Unsubscribes the client from the given channels, or from all of them if none is given. In first argument to the callback is passed the number of channels we are currently subscribed or zero if we were unsubscribed from all channels. ``` $redis->unsubscribe( qw( foo bar ), sub { my $channels_num = shift; my $err = shift; if ( defined $err ) { # error handling... return; } # reply handling... } ); ``` ### punsubscribe( \[ @patterns \] \[, $cb-\>( $reply, $err ) \] ) Unsubscribes the client from the given patterns, or from all of them if none is given. See `unsubscribe()` method for details. ``` $redis->punsubscribe( qw( foo_* bar_* ), sub { my $channels_num = shift; my $err = shift; if ( defined $err ) { # error handling... return; } # reply handling... } ); ``` ## CONNECTION VIA UNIX-SOCKET Redis 2.2 and higher support connection via UNIX domain socket. To connect via a UNIX-socket in the parameter `"host"` you have to specify `"unix/"`, and in the parameter `"port"` you have to specify the path to the socket. ``` my $redis = AnyEvent::RipeRedis->new( host => 'unix/', port => '/tmp/redis.sock', ); ``` ## LUA SCRIPTS EXECUTION Redis 2.6 and higher support execution of Lua scripts on the server side. To execute a Lua script you can send one of the commands `"EVAL"` or `"EVALSHA"`, or use the special method `eval_cached()`. ### eval\_cached( $script, $keys\_num \[, @keys \] \[, @args \] \[, $cb-\>( $reply, $err ) \] \] ); When you call the `eval_cached()` method, the client first generate a SHA1 hash for a Lua script and cache it in memory. Then the client optimistically send the `"EVALSHA"` command under the hood. If the `"E_NO_SCRIPT"` error will be returned, the client send the `"EVAL"` command. If you call the `eval_cached()` method with the same Lua script, client don not generate a SHA1 hash for this script repeatedly, it gets a hash from the cache instead. ``` $redis->eval_cached( 'return { KEYS[1], KEYS[2], ARGV[1], ARGV[2] }', 2, 'key1', 'key2', 'first', 'second', sub { my $reply = shift; my $err = shift; if ( defined $err ) { # error handling... return; } foreach my $value ( @{$reply} ) { print "$value\n"; } } ); ``` Be care, passing a different Lua scripts to `eval_cached()` method every time cause memory leaks. If Lua script returns multi-bulk reply with at least one error reply, to the callback will be passed error object, and the reply will be contain nested error objects. ``` $redis->eval_cached( "return { 'foo', redis.error_reply( 'Error.' ) }", 0, sub { my $reply = shift; my $err = shift; if ( defined $err ) { my $err_msg = $err->message; my $err_code = $err->code; if ( defined $reply ) { foreach my $nested_reply ( @{$reply} ) { if ( ref($nested_reply) eq 'AnyEvent::RipeRedis::Error' ) { my $nested_err_msg = $nested_reply->message(); my $nested_err_code = $nested_reply->code(); # error handling... } } } # error handling... return; } # reply handling... } ); ``` ## ERROR CODES Every error object, passed to callback, contain error code, which can be used for programmatic handling of errors. AnyEvent::RipeRedis provides constants for error codes. They can be imported and used in expressions. ``` use AnyEvent::RipeRedis qw( :err_codes ); ``` - E\_CANT\_CONN Can't connect to the server. All operations were aborted. - E\_LOADING\_DATASET Redis is loading the dataset in memory. - E\_IO Input/Output operation error. The connection to the Redis server was closed and all operations were aborted. - E\_CONN\_CLOSED\_BY\_REMOTE\_HOST The connection closed by remote host. All operations were aborted. - E\_CONN\_CLOSED\_BY\_CLIENT Connection closed by client prematurely. Uncompleted operations were aborted. - E\_NO\_CONN No connection to the Redis server. Connection was lost by any reason on previous operation. - E\_OPRN\_ERROR Operation error. For example, wrong number of arguments for a command. - E\_UNEXPECTED\_DATA The client received unexpected reply from the server. The connection to the Redis server was closed and all operations were aborted. - E\_READ\_TIMEDOUT Read timed out. The connection to the Redis server was closed and all operations were aborted. Error codes available since Redis 2.6. - E\_NO\_SCRIPT No matching script. Use the `"EVAL"` command. - E\_BUSY Redis is busy running a script. You can only call `"SCRIPT KILL"` or `"SHUTDOWN NOSAVE"`. - E\_NOT\_BUSY No scripts in execution right now. - E\_MASTER\_DOWN Link with MASTER is down and slave-serve-stale-data is set to 'no'. - E\_MISCONF Redis is configured to save RDB snapshots, but is currently not able to persist on disk. Commands that may modify the data set are disabled. Please check Redis logs for details about the error. - E\_READONLY You can't write against a read only slave. - E\_OOM Command not allowed when used memory \> 'maxmemory'. - E\_EXEC\_ABORT Transaction discarded because of previous errors. Error codes available since Redis 2.8. - E\_NO\_AUTH Authentication required. - E\_WRONG\_TYPE Operation against a key holding the wrong kind of value. - E\_NO\_REPLICAS Not enough good slaves to write. - E\_BUSY\_KEY Target key name already exists. Error codes available since Redis 3.0. - E\_CROSS\_SLOT Keys in request don't hash to the same slot. - E\_TRY\_AGAIN Multiple keys request during rehashing of slot. - E\_ASK Redirection required. For more information see: \ - E\_MOVED Redirection required. For more information see: \ - E\_CLUSTER\_DOWN The cluster is down or hash slot not served. ## DISCONNECTION When the connection to the server is no longer needed you can close it in three ways: call the method `disconnect()`, send the `"QUIT"` command or you can just "forget" any references to an AnyEvent::RipeRedis object, but in this case the client object is destroyed without calling any callbacks, including the `"on_disconnect"` callback, to avoid an unexpected behavior. ### disconnect() The method for synchronous disconnection. All uncompleted operations will be aborted. ### quit( \[ $cb-\>( $reply, $err ) \] ) The method for asynchronous disconnection. ## OTHER METHODS ### info( \[ $section \] \[, $cb-\>( $reply, $err ) \] ) Gets and parses information and statistics about the server. The result is passed to callback as a hash reference. More information about `"INFO"` command can be found here: \ ### host() Gets current host of the client. ### port() Gets current port of the client. ### select( $index, \[, $cb-\>( $reply, $err ) \] ) Selects the database by numeric index. ### database() Gets selected database index. ### utf8( \[ $boolean \] ) Enables or disables UTF-8 mode. ### connection\_timeout( \[ $fractional\_seconds \] ) Gets or sets the `"connection_timeout"` of the client. The `"undef"` value resets the `"connection_timeout"` to default value. ### read\_timeout( \[ $fractional\_seconds \] ) Gets or sets the `"read_timeout"` of the client. ### reconnect( \[ $boolean \] ) Enables or disables reconnection mode of the client. ### reconnect\_interval( \[ $fractional\_seconds \] ) Gets or sets `"reconnect_interval"` of the client. ### on\_connect( \[ $callback \] ) Gets or sets the `"on_connect"` callback. ### on\_disconnect( \[ $callback \] ) Gets or sets the `"on_disconnect"` callback. ### on\_error( \[ $callback \] ) Gets or sets the `"on_error"` callback. ## SEE ALSO AnyEvent::RipeRedis::Cluster, AnyEvent, Redis::hiredis, Redis, RedisDB ## AUTHOR Eugene Ponizovsky, \ Sponsored by SMS Online, \ ### Special thanks - • Alexey Shrub - • Vadim Vlasov - • Konstantin Uvarin - • Ivan Kruglov ## COPYRIGHT AND LICENSE Copyright (c) 2012-2021, Eugene Ponizovsky, SMS Online. All rights reserved. This module is free software; you can redistribute it and/or modify it under the same terms as Perl itself.