README

NAME

    ngx_redis2 - Nginx upstream module for the Redis 2.0 protocol

    *This module is not distributed with the Nginx source.* See the
        installation instructions.

STATUS
    This module is still under development and is considered experimental.

SYNOPSIS

    location /foo {
        set $value 'first';
        redis2_query set one $value;
        redis2_pass 127.0.0.1:6379;
    }

    # GET /get?key=some_key
    location /get {
        set_unescape_uri $key $arg_key;  # this requires ngx_set_misc
        redis2_query get $key;
        redis2_pass foo.com:6379;
    }

    # GET /set?key=one&val=first%20value
    location /set {
        set_unescape_uri $key $arg_key;  # this requires ngx_set_misc
        set_unescape_uri $val $arg_val;  # this requires ngx_set_misc
        redis2_query set $key $val;
        redis2_pass foo.com:6379;
    }

    location /bar {
        # $ is not special here...
        redis2_literal_raw_query '*1\r\n$4\r\nping\r\n';
        redis2_pass 127.0.0.1:6379;
    }

    location /bar {
        # variables can be used below and $ is special
        redis2_raw_query 'get one\r\n';
        redis2_pass 127.0.0.1:6379;
    }

    # GET /baz?get%20foo%0d%0a
    location /baz {
        set_unescape_uri $query $query_string; # this requires the ngx_set_misc module
        redis2_raw_query $query;
        redis2_pass 127.0.0.1:6379;
    }

Description
    This is an nginx upstream module that makes nginx talk to a redis 2.x
    server in a non-blocking way. The full Redis 2.0 unified protocol has
    been implemented except for the pipelining support which is still a
    TODO item.

    This module returns the raw TCP response from the redis server.
    It's recommended to use my lua-redis-parser module (written in
    pure C) to parse these responses into lua data structure when combined
    with the ngx_lua module:

       https://github.com/agentzh/lua-redis-parser

    If you only want to use the "get" redis command, you can try out the
    ngx_redis module here:

       http://wiki.nginx.org/HttpRedis

    It returns the parsed content part of the redis response because only
    "get" is needed to implement.

    Another option is to parse the redis responses on your client side yourself.

Directives
    redis2_query
        Multiple instances of this directive are allowd in
        a single location. These queries will be pipelined.
        But for now, only the first command's response will
        be returned.

    redis2_raw_query

    redis2_literal_raw_query

    redis2_pass

    redis2_connect_timeout
        syntax: *redis2_connect_timeout <time>*

        default: *60s*

        context: *http, server, location*

        The timeout for connecting to the redis server, in seconds by
        default.

        It's wise to always explicitly specify the time unit to avoid confusion.
        Time units supported are "s"(seconds), "ms"(milliseconds), "y"(years),
        "M"(months), "w"(weeks), "d"(days), "h"(hours), and "m"(minutes).

        This time must be less than 597 hours.

    redis2_send_timeout
        syntax: *redis2_send_timeout <time>*

        default: *60s*

        context: *http, server, location*

        The timeout for sending TCP requests to the redis server, in seconds
        by default.

        It's wise to always explicitly specify the time unit to avoid confusion.
        Time units supported are "s"(seconds), "ms"(milliseconds), "y"(years),
        "M"(months), "w"(weeks), "d"(days), "h"(hours), and "m"(minutes).

        This time must be less than 597 hours.

    redis2_read_timeout
        syntax: *redis2_read_timeout <time>*

        default: *60s*

        context: *http, server, location*

        The timeout for reading TCP responses from the redis server, in
        seconds by default.

        It's wise to always explicitly specify the time unit to avoid confusion.
        Time units supported are "s"(seconds), "ms"(milliseconds), "y"(years),
        "M"(months), "w"(weeks), "d"(days), "h"(hours), and "m"(minutes).

        This time must be less than 597 hours.

    redis2_buffer_size

    redis2_next_upstream

Connection Pool
    You can use Maxim Dounin's excellent ngx_http_upstream_keepalive module
    ( http://mdounin.ru/hg/ngx_http_upstream_keepalive/ )
    with this module to privide TCP connection pool
    for Redis.

    A sample config snippet looks like this

      http {
        upstream backend {
          server 127.0.0.1:6379;

          # a pool with at most 1024 connections
          # and do not distinguish the servers:
          keepalive 1024 single;
        }

        server {
            ...
            location /redis {
                set_unescape_uri $query $arg_query;
                redis2_query $query;
                redis2_pass backend;
            }
        }
      }

Lua Interoperability
    This module can be served as a non-blocking redis2 client
    for ngx_lua ( http://github.com/chaoslawful/lua-nginx-module ).

    Here's an example using a GET subrequest:

        location /redis {
            internal;

            # set_unescape_uri is provided by ngx_set_misc
            set_unescape_uri $query $arg_query;

            redis2_raw_query $query;
            redis2_pass 127.0.0.1:6379;
        }

        location /main {
            content_by_lua '
                local res = ngx.location.capture("/redis",
                    { args = { query = "ping\\r\\n" } }
                )
                ngx.print("[" .. res.body .. "]")
            ';
        }

    Then accessing /main yields

        [+PONG\r\n]

    where "\r\n" is CRLF. That is, this module returns the *raw* TCP responses
    from the remote redis server. For lua-based application developers, they
    may want to utilize the lua-redis-parser module (written in pure C) to
    parse such raw responses into Lua data structures:

        https://github.com/agentzh/lua-redis-parser

    When moving the inlined Lua code into an external .lua file, it's important
    to use the escape sequence "\r\n" directly. We used "\\r\\n" above just because
    the Lua code itself needs quoting when being put into an nginx string literal.

    You can also use POST/PUT subrequests to transfer the raw redis
    request via request body, which does not require URI escaping
    and unescaping, thus saving some CPU cycles. Here's such an example:

        location /redis {
            internal;

            # $echo_request_body is provided by the ngx_echo module
            redis2_raw_query $echo_request_body;

            redis2_pass 127.0.0.1:6379;
        }

        location /main {
            content_by_lua '
                local res = ngx.location.capture("/redis",
                    { method = ngx.HTTP_PUT,
                      body = "ping\\r\\n" }
                )
                ngx.print("[" .. res.body .. "]")
            ';
        }

    This yeilds exactly the same output as the previous (GET) sample.

    One can also use Lua to pick up a concrete Redis backend
    based on some complicated hashing rules. For
    instance,

        upstream redis-a {
            server foo.bar.com:6379;
        }

        upstream redis-b {
            server bar.baz.com:6379;
        }

        upstream redis-c {
            server blah.blah.org:6379;
        }

        server {
            ...

            location /redis {
                set_unescape_uri $query $arg_query;
                redis2_query $query;
                redis2_pass $arg_backend;
            }

            location /foo {
                content_by_lua "
                    -- pick up a server randomly
                    local servers = {'redis-a', 'redis-b', 'redis-c'}
                    local i = ngx.time() % #servers + 1;
                    local srv = servers[i]

                    local res = ngx.location.capture('/redis',
                        { args = {
                            query = '...',
                            backend = srv
                          } }
                    )
                    ngx.say(res.body)
                ";
            }
        }

Installation
    1. Grab the nginx source code from nginx.net (<http://nginx.net/>), for
        example, the version 0.8.54 (see nginx compatibility),

    2. and then build the source with this module:

        $ wget 'http://sysoev.ru/nginx/nginx-0.8.54.tar.gz'
        $ tar -xzvf nginx-0.8.54.tar.gz
        $ cd nginx-0.8.54/

        # Here we assume you would install you nginx under /opt/nginx/.
        $ ./configure --prefix=/opt/nginx \
            --add-module=/path/to/redis2-nginx-module

        $ make -j2
        $ make install

    Download the latest version of the release tarball of this module from
    redis2-nginx-module file list
    (<http://github.com/agentzh/redis2-nginx-module/downloads>).

Compatibility
    Redis 2.0, 2.2, and above should work with this module
    without any issues. So is the "Alchemy Database"
    (aka redisql).

    The following versions of Nginx should work with this module:

    *   0.9.x (last tested: 0.9.4)
    *   0.8.x >= 0.8.31 (last tested: 0.8.54)

    Earlier versions of Nginx will *not* work.

    If you find that any particular version of Nginx above 0.8.31 does not
    work with this module, please consider reporting a bug.

Report Bugs
    Although a lot of effort has been put into testing and code tuning,
    there must be some serious bugs lurking somewhere in this module. So
    whenever you are bitten by any quirks, please don't hesitate to

    1.  send a bug report or even patches to <agentzh@gmail.com>,

    2.  or create a ticket on the issue tracking interface
        (<http://github.com/agentzh/redis2-nginx-module/issues>)
        provided by GitHub.

Source Repository
    Available on github at agentzh/redis2-nginx-module
    (<http://github.com/agentzh/redis2-nginx-module>).

TODO
    * Add the "redis2_as_json" directive to allow emitting JSON directly.
    * Add full support for redis pipelining in the response parser.

AUTHORS
    Yichun "agentzh" Zhang (章亦春) < agentzh@gmail.com >

Getting involved
    You'll be very welcomed to submit patches to the author or just ask for
    a commit bit to the source repository on GitHub.

Copyright & License
    Copyright (c) 2010, 2011 Taobao Inc., Alibaba Group ( http://www.taobao.com
    ).

    Copyright (c) 2010, 2011 Yichun "agentzh" Zhang (章亦春) <agentzh@gmail.com>.

    This module is licensed under the terms of the BSD license.

    Redistribution and use in source and binary forms, with or without
    modification, are permitted provided that the following conditions are
    met:

    *   Redistributions of source code must retain the above copyright
        notice, this list of conditions and the following disclaimer.

    *   Redistributions in binary form must reproduce the above copyright
        notice, this list of conditions and the following disclaimer in the
        documentation and/or other materials provided with the distribution.

    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
    IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
    TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
    PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
    HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
    SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
    TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
    PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
    LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
    NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
    SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

SEE ALSO
    * a redis response parser for Lua: https://github.com/agentzh/lua-redis-parser