Awesome

Name

lua-resty-beanstalkd - Lua beanstalkd client driver for the ngx_lua based on the cosocket API

Based on the lua-resty-memcached library.

Influenced by beanstalk-client-ruby

Status

This library is currently very unstable. It is being written primarily for the author's education of ngx_lua cosockets.

Only the "put" and "delete" commands are supported. Only the default beanstalkd tube may be used.

Description

This Lua library is a beanstalkd client driver for the ngx_lua nginx module:

http://wiki.nginx.org/HttpLuaModule

This Lua library takes advantage of ngx_lua's cosocket API, which ensures 100% nonblocking behavior.

Note that at least ngx_lua 0.5.0rc29 or ngx_openresty 1.0.15.7 is required.

Synopsis

lua_package_path "/path/to/lua-resty-beanstalkd/lib/?.lua;;";

server {
    location /test {
        content_by_lua '
            local beanstalkd = require "resty.beanstalkd"
            local b = beanstalkd.new()
            local ok, err = b:connect()
            if not ok then
                ngx.say("failed to connect: ", err)
                return
            end
            local ok, id, err = b:put("foo")
            ngx.say(ok)
            ok, err = b:delete(id)
            ngx.say(ok)
            b:close()
        ';
    }
}

Methods

new

syntax: b, err = beanstalkd:new()

Creates a beanstalkd object. In case of failures, returns nil and a string describing the error.

connect

syntax: ok, err = b:connect(host, port)

Attempts to connect to the remote host and port that the beanstalkd server is listening to or a local unix domain socket file listened by the beanstalkd server.

Before actually resolving the host name and connecting to the remote backend, this method will always look up the connection pool for matched idle connections created by previous calls of this method.

Host defaults to 127.0.0.1 and port defaults to 11300.

put

syntax: ok, id, err = b:put(body, pri, delay, ttr)

Inserts a job into the queue.

body should be a string.

pri is the priority and defaults to 65536

delay defaults to 0

ttr -- time to run -- defaults to 0

In case of success, returns true and the job id. On error, it will return false, nil, and an error message.

delete

syntax: ok, id, err = b:delete(id)

Deletes a job from the queue.

In case of success, returns true. On error, it will return false and an error message.

set_timeout

syntax: b:set_timeout(time)

Sets the timeout (in ms) protection for subsequent operations, including the connect method.

set_keepalive

syntax: ok, err = b:set_keepalive(max_idle_timeout, pool_size)

Keeps the current beanstalkd connection alive and put it into the ngx_lua cosocket connection pool.

You can specify the max idle timeout (in ms) when the connection is in the pool and the maximal size of the pool every nginx worker process.

In case of success, returns 1. In case of errors, returns nil with a string describing the error.

get_reused_times

syntax: times, err = b:get_reused_times()

This method returns the (successfully) reused times for the current connection. In case of error, it returns nil and a string describing the error.

If the current connection does not come from the built-in connection pool, then this method always returns 0, that is, the connection has never been reused (yet). If the connection comes from the connection pool, then the return value is always non-zero. So this method can also be used to determine if the current connection comes from the pool.

close

syntax: ok, err = memc:close()

Closes the current beanstalkd connection and returns the status.

In case of success, returns 1. In case of errors, returns nil with a string describing the error.

Limitations

This library cannot be used in code contexts like set_by_lua*, log_by_lua*, and header_filter_by_lua* where the ngx_lua cosocket API is not available.
The resty.beanstalkd object instance cannot be stored in a Lua variable at the Lua module level, because it will then be shared by all the concurrent requests handled by the same nginx worker process (see http://wiki.nginx.org/HttpLuaModule#Data_Sharing_within_an_Nginx_Worker ) and result in bad race conditions when concurrent requests are trying to use the same resty.beanstalkd instance. You should always initiate resty.beanstalkd objects in function local variables or in the ngx.ctx table. These places all have their own data copies for each request.
Only the default tube is used.

TODO

Support the use command. We may not want to do a round trip each time, so could we use socket pools and only issue a use when get_reusedtimes returns 0?

Author

Brian Akins brian@akins.org

Copyright and License

This module is licensed under 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.