lua-resty-ssdb
Lua ssdb client driver for the ngx_lua based on the cosocket API
$ opm get risent/lua-resty-ssdb
RISENT changed
refactor code struct to table wrap
add all available command support from ssdb.io
convert response to lua mathing type
add test use Test::Nginx
IMWR changed
添加快捷连接鉴权 cache.connect(cache,host,port,auth);
local ok, err = cache.connect(cache, host, port, auth)
if not ok then
-- connect error string, eg: "timeout"、"bad port number"、"invalid password" ...
-- ngx.say(err)
end
Meger moonbingbing/master 优化 _read_reply() 返回
local result = cache:get(key)
if result == ngx.null then
-- do something
end
ngx.say(result)
Name
lua-resty-ssdb - Lua ssdb client driver for the ngx_lua based on the cosocket API
Status
This library is considedb production ready.
Description
This Lua library is a SSDB 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 0.5.14 or ngx_openresty 1.2.1.14 is required.
SSDB is an open source, advanced key-value store server based on leveldb database:
https://github.com/ideawu/ssdb
Synopsis
lua_package_path "/path/to/lua-resty-ssdb/lib/?.lua;;";
server {
location /test {
content_by_lua '
local ssdb = require "resty.ssdb"
local db = ssdb:new()
db:set_timeout(1000) -- 1 sec
local ok, err = db:connect("127.0.0.1", 8888)
if not ok then
ngx.say("failed to connect: ", err)
return
end
ok, err = db:set("dog", "an animal")
if not ok then
ngx.say("failed to set dog: ", err)
return
end
ngx.say("set result: ", ok)
local res, err = db:get("dog")
if not res then
ngx.say("failed to get dog: ", err)
return
end
if res == ngx.null then
ngx.say("dog not found.")
return
end
ngx.say("dog: ", res)
db:init_pipeline()
db:set("cat", "Marry")
db:set("horse", "Bob")
db:get("cat")
db:get("horse")
local results, err = db:commit_pipeline()
if not results then
ngx.say("failed to commit the pipelined requests: ", err)
return
end
for i, res in ipairs(results) do
if type(res) == "table" then
if not res[1] then
ngx.say("failed to run command ", i, ": ", res[2])
else
-- process the table value
end
else
-- process the scalar value
end
end
-- put it into the connection pool of size 100,
-- with 0 idle timeout
local ok, err = db:set_keepalive(0, 100)
if not ok then
ngx.say("failed to set keepalive: ", err)
return
end
-- or just close the connection right away:
-- local ok, err = db:close()
-- if not ok then
-- ngx.say("failed to close: ", err)
-- return
-- end
';
}
}
Methods
All of the SSDB commands have their own methods with the same name except all in lower case.
You can find the complete list of SSDB commands here:
https://github.com/ideawu/ssdb/wiki/Commands
You need to check out this SSDB command reference to see what SSDB command accepts what arguments.
The SSDB command arguments can be directly fed into the corresponding method call. For example, the "GET" SSDB command accepts a single key argument, then you can just call the "get" method like this:
local res, err = db:get("key")
Or, the "set" method with two arguments like this:
local res, err = db:set("key", "value")
And, the "SCAN" ssdb command accepts three arguments, then you should call the "scan" method like this:
local res, err = db:scan("0", "z", "8")
For example, "SET", "GET", "SCAN", and "RSCAN" commands correspond to the methods "set", "get", "scan", and "rscan".
All ssdb command methods returns a Lua table and nil
otherwise. In case of errors or failures, it will also return a second value which is a string describing the error.
If ssdb command only results in "status reply"(such as ok
, not found
, etc), then returns a Lua table only include status, otherwise SSDB returns a Lua table holding all the composing values (not include status).
A nil reply results in a ngx.null
return value.
See https://github.com/ideawu/ssdb/wiki/Commands for details regarding various SSDB reply types.
In addition to all those ssdb command methods, the following methods are also provided:
new
syntax: db, err = ssdb:new()
Creates a ssdb object. In case of failures, returns nil
and a string describing the error.
connect
syntax: ok, err = db:connect(host, port, options_table?)
Attempts to connect to the remote host and port that the ssdb server is listening to.
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.
An optional Lua table can be specified as the last argument to this method to specify various connect options:
pool
: Specifies a custom name for the connection pool being used. If omitted, then the connection pool name will be generated from the string template<host>:<port>
.
connect with auth
local ok, err = cache.connect(cache,host,port,auth);
Creates a ssdb object with auth. In case of failures, returns nil
and a string describing the error.
set_timeout
syntax: db:set_timeout(time)
Sets the timeout (in ms) protection for subsequent operations, including the connect
method.
set_keepalive
syntax: ok, err = db:set_keepalive(max_idle_timeout, pool_size)
Puts the current SSDB connection immediately 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.
Only call this method in the place you would have called the close
method instead. Calling this method will immediately turn the current ssdb object into the closed
state. Any subsequent operations other than connect()
on the current objet will return the closed
error.
get_reused_times
syntax: times, err = db: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 = db:close()
Closes the current ssdb connection and returns the status.
In case of success, returns 1
. In case of errors, returns nil
with a string describing the error.
init_pipeline
syntax: db:init_pipeline()
Enable the ssdb pipelining mode. All subsequent calls to SSDB command methods will automatically get cached and will send to the server in one run when the commit_pipeline
method is called or get cancelled by calling the cancel_pipeline
method.
This method always succeeds.
If the ssdb object is already in the SSDB pipelining mode, then calling this method will discard existing cached SSDB queries.
commit_pipeline
syntax: results, err = db:commit_pipeline()
Quits the pipelining mode by committing all the cached SSDB queries to the remote server in a single run. All the replies for these queries will be collected automatically and are returned as if a big multi-bulk reply at the highest level.
This method returns nil
and a Lua string describing the error upon failures.
cancel_pipeline
syntax: db:cancel_pipeline()
Quits the pipelining mode by discarding all existing cached SSDB commands since the last call to the init_pipeline
method.
This method always succeeds.
If the ssdb object is not in the SSDB pipelining mode, then this method is a no-op.
add_commands
syntax: hash = ssdb.add_commands(cmd_name1, cmd_name2, ...)
Adds new ssdb commands to the resty.ssdb
class. Here is an example:
local ssdb = require "resty.ssdb"
ssdb.add_commands("foo", "bar")
local db = ssdb:new()
db:set_timeout(1000) -- 1 sec
local ok, err = db:connect("127.0.0.1", 8888)
if not ok then
ngx.say("failed to connect: ", err)
return
end
local res, err = db:foo("a")
if not res then
ngx.say("failed to foo: ", err)
end
res, err = db:bar()
if not res then
ngx.say("failed to bar: ", err)
end
Debugging
It is usually convenient to use the lua-cjson library to encode the return values of the ssdb command methods to JSON. For example,
local cjson = require "cjson"
...
local res, err = db:multi_get("h1234", "h5678")
if res then
print("res: ", cjson.encode(res))
end
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.ssdb
object instance cannot be stodb in a Lua variable at the Lua module level, because it will then be shadb 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 sameresty.ssdb
instance. You should always initiateresty.ssdb
objects in function local variables or in thengx.ctx
table. These places all have their own data copies for each request.
Installation
If you are using the ngx_openresty bundle (http://openresty.org ), then you need to copy ssdb.lua
to resty dir because it does't includes lua-resty-ssdb by default. And you can just use it in your Lua code, as in
local ssdb = require "resty.ssdb"
...
If you're using your own nginx + ngx_lua build, then you need to configure the lua_package_path directive to add the path of your lua-resty-ssdb source tree to ngx_lua's LUA_PATH search path, as in
# nginx.conf
http {
lua_package_path "/path/to/lua-resty-ssdb/lib/?.lua;;";
...
}
TODO
Community
English Mailing List
The openresty-en mailing list is for English speakers.
Chinese Mailing List
The openresty mailing list is for Chinese speakers.
Bugs and Patches
Please report bugs or submit patches by
creating a ticket on the GitHub Issue Tracker,
or posting to the OpenResty community.
Author
Risent Zhang <shengqi542@gmail.com>
LazyZhu (lazyzhu.com) <billfzhu@gmail.com>
Yichun "agentzh" Zhang (章亦春) <agentzh@gmail.com>, CloudFlare Inc.
Copyright and License
This module is licensed under the BSD license.
Copyright (C) 2012-2013, by Yichun Zhang (agentzh) <agentzh@gmail.com>, CloudFlare Inc.
All rights reserved.
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
the ngx_lua module: http://wiki.nginx.org/HttpLuaModule
the ssdb widb protocol specification: https://github.com/ideawu/ssdb/wiki/Commands
the lua-resty-redis library
Authors
Risent Zhang (risent)
License
2bsd
Versions
-
Lua ssdb client driver for the ngx_lua based on the cosocket API 2017-08-21 14:35:54
-
Lua ssdb client driver for the ngx_lua based on the cosocket API 2017-08-16 15:29:18