lua-resty-shdict-server - A HTTP and Redis protocol compatible interface for debugging ngx.shared API
This is a library that provides a HTTP and a Redis protocol compatible interface to debug ngx.shared.DICT API.
It can also be used as a mocking Redis server (WIP).
Production.
Shared dictionaries defined in http
and stream
subsystems are not shared to each other currently, thus we need two sets of configurations to debug with either subsystem.
However there're patches if you want to share shdict between http
and stream
subsystems. After apply the patch, you will need to use two lua_shared_dict
directives to define shared dict twice with same name and same size. e.g.:
http {
lua_shared_dict dogs 10m;
}
stream {
lua_shared_dict dogs 10m;
}
This module provide a similar API to use in both subsystems.
lua_shared_dict dogs 10m;
server {
listen 80;
location =/cli {
content_by_lua_block {
require "resty.core"
local srv = require("resty.shdict.server")
local s = srv:new("foobar", nil)
s:serve()
}
}
}
This sets up a simple HTTP server. Use any http client like curl
to issue a http request to the location we configured. For example:
$ curl "http://host/cli?dict=dogs&cmd=set%20dog%20wow&password=foobar"
OK
$ curl "http://host/cli?dict=dogs&cmd=get%20dog&password=foobar"
"wow"
lua_shared_dict dogs 10m;
server {
listen 127.0.0.1:18001;
content_by_lua_block {
require "resty.core.shdict"
require "resty.shdict.redis-commands"
local srv = require("resty.shdict.server")
local s = srv:new("foobar", nil)
s:serve()
}
}
This sets up a simple TCP server. Use telnet or equivalent tools to connect interactively. For example:
$ telnet 127.0.0.1 18001
Trying 127.0.0.1...
Connected to 127.0.0.1.
Escape character is '^]'.
SELECT dogs
-ERR authentication required
AUTH foobar
+OK
SELECT dogs
+OK
SET dog wow
+OK
GET dog
+wow
Also it supports Redis RESP protocol.
$ redis-cli -h 127.0.0.1 -p 18001
127.0.0.1:18001> get dogs
(error) ERR authentication required
127.0.0.1:18001> auth foobar
OK
127.0.0.1:18001> set dog wow
(error) ERR no shdict selected
127.0.0.1:18001> select dogs
OK
127.0.0.1:18001> set dog wow
OK
127.0.0.1:18001> get dog
wow
Initialize the server instance with password and pre-selected shared dictionary shdict.
If password is not set, the server is public. If password is set, client must call auth command to authenticate before running other commands. Please take proper security measurements if you're listening to non-local interfaces.
If shdict is not set, client must call select command to select a shared dictionary.
Start the server with handler named *mode. To run handler
serve_stream_redis`, use:
shdict.server:serve("stream_redis")
If mode is not defined, default handler for each subsystem is used. For http
the default handler is serve_http_plain
. For stream
the default handler is serve_stream_redis
.
This handler accept a single HTTP request from client and send the response back in plain text.
This handler accept a single HTTP request from client and send the response back in json encoded text.
This handler accept a single HTTP request from client and send the response formatted by output_filter
.
If output_filter
is not defined, output_plain is used and this handler is equivalent to serve_http_plain
.
output_filter
is a function that takes a table as argument and returns a string. User can define their own filter and genereate desirable output.
This handler accept TCP connection in inline or Redis protocol. A plain text TCP client like telnet
or nc
or a Redis-compatible client or library can be used to connect to the server.
Methods from ngx.shared.DICT
API are supported.
- ngx.shared.DICT
- ngx.shared.DICT.get
- ngx.shared.DICT.get_stale
- ngx.shared.DICT.set
- ngx.shared.DICT.safe_set
- ngx.shared.DICT.add
- ngx.shared.DICT.safe_add
- ngx.shared.DICT.replace
- ngx.shared.DICT.delete
- ngx.shared.DICT.incr
- ngx.shared.DICT.lpush
- ngx.shared.DICT.rpush
- ngx.shared.DICT.lpop
- ngx.shared.DICT.rpop
- ngx.shared.DICT.llen
- ngx.shared.DICT.ttl
- ngx.shared.DICT.expire
- ngx.shared.DICT.flush_all
- ngx.shared.DICT.flush_expired
- ngx.shared.DICT.get_keys
- ngx.shared.DICT.capacity
- ngx.shared.DICT.free_space
Some of the commands like ttl
and capacity
require the resty.core
being installed. To use these commands, put require('resty.core')
for http subsystem and require('resty.core.shdict')
for stream subsystem.
Methods names are case-insensitive. Arguments are seperated by spaces.
For example:
- To set a value wow with key dog, use
SET dog wow
orsEt dog wow
. - To set a value wow ! with key dog, use
SET dog "wow !"
. - To set a value "wow" ! with key dog, use
SET dog "\"wow\" !"
.
Some commands are mapped to redis-flavoured commands if resty.shdict.redis-commands
is included.
setnx
as an alias ofadd
setex
as an alias ofreplace
flushall
as an alias offlush_all
Authenticate to the server.
Returns OK if password is valid.
> AUTH password
Select a shared dictionary.
Returns OK if shdict is found.
> SELECT shdict
Test connection to the server.
Returns PONG.
> PING
This command requires the resty.shdict.redis-commands
module.
Return all keys matching pattern in a list. The pattern is a glob-style pattern.
The time complexity is O(3n). This command is for debug only, please do not use in production code to search for keys.
> KEYS pattern
> KEYS do?
> KEYS do*
> KEYS do[a-z]
This command requires the resty.shdict.redis-commands
module.
Run a Lua script on the server. The syntax is same as Redis EVAL.
> EVAL script numkeys key [key ...] arg [arg ...]
> EVAL "shdict.call('set', 'dog', 'wow') 0
(nil)
> EVAL "return {KEYS[1],KEYS[2],ARGV[1],ARGV[2]}" 2 key1 key2 first second
1) "key1"
2) "key2"
3) "first"
4) "second"
For security reasons, only the following APIs are available:
- Functions:
assert
,error
,getmetatable
,ipairs
,next
,pairs
,pcall
,select
,setmetatable
,tonumber
,tostring
,unpack
- Modules:
bit
,math
,string
,table
ngx.shared
andngx.re
shdict.call
andshdict.pcall
for invoking shdict APIszone
as the current shdict instance
Also an alias from redis.call
to shdict.call
is created for convenience.
This command requires the resty.shdict.redis-commands
module.
Get the user flag for a key.
Return nil
if the user flag is not set or key is not found.
GETFLAG key
This command requires the resty.shdict.redis-commands
module.
Delete one or more keys from shdict.
Returns OK.
DEL key [key ...]
DELETE key [key ...]
- The library will use
resty.core
if it's installed, the behaviour will be slightly different from the C implementation. For example, missing arguments will be filled bynil
when usingresty.core
, issuingSET a
is equivalent toSET a nil
in this situation. - For performance issues, inline protocol (HTTP inline or Redis inline) only accept four arguments at most.
EVAL
may fail with Invalid argument(s) for this reason. To solve this, always use other protocols (like Redis RESP protocol) to call these commands. EVAL
command is not atomic when running multipleshdict.call
altough the script is run on server.
- Add more ngx.* API to EVAL command.
- Add atomic SETFLAG command.
- Return affected keys count for DEL command.
- Add INFO command.
This module is licensed under the BSD license.
Copyright (C) 2018, by fffonion [email protected].
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.