Manage Nginx upstreams in pure Lua.
Probably production ready in most cases, though not yet proven in the wild. Please check the issues list and let me know if you have any problems / questions.
- Periodically heartbeat to upstream servers
- Passive health check
- Dynamic upstream update
- Balance by weighted round-robin or hash
- Sync with Nginx C upstream
- Try clusters by levels or by keys
-- config.lua
_M = {}
_M.global = {
checkup_timer_interval = 15,
checkup_shd_sync_enable = true,
shd_config_timer_interval = 1,
}
_M.ups1 = {
cluster = {
{
servers = {
{host="127.0.0.1", port=4444, weight=10, max_fails=3, fail_timeout=10},
}
},
},
}
lua_package_path "/path/to/lua-resty-checkups/lib/checkups/?.lua;/path/to/config.lua;;";
lua_shared_dict state 10m;
lua_shared_dict mutex 1m;
lua_shared_dict locks 1m;
lua_shared_dict config 10m;
server {
listen 12350;
return 200 12350;
}
server {
listen 12351;
return 200 12351;
}
init_worker_by_lua_block {
local config = require "config"
local checkups = require "resty.checkups.api"
checkups.prepare_checker(config)
checkups.create_checker()
}
server {
location = /12350 {
proxy_pass http://127.0.0.1:12350/;
}
location = /12351 {
proxy_pass http://127.0.0.1:12351/;
}
location = /t {
content_by_lua_block {
local checkups = require "resty.checkups.api"
local callback = function(host, port)
local res = ngx.location.capture("/" .. port)
ngx.say(res.body)
return 1
end
local ok, err
-- connect to a dead server, no upstream available
ok, err = checkups.ready_ok("ups1", callback)
if err then ngx.say(err) end
-- add server to ups1
ok, err = checkups.update_upstream("ups1", {
{
servers = {
{host="127.0.0.1", port=12350, weight=10, max_fails=3, fail_timeout=10},
}
},
})
if err then ngx.say(err) end
ngx.sleep(1)
ok, err = checkups.ready_ok("ups1", callback)
if err then ngx.say(err) end
ok, err = checkups.ready_ok("ups1", callback)
if err then ngx.say(err) end
-- add server to new upstream
ok, err = checkups.update_upstream("ups2", {
{
servers = {
{host="127.0.0.1", port=12351},
}
},
})
if err then ngx.say(err) end
ngx.sleep(1)
ok, err = checkups.ready_ok("ups2", callback)
if err then ngx.say(err) end
-- add server to ups2, reset rr state
ok, err = checkups.update_upstream("ups2", {
{
servers = {
{host="127.0.0.1", port=12350, weight=10, max_fails=3, fail_timeout=10},
{host="127.0.0.1", port=12351, weight=10, max_fails=3, fail_timeout=10},
}
},
})
if err then ngx.say(err) end
ngx.sleep(1)
ok, err = checkups.ready_ok("ups2", callback)
if err then ngx.say(err) end
ok, err = checkups.ready_ok("ups2", callback)
if err then ngx.say(err) end
}
}
A typical output of the /t location defined above is:
no upstream available
12350
12350
12351
12350
12351
Configuration file of checkups is a lua module consists of two parts, the global part and the cluster part.
An example configuration file of checkups is shown below,
_M = {}
-- Here is the global part
_M.global = {
checkup_timer_interval = 15,
checkup_timer_overtime = 60,
default_heartbeat_enable = true,
checkup_shd_sync_enable = true,
shd_config_timer_interval = 1,
}
-- The rests parts are cluster configurations
_M.redis = {
enable = true,
typ = "redis",
timeout = 2,
read_timeout = 15,
send_timeout = 15,
protected = true,
cluster = {
{ -- level 1
try = 2,
servers = {
{ host = "192.168.0.1", port = 6379, weight=10, max_fails=3, fail_timeout=10 },
{ host = "192.168.0.2", port = 6379, weight=10, max_fails=3, fail_timeout=10 },
}
},
{ -- level 2
servers = {
{ host = "192.168.0.3", port = 6379, weight=10, max_fails=3, fail_timeout=10 },
}
},
},
}
_M.api = {
enable = false,
typ = "http",
http_opts = {
query = "GET /status HTTP/1.1\r\nHost: localhost\r\n\r\n",
statuses = {
[500] = false,
[502] = false,
[503] = false,
[504] = false,
},
},
mode = "hash",
cluster = {
dc1 = {
servers = {
{ host = "192.168.1.1", port = 1234, weight=10, max_fails=3, fail_timeout=10 },
}
},
dc2 = {
servers = {
{ host = "192.168.1.2", port = 1234, weight=10, max_fails=3, fail_timeout=10 },
}
}
}
}
_M.ups_from_nginx = {
timeout = 2,
cluster = {
{ -- level 1
upstream = "api.com",
},
{ -- level 2
upstream = "api.com",
upstream_only_backup = true,
},
},
}
return _M
global configurations
checkup_timer_interval: Interval of sending heartbeats to backend servers. Default is5.checkup_timer_overtime: Interval of checkups to expire the timer key. In most cases, you don't need to change this value. Default is60.default_heartbeat_enable: Checkups will sent heartbeats to servers by default or not. Default istrue.checkup_shd_sync_enable: Create upstream syncer for each worker. If set tofalse, dynamic upstream will not work properly. Default istrue.shd_config_timer_interval: Interval of syncing upstream list from shared memory. Default is equal tocheckup_timer_interval.ups_status_sync_enable: If set totrue, checkups will sync upstram status from checkups to Nginx C upstream module. Default isfalse.ups_status_timer_interval: Interval of syncing upstream status from checkups to Nginx C upstream module.
Cluster configurations
-
enable: Enable or disable heartbeats to servers. Default istrue. -
typ: Cluster type, must be one ofgeneral,redis,mysql,http. Default isgeneral.general: Heartbeat by TCPsock:connect.redis: Heartbeat by redisPING. lua-resty-redis module is required.mysql: Heartbeat by mysqldb:connect. lua-resty-mysql module is required.http: Heartbeat by HTTP request. You can setup customized HTTP request and response codes inhttp_opts.
-
timeout: Connect timeout to upstream servers. Default is5. -
read_timeout: Read timeout to upstream servers. Default is equal totimeout. -
send_timeout: Write timeout to upstream servers. Default is equal totimeout. -
http_opts: HTTP heartbeat configurations. Only works fortyp="http".query: HTTP request to heartbeat.statuses: If the code returned by server is set tofalse, then the server is considered to be failing.
-
mode: Balance mode. If set tohash, checkups will balance servers byhash_keyorngx.req.uriif nohash_keyis specified. Default iswrr. -
protected: If set totrueand all the servers in the cluster are failing, checkups will not mark the last failing server as unavailable(err), instead, it will be marked asunstable(still available in next try). Default istrue. -
cluster: You can configure multiple levels according to the cluster priority, at each level you can configure a cluster ofservers. Checkups will try next level only when all the servers in the prior level are consitered unavailable.Instead of trying clusters by level, you can configure checkups trying clusters by key(see
apicluster above). Remember you should also pass extra argument likeopts.cluster_key={default="dc1", backup="dc2"}to checkups.read_ok to make checkups trying on the order ofdc1,dc2. If you haven't passedopts.cluster_keyto checkups.ready_ok, checkups will still try clusters by level. As for the aboveapicluster, checkups will eventually returnno upstream available. -
try: Retry count. Default is the number of servers. -
servers: Configuration forserversare listed as follows,weight: Sets the weight of the server. Default is1.max_fails: Sets the number of unsuccessful attempts to communicate with the server that should happen in the duration set by thefail_timeoutparameter. By default, the number of unsuccessful attempts is set to0, which disables the accounting of attempts. What is considered an unsuccessful attempt is defined byhttp_opts.statusesiftyp="http"or anil/falsereturn by checkups.ready_ok.fail_timeout: Sets the time during which the specified number of unsuccessful attempts to communicate with the server should happen to consider the server unavailable and the period of time the server will be considered unavailable. By default, the parameter is set to10seconds.
-
upstream: Name of Nginx C upstream. Checkups will extract servers from Nginx C upstream module in prepare_checker. lua-upstream-nginx-module module is required. -
upstream_only_backup: If set totrue, checkups will only extract backup servers from Nginx C upstream module.
Add pathes of lua config file and checkups to lua_package_path and create lua shared dicts used by checkups. You should put these lines into http block of your Nginx config file.
lua_package_path "/path/to/lua-resty-checkups/lib/checkups/?.lua;/path/to/config.lua;;";
lua_shared_dict state 10m;
lua_shared_dict mutex 1m;
lua_shared_dict locks 1m;
lua_shared_dict config 10m;
syntax: prepare_checker(config)
Copy configurations from config to checkups, extract servers from Nginx C upstream module and do some basic initialization. This method can be called in init phase or init_worker phase. If you want to extract servers from Nginx C upstream module, then you must call this method in init_worker phase.
syntax: create_checker()
Create heartbeat timer and upstream sync timer. Only one heartbeat timer will be created among all the workers. It's highly recommended to call this method in init_worker phase.
syntax: res, err = ready_ok(skey, callback, opts?)
Select an available peer from cluster skey and call callback(peer.host, peer.port, opts).
The opts table accepts the following fields,
cluster_key: Try clusters by key. Checkups will try clusters on the order ofcluster_key.default,cluster_key.backup.hash_key: Key used inhashbalance mode. If not set,ngx.req.uriwill be used.
Returns what callback returns on success, or returns nil and a string describing the error otherwise.
If callback returns nil or false, checkups will consider it to be a failed try and will retry callback with another peer. So, always remember not to return nil or false after a successful callback.
syntax: peer, err = select_peer(skey)
Select an available peer from cluster skey.
Return a table containing host and port of an available peer.
In case of errors, returns nil with a string describing the error.
syntax: status = get_status()
Return checkups status in json format.
syntax: connect_timeout, send_timeout, read_timeout = get_ups_timeout(skey)
Return timeout of cluster skey.
syntax: ok, err = feedback_status(skey, host, port, failed)
Mark server host:port in cluster skey as failed(true) or available(false).
Returns 1 on success, or returns nil and a string describing the error otherwise.
syntax: ok, err = update_upstream(skey, upstream)
Update cluster skey. upstream is in the same format as cluster in config.lua.
Returns true on success, or returns false and a string describing the error otherwise.
syntax: ok, err = delete_upstream(skey)
Delete cluster skey from upstream list.
Returns true on success, or returns false and a string describing the error otherwise.
The bundle itself is licensed under the 2-clause BSD license.
Copyright (c) 2016, UPYUN(又拍云) Inc.
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.
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