openresty--基于redis实现一个动态路由

本文的一个例子主要介绍如何利用redis实现对请求头中User-Agent修改已达到路由到两个不同的http后台的目的。这个例子使用了这些openresty组件： Redis2 Nginx Module, Lua Nginx Module, Lua Redis Parser Library, 和 Set Misc Nginx Module。

1. 配置nginx

下面是完整的nginx.conf

worker_processes  1;
error_log logs/error.log info;

events {
worker_connections 1024;
}

http {
upstream apache.org {
server apache.org;
}

upstream nginx.org {
server nginx.org;
}

server {
listen 8080;

location = /redis {
internal;
set_unescape_uri $key $arg_key;
redis2_query get $key;
redis2_pass 127.0.0.1:6379;
}

location / {
set $target '';
access_by_lua '
local key = ngx.var.http_user_agent
local res = ngx.location.capture(
"/redis", { args = { key = key } }
)

print("key: ", key)

if res.status ~= 200 then
ngx.log(ngx.ERR, "redis server returned bad status: ",
res.status)
ngx.exit(res.status)
end

if not res.body then
ngx.log(ngx.ERR, "redis returned empty body")
ngx.exit(500)
end

local parser = require "redis.parser"
local server, typ = parser.parse_reply(res.body)
if typ ~= parser.BULK_REPLY or not server then
ngx.log(ngx.ERR, "bad redis response: ", res.body)
ngx.exit(500)
end

print("server: ", server)

ngx.var.target = server
';

proxy_pass http://$target; }
}
}

2. 启动redis

$ ./redis-server  # default port is 6379

在启动的redis中设置相关key：

$ ./redis-cli
redis> set foo apache.org
OK
redis> set bar nginx.org
OK

3. 测试nginx应用：

$ curl --user-agent foo localhost:8080
<apache.org home page goes here>

$ curl --user-agent bar localhost:8080
<nginx.org home page goes here>

如果想获取更好的性能，那么可以启用(redis链接池)[]http://openresty.org/cn/redis-2-nginx-module.html]。

ref: http://openresty.org/cn/dynamic-routing-based-on-redis.html