OpenResty
需求：
OpenResty運行在Docker中岂座，后端代理的server存在IP不固定的情況，需要OpenResty動態(tài)更新后端地址
實現(xiàn)思路：
- 在OpenResty中定義共享Dict洞斯，將后端IP保存在其中
- 設(shè)置/add和/delete的location，通過Web調(diào)用增刪后端IP
- 設(shè)置proxy_pass代理坑赡，代理的地址從共享Dict中獲取實現(xiàn)請求
過程驗證(這里所有服務(wù)在一個Centos 7 Docker中啟動)：
- 啟動兩個后端服務(wù)
- 啟動三個終端烙如，在第一個終端中啟動web服務(wù)test1
[root@f2d9f997edac /]# mkdir -p test1 && cd test1 && echo test1 > test
[root@f2d9f997edac test1]# python -m SimpleHTTPServer 8081
Serving HTTP on 0.0.0.0 port 8081 ...
- 在第二個終端中啟動web服務(wù)test2
[root@f2d9f997edac /]# mkdir -p test2 && cd test2 && echo test2 > test
[root@f2d9f997edac test2]# python -m SimpleHTTPServer 8082
Serving HTTP on 0.0.0.0 port 8082 ...
- 在第三個終端中驗證test1和test2
[root@f2d9f997edac /]# curl 127.0.0.1:8081/test
test1
[root@f2d9f997edac /]# curl 127.0.0.1:8082/test
test2
- 安裝OpenResty并配置
- 在第三個終端中，執(zhí)行下面命令安裝Openresty（此處為CentOS系統(tǒng)毅否，其余系統(tǒng)的安裝命令請自行搜索）
[root@f2d9f997edac /]# yum install -y openresty
- 編輯配置文件亚铁，驗證配置文件并啟動Openrestry
[root@f2d9f997edac /]# cat /usr/local/openresty/nginx/conf/nginx.conf
worker_processes 4;
events {
worker_connections 1024;
}
http {
include mime.types;
default_type application/octet-stream;
log_format main '$remote_addr - $remote_user [$time_local] "$request" '
'$status $body_bytes_sent "$http_referer" '
'"$http_user_agent" "$http_x_forwarded_for"';
#access_log logs/access.log main;
sendfile on;
#tcp_nopush on;
keepalive_timeout 65;
#gzip on;
lua_shared_dict ups 10m;
server {
listen 80;
location /add {
content_by_lua_block {
local ups = ngx.shared.ups
local ip = ngx.req.get_uri_args()["ip"]
local port = ngx.req.get_uri_args()["port"]
local no = ngx.req.get_uri_args()["no"]
if ip == nil or port == nil or no == nil then
ngx.say("usage: /add?ip=x.x.x.x&port=xx&no=xx")
return
end
ups:set("host-"..no, ip)
ups:set("port-"..no, port)
-- ups["host-"..no] = ip
-- ups["port-"..no] = port
local count = 0
for k in pairs(ups:get_keys(0)) do count = count + 1 end
ups:set("servers", count)
ngx.say("OK")
}
}
location /get {
content_by_lua_block {
local ups = ngx.shared.ups
local no = ngx.req.get_uri_args()["no"]
if no == nil then
ngx.say("usage: /get?no=xx")
return
end
if ups:get("host-" .. no) == nil then
ngx.say("the no server is vaild: " .. no)
return
end
local count = 0
for k in pairs(ups:get_keys(0)) do count = count + 1 end
ups:set("servers", count)
ngx.say("ip: " .. ups:get("host-" .. no))
ngx.say("port: " .. ups:get("port-" .. no))
ngx.say("servers: " .. math.floor(ups:get("servers")/2))
}
}
location /delete {
content_by_lua_block {
local ups = ngx.shared.ups
local no = ngx.req.get_uri_args()["no"]
if no == nil then
ngx.say("usage: /get?no=xx")
return
end
if ups:get("host-" .. no) == nil then
ngx.say("the no server is vaild: " .. no)
return
end
ups:delete("host-" .. no)
ups:delete("port-" .. no)
ngx.say("OK")
}
}
location / {
set_by_lua_block $cur_ups {
local ups = ngx.shared.ups
local items = ups:get("servers")
local n = math.random(math.floor(items/2))
local ss = string.gsub(ups:get_keys(0)[n], "%a+-", "")
s = ups:get("host-"..ss) .. ":" .. ups:get("port-"..ss)
return s
}
proxy_next_upstream off;
proxy_set_header Host $host;
proxy_http_version 1.1;
proxy_set_header Connection "";
proxy_pass $scheme://$cur_ups;
}
}
}
[root@f2d9f997edac /]# openresty -t
nginx: the configuration file /usr/local/openresty/nginx/conf/nginx.conf syntax is ok
nginx: configuration file /usr/local/openresty/nginx/conf/nginx.conf test is successful
[root@f2d9f997edac /]# openresty
- 增加后端服務(wù)并驗證（/get通過no查詢后端服務(wù)的IP和端口）
- 在add的時候指定后端服務(wù)的no(序列號)、IP和端口信息
- no用來區(qū)分不同后端服務(wù)螟加，執(zhí)行相同no的提交會覆蓋原來的no信息
- proxy_pass拿到的后端服務(wù)隨機產(chǎn)生(2中的math.random(math.floor(items/2))處)
[root@f2d9f997edac /]# curl '127.0.0.1:80/add?no=1&ip=127.0.0.1&port=8081'
OK
[root@f2d9f997edac /]# curl '127.0.0.1:80/get?no=1'
ip: 127.0.0.1
port: 8081
servers: 1
[root@f2d9f997edac /]# curl '127.0.0.1:80/add?no=2&ip=127.0.0.1&port=8082'
OK
[root@f2d9f997edac /]# curl '127.0.0.1:80/get?no=2'
ip: 127.0.0.1
port: 8082
servers: 2
[root@f2d9f997edac /]# curl '127.0.0.1:80/test'
test1
[root@f2d9f997edac /]# curl '127.0.0.1:80/test'
test2
[root@f2d9f997edac /]#
- 刪除后端服務(wù)并驗證
/delete通過no刪除后端服務(wù)的IP和端口信息
[root@f2d9f997edac /]# curl '127.0.0.1:80/delete?no=1'
OK
[root@f2d9f997edac /]# curl '127.0.0.1:80/get?no=1'
the no server is vaild: 1
[root@f2d9f997edac /]# curl '127.0.0.1:80/get?no=2'
ip: 127.0.0.1
port: 8082
servers: 1
[root@f2d9f997edac /]# curl '127.0.0.1:80/test'
test2
[root@f2d9f997edac /]# curl '127.0.0.1:80/test'
test2
[root@f2d9f997edac /]#
存在不足：
- 如果由程序控制OpenResty的/add和/delete來維護后端服務(wù)信息徘溢，需要保證與序號no的對應
- proxy_pass中的后端服務(wù)地址和端口對通過隨機拿到吞琐，存在負載不均衡的情況，可以根據(jù)自己的實際需求修改然爆，比如修改為ip_hash站粟，但需要考慮保存在共享內(nèi)存Dict中后端服務(wù)的數(shù)量
