Skillfully use NGX_ Lua makes traffic grouping

background

• Test environment parallel testing ： A service has multiple requirements tested at the same time , need nginx Forward the traffic to the designated testing machine according to the specific information .

• Full link piezometry ： The flow is indistinguishable , Affect online users , The pressure test can only be carried out at the low peak of the business , Need to be on duty , The high cost , Need to be able to isolate traffic , Pressure measurement can be carried out at any time .

• Grayscale Publishing ： need nginx According to the specified information, the traffic is forwarded to the specified gray-scale machine .

ngx_lua modular

ngx_lua yes Nginx A module of , take Lua Embedded in Nginx in , So that you can use Lua To write a script , So you can use it Lua Write application scripts , Deploy to Nginx Run in , namely Nginx Become a Web Containers ; So developers can use Lua High performance in language development Web Applied .

ngx_lua Provided with Nginx A lot of interaction API, For developers, all they need to learn is API Then we can develop the function .

ngx_lua  Operation instruction

ngx_lua Belong to nginx Part of , Its execution instructions are contained in nginx Of 11 Step by step , The corresponding processing stage can do plug-in processing , Pluggable architecture , however ngx_lua Not all phases will run ; In addition, the instructions can be in http、server、server if、location、location if Configure several ranges ：

Set the flow label

Mode one ：

The requesting party will tag Add to header in , Directly request the original domain name

...
if (tag == "" or checkTag(host_pass, tag) == false)
 then
 return host_pass;
end
...

return host_pass.."_"..tag;

set_by_lua_file $host_pass set_tag.lua;


Mode two ：

The requesting party will tag Splice into the domain name ,nginx Upon receipt of the request , Split request host, And then tag Add to header And then forward it to the business nginx.

...
local host = ngx.var.host
local hostList = split(host, ".")
local subDomain = split(hostList[1], "-")
...
ngx.req.set_header("global-route-tag", subDomain[2])
ngx.header["global-route-tag"] = subDomain[2]
...
local test_host = ipList[1].."."..hostList[2].."."..hostList[3]
return test_host

set_by_lua_file $test_host set_test_servers.lua ;

location / {
 ...
 proxy_pass http://$host_pass;
 proxy_set_header Host $test_host;
 proxy_set_header X-Forwarded-For $remote_addr;
 proxy_set_header X-Real-IP $remote_addr; 
 proxy_set_header X-Forwarded-Proto $scheme;
}


Use method 1 to add tag To header Is not intuitive , Interface testing requires the help of other tools to add tag, Using mode 2 can reduce the operation complexity , It can also avoid the binding of office network access test environment host Failure to take effect . Therefore, we recommend the configuration method of mode 2 during internal testing .

combination dyups Online and offline tagging Services

In the last share , We shared nginx Smooth the process of online and offline services , Some students have noticed that we have supported the incremental update queue in the landing practice tag Service update for , When there is tag We will tag Splice to upstream in , You can continue to smooth the online and offline services .

Students can review

《 around WEB How can services achieve smoother changes 》

Realization effect

Post tagged groups , Group the same service , When the publishing platform deploys different groups , Put on different labels . Add the function of online traffic grouping , Solve pressure measurement 、 Grayscale publishing and other issues that require traffic grouping .

summary

about Nginx Adhesion Lua To develop applications can be said to be a sharp Swiss Army knife , It can help us solve many problems easily , Finally, we conclude based on Nginx+Lua Some common practices and scenarios in common architectural patterns ：

• WEB Application firewall （waf）;

• Current limiting ;

• Downgrade ;

• Service quality monitoring .

About author

Yun Zhou Zhao , Turn to operation and maintenance development , Responsible for operation and maintenance automation tools 、 Platform support . Love to think , Love operation and maintenance .

Turn to the technology learning and exchange platform of R & D center and industry partners , Regularly share front-line practical experience and cutting-edge technical topics in the industry .

Official account 「 Transfer technology 」（ Comprehensive ）、「 Big turn FE」（ Focus on FE）、「 around QA」（ Focus on QA）, More dry goods practices , Welcome to share ~