[Lua]SkyWalking-nginx-lua0.3.0 traceid repeat all the time

[gudandezhu]

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• Question or discussion
• Bug
• Requirement
• Feature or performance improvement

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Bug

skywalking-nginx-lua0.3.0 , macOS , JRE8.0

when I used skywalking-nginx-lua0.3.0 , I got the same traceid(all api) ，I just changed the Nginx.conf
next is my nginx.conf :

this is log:

[wu-sheng]

@moonming @dmsolr We need to recheck this, once this is true, we need a 0.3.1 directly.

[Miss-you]

/accept

[wu-sheng]

Seem @membphis 's local test doesn't show the same issue.

[membphis]

we need to set the random seed in init_worker_by_lua_block phase:

--- a/README.md
+++ b/README.md
@@ -32,6 +32,7 @@ http {
         -- Instance means the number of Nginx deployment, does not mean the worker instances
         metadata_buffer:set('serviceInstanceName', 'User Service Instance Name')

+        require("skywalking.util").set_randomseed()
         require("skywalking.client"):startBackendTimer("http://127.0.0.1:8080")
     }

I will submit a new PR about this.

[Miss-you]

I think it's better to use ngx.var.request_id rather than generate uuid by itself.

[wu-sheng]

I like @Miss-you 's idea.

[Miss-you]

The distributed unique id generation algorithm is a classic problem, so we'll just use ngx.var.request_id here.

[wu-sheng]

I have removed high-priority as this UUID should be safe(maybe?). @Miss-you feel free to submit a PR to implement in your way, and we could include it in the 0.4.0.

[membphis]

@gudandezhu please confirm if you enabled the directive lua_code_cache in your Nginx config.

I can get the same output when using lua_code_cache off in Nginx config.

1. please remove lua_code_cache or set lua_code_cache on.
2. add require("skywalking.util").set_randomseed() in init_worker_by_lua_block, here is example: https://github.com/apache/skywalking-nginx-lua/pull/52/files#diff-b335630551682c19a781afebcf4d07bf978fb1f8ac04c6bf87428ed5106870f5R36

[gudandezhu]

yes , remove lua_code_cache is right