log request_header when key set

[ning1875]

Description

When the log format is configured, it is also expected to print some important request headers such as the release that identifies the lane to help troubleshoot the request problem, so the user needs to configure the header list to be printed

Checklist

• I have explained the need for this PR and the problem it solves
• I have explained the changes or the new features added to this PR
• I have added tests corresponding to this change
• I have updated the documentation to reflect this change
• I have verified that this change is backward compatible (If not, please discuss on the APISIX mailing list first)

eg

• config like this

"request_header_keys": [
    "release",
    "env",
  ]

• log like

"release"="dev",
"env"="stage"

[juststillthinking]

Hi @ning1875, I don't think you need to create this pr to implement this function.
You could record the request header like this, we suppose the nginx and apisix variable

curl http://127.0.0.1:9180/apisix/admin/plugin_metadata/file-logger -H 'X-API-KEY: edd1c9f034335f136f87ad84b625c8f1' -X PUT -d '
{
  "log_format": {
    "release": "$http_release",
  }
}'

[ning1875]

Hi @ning1875, I don't think you need to create this pr to implement this function. You could record the request header like this, we suppose the nginx and apisix variable

curl http://127.0.0.1:9180/apisix/admin/plugin_metadata/file-logger -H 'X-API-KEY: edd1c9f034335f136f87ad84b625c8f1' -X PUT -d '
{
  "log_format": {
    "release": "$http_release",
  }
}'

test ok ,it works 。so does it support by openresty ?

[juststillthinking]

It's an nginx variable, and you could refer to this: https://github.com/openresty/lua-nginx-module#ngxvarvariable

[juststillthinking]

I will close this pr, feel free to reopen it