reuse filewatcher

[zirain]

1. reuse filewatcher package
2. move code under util

[codecov]

Codecov Report

Attention: Patch coverage is 59.49367% with 32 lines in your changes missing coverage. Please review.

Project coverage is 66.21%. Comparing base (8adbf1d) to head (203f50b).
Report is 63 commits behind head on main.

Files with missing lines	Patch %	Lines
internal/provider/file/file.go	0.00%	26 Missing ⚠️
internal/filewatcher/worker.go	85.71%	2 Missing and 1 partial ⚠️
internal/utils/path/path.go	86.95%	2 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #4475      +/-   ##
==========================================
+ Coverage   65.74%   66.21%   +0.46%     
==========================================
  Files         210      208       -2     
  Lines       31516    31329     -187     
==========================================
+ Hits        20721    20743      +22     
+ Misses       9598     9390     -208     
+ Partials     1197     1196       -1     

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[zirain]

cc @shawnh2 PTAL

[shawnh2]

Done some test, seems running envoy-gateway server -c config.yaml with config.yaml:

apiVersion: gateway.envoyproxy.io/v1alpha1
kind: EnvoyGateway
gateway:
  controllerName: gateway.envoyproxy.io/gatewayclass-controller
provider:
  type: Custom
  custom:
    resource:
      type: File
      file:
        paths: ["test/"]
logging:
  level:
    default: info

cannot catch any modifications (like vim, echo etc) under the paths.

[zirain]

@shawnh2 can you review and test this again?