feat: support merging user and default bootstrap configurations

[zhaohuabing]

Related issue: #1685

Since this is a breaking change, please consider including the following notification, or something similar, in the release note to remind the users to update their EnvoyProxy configuration.

Important The Booststrap field of EnvoyProxy API has been changed from a string to a struct. Please ensure you adjust your EnvoyProxy configurations accordingly. Here is an example:

Before:

apiVersion: config.gateway.envoyproxy.io/v1alpha1
kind: EnvoyProxy
metadata:
  name: custom-proxy-config
  namespace: envoy-gateway-system
spec:
  bootstrap: |
    admin:
      access_log: // truncated for brevity

After:

apiVersion: config.gateway.envoyproxy.io/v1alpha1
kind: EnvoyProxy
metadata:
  name: custom-proxy-config
  namespace: envoy-gateway-system
spec:
  bootstrap:
    type: Replace
    value: |
      admin:
        access_log: // truncated for brevity

[codecov]

Codecov Report

Merging #1791 (46a9e04) into main (23652af) will decrease coverage by 0.08%.
The diff coverage is 59.74%.

@@            Coverage Diff             @@
##             main    #1791      +/-   ##
==========================================
- Coverage   65.15%   65.07%   -0.08%     
==========================================
  Files          84       86       +2     
  Lines       12230    12281      +51     
==========================================
+ Hits         7968     7992      +24     
- Misses       3754     3775      +21     
- Partials      508      514       +6     

Files Changed	Coverage Δ
internal/xds/bootstrap/util.go	0.00% <0.00%> (ø)
api/config/v1alpha1/validation/validate.go	74.73% <53.84%> (-2.19%)	⬇️
...ternal/infrastructure/kubernetes/proxy/resource.go	91.39% <62.50%> (-1.66%)	⬇️
internal/cmd/egctl/translate.go	83.07% <63.63%> (-0.36%)	⬇️
internal/utils/yaml/yaml.go	75.00% <75.00%> (ø)

[arkodg]

thanks for picking this up @zhaohuabing, can you split up API and implementation into 2 PRs, which may help with faster reviews, thanks !

[zhaohuabing]

thanks for picking this up @zhaohuabing, can you split up API and implementation into 2 PRs, which may help with faster reviews, thanks !

@arkodg Since this is a breaking change, it won't pass the build if just changing the API.

[arkodg]

thanks for picking this up @zhaohuabing, can you split up API and implementation into 2 PRs, which may help with faster reviews, thanks !

@arkodg Since this is a breaking change, it won't pass the build if just changing the API.

ah yah, sure lets stick with this for now

[zhaohuabing]

@arkodg Should I add a notice in the release note so that users won't be surprised by this breaking change? If yes, do you know where to add this note?

[arkodg]

@arkodg Should I add a notice in the release note so that users won't be surprised by this breaking change? If yes, do you know where to add this note?

added the release note label, hopefully this reminds the release manager to add this note, we can work on proactively adding release notes too, maybe in the PR description that the release manager can copy into the release notes

[arkodg]

can we use https://github.com/evanphx/json-patch instead, i.e. convert the YAMLs into JSON using sigs.k8s.io/yaml and then use jsonpatch.MergePatch and convert it back to YAML ?

[zhaohuabing]

jsonpatch.MergePatch can't merge two JSON strings, and there are no other methods to merge JSON strings either.

See https://github.com/evanphx/json-patch#create-and-apply-a-merge-patch

[arkodg]

can we also update the user docs https://gateway.envoyproxy.io/latest/user/customize-envoyproxy.html#customize-envoyproxy-bootstrap-config in this PR or as a follow up, thanks !

[zirain]

LGTM, thanks @zhaohuabing !

[arkodg]

LGTM thanks !