Canary release using Apisix failed when using certain ApisixRoutePlugins

[zzr93]

Describe the bug

I run apisix canary release example smoothly, then I add "api-breaker" plugin to my ApisixRoute and trigger a canary release, it fails.

These logs are from flagger pod:

"Starting canary analysis for podinfo.test"
"Advance podinfo.test canary weight 10"
"Apisix route podinfo-podinfo-canary updated"
"Starting canary analysis for podinfo.test"
"apisix route podinfo.test update error: Operation cannot be fulfilled on apisixroutes.apisix.apache.org \"podinfo-podinfo-canary\": the object has been modified; please apply your changes to the latest version and try again"
"Apisix route podinfo-podinfo-canary updated"
"Starting canary analysis for podinfo.test"
"Advance podinfo.test canary weight 10"
"Apisix route podinfo-podinfo-canary updated"

from this we know that flagger updates podinfo-podinfo-canary every loop, and this behavior finally results into a canary failure.

Dive into the codes, we found this method in file pkg/apis/apisix/v2/types.go implements DeepCopy using json.

func (p ApisixRoutePluginConfig) DeepCopyInto(out *ApisixRoutePluginConfig) {
	b, _ := json.Marshal(&p)
	_ = json.Unmarshal(b, out)
}

Since json regards all numbers as float64, int values(such as 502 in api-breaker) get trouble during the diff calculating section in every loop.

diff := cmp.Diff(canaryApisixRoute.Spec, apisixRouteClone.Spec, cmpopts.IgnoreFields(a6v2.ApisixRouteHTTPBackend{}, "Weight"))

To Reproduce

1. Run podinfo example according to this doc:
2. Add plugin "api-breaker" into ApisixRoute as follows:

apiVersion: apisix.apache.org/v2
kind: ApisixRoute
metadata:
  name: podinfo
  namespace: test
spec:
  http:
    - backends:
        - serviceName: podinfo
          servicePort: 80
      match:
        hosts:
          - app.example.com
        methods:
          - GET
        paths:
          - /*
      name: method
      plugins:
        - name: api-breaker
          enable: true
          config:
            break_response_code: 502
            unhealthy:
              http_statuses: [500, 503]
              failure: 3
            healthy:
              http_statuses: [200]
              successes: 1
        - name: prometheus
          enable: true
          config:
            disable: false
            prefer_name: true

3. Trigger a canary release, and then the bug will show up.

Expected behavior

Canary release process successfully when using ApisixPlugins with integer values.

Additional context

• Flagger version: v1.29.0
• Kubernetes version: v1.20.15
• Service Mesh provider:
• Ingress provider: apisix