Fix merging Kubernetes configuration

[mszostok]

Description

Changes proposed in this pull request:

• I tried to add some linter to warns when assigning the address of the variable from range, but unfortunately, none were able to catch this because we are passing that pointer to a function. Even revive.

It's a valid candidate for cherry-picking into v1.4.1 release.

Testing

Unit tests

Writing manual compare was too slow, so first I used

dump = litter.Options{
	StripPackageNames:         true,
	HidePrivateFields:         false,
	HideZeroValues:            true,
	DisablePointerReplacement: true,
	Separator:                 " ",
}
dump.Sdump(router.table)

but this was not producing readable enough assets, so I decided to go with YAML, but for that I had to export fields. Because the struct is still private, it doesn't change anything.

Manual

1. Create cluster: k3d cluster create
2. Build k8s plugin: PLUGIN_TARGETS="kubernetes" make build-plugins-single
3. Start server: env PLUGIN_SERVER_HOST=http://host.k3d.internal go run test/helpers/plugin_server.go
4. Create Botkube config:

   communications:
     default-group:
       socketSlack:
         enabled: true
         channels:
           default:
             name: hakuna-matata
             bindings:
               sources:
                 - "k8s-all-events"
               executors: [ ]
         appToken: "xapp-"
         botToken: "xoxb-"
   
   sources:
     "k8s-all-events":
       botkube/kubernetes:
         enabled: true
         config:
           namespaces:
             include:
               - ".*"
           event:
             types:
               - delete
               - error
           resources:
             - type: v1/services
             - type: networking.k8s.io/v1/ingresses
             - type: v1/nodes
             - type: v1/namespaces
             - type: v1/persistentvolumes
             - type: v1/persistentvolumeclaims
             - type: v1/configmaps
               namespaces:
                 include:
                   - ".*"
                 exclude:
                   - "gitlab-runner"
             - type: rbac.authorization.k8s.io/v1/roles
             - type: rbac.authorization.k8s.io/v1/rolebindings
             - type: rbac.authorization.k8s.io/v1/clusterrolebindings
             - type: rbac.authorization.k8s.io/v1/clusterroles
             - type: apps/v1/daemonsets
             - type: batch/v1/jobs
             - type: apps/v1/deployments
             - type: apps/v1/statefulsets
   
   plugins:
     cacheDir: "/tmp/plugins"
   
     repositories:
       botkube:
         url: http://host.k3d.internal:3010/botkube.yaml
   
   
   settings:
     log:
       level: "debug"
       formatter: "text"
     clusterName: "labs"
     upgradeNotifier: false
   
   analytics:
     disable: true
   
   configWatcher:
     enabled: false
   

5. Start Botkube: env BOTKUBE_CONFIG_PATHS="./helm/botkube/values.yaml,/tmp/debug-events.yaml" go run ./cmd/botkube-agent/main.go
6. Create configmap in gitlab-runner ns and delete it, create configmap in default ns and try to delete it.

   kc create ns gitlab-runner
   
   kubectl create configmap my-config --from-literal=key1=config1 -n gitlab-runner                                                                                                                       
   kubectl create configmap my-config --from-literal=key1=config1 -n default
   
   kubectl delete cm my-config -n gitlab-runner
   kubectl delete cm my-config -n default

Related issue(s)

#1251

[josefkarasek]

Good find, I bet it took some time. Well done 👍

[josefkarasek]

🤯