[receiver/k8sobjectsreceiver] k8sobject receiver support leader election

Signed-off-by: Murphy Chen <[email protected]>

Author: Frapschen

receiver/k8sobjectsreceiver/README.md

@@ -25,6 +25,7 @@ The following is example configuration
 ```yaml
   k8sobjects:
     auth_type: serviceAccount
+    k8s_leader_elector: k8s_leader_elector
     objects:
       - name: pods
         mode: pull
@@ -56,6 +57,7 @@ the K8s API server. This can be one of `none` (for no auth), `serviceAccount`
 use this config to specify the group to select. By default, it will select the first group.
 For example, `events` resource is available in both `v1` and `events.k8s.io/v1` APIGroup. In 
 this case, it will select `v1` by default.
+- `k8s_leader_elector` (default: none): if specified, will enable Leader Extension by using `k8sleaderelector` extension
 
 
 The full list of settings exposed for this receiver are documented in [config.go](./config.go)

receiver/k8sobjectsreceiver/config.go

@@ -9,6 +9,7 @@ import (
 	"strings"
 	"time"
 
+	"go.opentelemetry.io/collector/component"
 	"k8s.io/apimachinery/pkg/runtime/schema"
 	apiWatch "k8s.io/apimachinery/pkg/watch"
 	"k8s.io/client-go/discovery"
@@ -52,6 +53,8 @@ type Config struct {
 
 	Objects []*K8sObjectsConfig `mapstructure:"objects"`
 
+	K8sLeaderElector *component.ID `mapstructure:"k8s_leader_elector"`
+
 	// For mocking purposes only.
 	makeDiscoveryClient func() (discovery.ServerResourcesInterface, error)
 	makeDynamicClient   func() (dynamic.Interface, error)

receiver/k8sobjectsreceiver/go.mod

@@ -4,6 +4,7 @@ go 1.23.0
 
 require (
 	github.com/google/uuid v1.6.0
+	github.com/open-telemetry/opentelemetry-collector-contrib/extension/k8sleaderelector v0.122.0
 	github.com/open-telemetry/opentelemetry-collector-contrib/internal/k8sconfig v0.122.0
 	github.com/open-telemetry/opentelemetry-collector-contrib/pkg/golden v0.122.0
 	github.com/open-telemetry/opentelemetry-collector-contrib/pkg/pdatatest v0.122.0
@@ -130,7 +131,7 @@ require (
 	k8s.io/kube-openapi v0.0.0-20241105132330-32ad38e42d3f // indirect
 	k8s.io/utils v0.0.0-20241104100929-3ea5e8cea738 // indirect
 	sigs.k8s.io/json v0.0.0-20241010143419-9aa6b5e7a4b3 // indirect
-	sigs.k8s.io/structured-merge-diff/v4 v4.4.2 // indirect
+	sigs.k8s.io/structured-merge-diff/v4 v4.4.3 // indirect
 	sigs.k8s.io/yaml v1.4.0 // indirect
 )
 
@@ -152,3 +153,5 @@ replace github.com/open-telemetry/opentelemetry-collector-contrib/pkg/pdatatest
 replace github.com/open-telemetry/opentelemetry-collector-contrib/pkg/pdatautil => ../../pkg/pdatautil
 
 replace github.com/open-telemetry/opentelemetry-collector-contrib/pkg/golden => ../../pkg/golden
+
+replace github.com/open-telemetry/opentelemetry-collector-contrib/extension/k8sleaderelector => ../../extension/k8sleaderelector

receiver/k8sobjectsreceiver/go.sum

@@ -24,6 +24,7 @@ import (
 	"k8s.io/client-go/tools/cache"
 	"k8s.io/client-go/tools/watch"
 
+	"github.com/open-telemetry/opentelemetry-collector-contrib/extension/k8sleaderelector"
 	"github.com/open-telemetry/opentelemetry-collector-contrib/receiver/k8sobjectsreceiver/internal/metadata"
 )
 
@@ -66,17 +67,38 @@ func newReceiver(params receiver.Settings, config *Config, consumer consumer.Log
 	}, nil
 }
 
-func (kr *k8sobjectsreceiver) Start(ctx context.Context, _ component.Host) error {
+func (kr *k8sobjectsreceiver) Start(ctx context.Context, host component.Host) error {
 	client, err := kr.config.getDynamicClient()
 	if err != nil {
 		return err
 	}
 	kr.client = client
-	kr.setting.Logger.Info("Object Receiver started")
-
 	cctx, cancel := context.WithCancel(ctx)
 	kr.cancel = cancel
 
+	if kr.config.K8sLeaderElector != nil {
+		k8sLeaderElector := host.GetExtensions()[*kr.config.K8sLeaderElector]
+		if k8sLeaderElector == nil {
+			return fmt.Errorf("unknown k8s leader elector %q", kr.config.K8sLeaderElector)
+		}
+
+		kr.setting.Logger.Info("Trying to become the leader")
+		elector := k8sLeaderElector.(k8sleaderelector.LeaderElection)
+		elector.SetCallBackFuncs(
+			func(ctx context.Context) {
+				kr.setting.Logger.Info("Object Receiver started as leader")
+				for _, object := range kr.config.Objects {
+					kr.start(cctx, object)
+				}
+			},
+			func() {
+				kr.setting.Logger.Info("Object Receiver stopped as leader lose")
+				kr.Shutdown(context.Background())
+			})
+		return nil
+	}
+
+	kr.setting.Logger.Info("Object Receiver started")
 	for _, object := range kr.config.Objects {
 		kr.start(cctx, object)
 	}