[chore] Move newNodeSharedInformer to a common/shared pkg (#32591)

**Description:** <Describe what has changed.>
<!--Ex. Fixing a bug - Describe the bug and how this fixes the issue.
Ex. Adding a feature - Explain what this achieves.-->
This PR implements some basic refactoring required for
#32295.
Doing this in a standalone PR was requested at
#32295 (comment).

The change moves a library method called `newNodeSharedInformer` from
the `k8sattributes` processor package to a generic one since it can be
re-used by multiple various components.

Note: I'm not sure if a changelog is required for this change, so I left
it out for now.

**Link to tracking Issue:** <Issue number if applicable>

**Testing:** <Describe what testing was performed and which tests were
added.>

**Documentation:** <Describe the documentation added.>

Signed-off-by: ChrsMark <chrismarkou92@gmail.com>
Co-authored-by: Tyler Helmuth <12352919+TylerHelmuth@users.noreply.github.com>

connector/datadogconnector/go.mod

@@ -83,6 +83,7 @@ require (
 	github.com/golang/protobuf v1.5.4 // indirect
 	github.com/golang/snappy v0.0.4 // indirect
 	github.com/google/gnostic-models v0.6.8 // indirect
+	github.com/google/go-cmp v0.6.0 // indirect
 	github.com/google/gofuzz v1.2.0 // indirect
 	github.com/google/pprof v0.0.0-20240227163752-401108e1b7e7 // indirect
 	github.com/google/uuid v1.6.0 // indirect

exporter/datadogexporter/integrationtest/go.mod

@@ -82,6 +82,7 @@ require (
 	github.com/golang/protobuf v1.5.4 // indirect
 	github.com/golang/snappy v0.0.4 // indirect
 	github.com/google/gnostic-models v0.6.8 // indirect
+	github.com/google/go-cmp v0.6.0 // indirect
 	github.com/google/gofuzz v1.2.0 // indirect
 	github.com/google/uuid v1.6.0 // indirect
 	github.com/grpc-ecosystem/grpc-gateway/v2 v2.19.1 // indirect

internal/k8sconfig/config.go

@@ -4,16 +4,24 @@
 package k8sconfig // import "github.com/open-telemetry/opentelemetry-collector-contrib/internal/k8sconfig"
 
 import (
+	"context"
 	"fmt"
 	"net"
 	"net/http"
 	"os"
+	"time"
 
 	quotaclientset "github.com/openshift/client-go/quota/clientset/versioned"
+	api_v1 "k8s.io/api/core/v1"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/apimachinery/pkg/fields"
+	"k8s.io/apimachinery/pkg/runtime"
 	k8sruntime "k8s.io/apimachinery/pkg/util/runtime"
+	"k8s.io/apimachinery/pkg/watch"
 	"k8s.io/client-go/dynamic"
 	k8s "k8s.io/client-go/kubernetes"
 	"k8s.io/client-go/rest"
+	"k8s.io/client-go/tools/cache"
 	"k8s.io/client-go/tools/clientcmd"
 )
 
@@ -179,3 +187,25 @@ func MakeOpenShiftQuotaClient(apiConf APIConfig) (quotaclientset.Interface, erro
 
 	return client, nil
 }
+
+func NewNodeSharedInformer(client k8s.Interface, nodeName string, watchSyncPeriod time.Duration) cache.SharedInformer {
+	informer := cache.NewSharedInformer(
+		&cache.ListWatch{
+			ListFunc: func(opts metav1.ListOptions) (runtime.Object, error) {
+				if nodeName != "" {
+					opts.FieldSelector = fields.OneTermEqualSelector("metadata.name", nodeName).String()
+				}
+				return client.CoreV1().Nodes().List(context.Background(), opts)
+			},
+			WatchFunc: func(opts metav1.ListOptions) (watch.Interface, error) {
+				if nodeName != "" {
+					opts.FieldSelector = fields.OneTermEqualSelector("metadata.name", nodeName).String()
+				}
+				return client.CoreV1().Nodes().Watch(context.Background(), opts)
+			},
+		},
+		&api_v1.Node{},
+		watchSyncPeriod,
+	)
+	return informer
+}

internal/k8sconfig/go.mod

@@ -4,6 +4,7 @@ go 1.21.0
 
 require (
 	github.com/openshift/client-go v0.0.0-20210521082421-73d9475a9142
+	k8s.io/api v0.29.3
 	k8s.io/apimachinery v0.29.3
 	k8s.io/client-go v0.29.3
 )
@@ -18,6 +19,7 @@ require (
 	github.com/gogo/protobuf v1.3.2 // indirect
 	github.com/golang/protobuf v1.5.4 // indirect
 	github.com/google/gnostic-models v0.6.8 // indirect
+	github.com/google/go-cmp v0.6.0 // indirect
 	github.com/google/gofuzz v1.2.0 // indirect
 	github.com/google/uuid v1.4.0 // indirect
 	github.com/imdario/mergo v0.3.11 // indirect
@@ -40,7 +42,6 @@ require (
 	gopkg.in/inf.v0 v0.9.1 // indirect
 	gopkg.in/yaml.v2 v2.4.0 // indirect
 	gopkg.in/yaml.v3 v3.0.1 // indirect
-	k8s.io/api v0.29.3 // indirect
 	k8s.io/klog/v2 v2.110.1 // indirect
 	k8s.io/kube-openapi v0.0.0-20231010175941-2dd684a91f00 // indirect
 	k8s.io/utils v0.0.0-20230726121419-3b25d923346b // indirect

internal/kubelet/go.mod

@@ -23,6 +23,7 @@ require (
 	github.com/gogo/protobuf v1.3.2 // indirect
 	github.com/golang/protobuf v1.5.4 // indirect
 	github.com/google/gnostic-models v0.6.8 // indirect
+	github.com/google/go-cmp v0.6.0 // indirect
 	github.com/google/gofuzz v1.2.0 // indirect
 	github.com/google/uuid v1.4.0 // indirect
 	github.com/imdario/mergo v0.3.11 // indirect

internal/metadataproviders/go.mod

@@ -38,6 +38,7 @@ require (
 	github.com/gogo/protobuf v1.3.2 // indirect
 	github.com/golang/protobuf v1.5.4 // indirect
 	github.com/google/gnostic-models v0.6.8 // indirect
+	github.com/google/go-cmp v0.6.0 // indirect
 	github.com/google/gofuzz v1.2.0 // indirect
 	github.com/google/uuid v1.6.0 // indirect
 	github.com/hashicorp/errwrap v1.1.0 // indirect

processor/k8sattributesprocessor/internal/kube/client.go

@@ -172,7 +172,7 @@ func New(logger *zap.Logger, apiCfg k8sconfig.APIConfig, rules ExtractionRules,
 	}
 
 	if c.extractNodeLabelsAnnotations() || c.extractNodeUID() {
-		c.nodeInformer = newNodeSharedInformer(c.kc, c.Filters.Node)
+		c.nodeInformer = k8sconfig.NewNodeSharedInformer(c.kc, c.Filters.Node, 5*time.Minute)
 	}
 
 	return c, err

processor/k8sattributesprocessor/internal/kube/informer.go

@@ -40,28 +40,6 @@ type InformerProviderNode func(
 	client kubernetes.Interface,
 ) cache.SharedInformer
 
-func newNodeSharedInformer(client kubernetes.Interface, nodeName string) cache.SharedInformer {
-	informer := cache.NewSharedInformer(
-		&cache.ListWatch{
-			ListFunc: func(opts metav1.ListOptions) (runtime.Object, error) {
-				if nodeName != "" {
-					opts.FieldSelector = fields.OneTermEqualSelector("metadata.name", nodeName).String()
-				}
-				return client.CoreV1().Nodes().List(context.Background(), opts)
-			},
-			WatchFunc: func(opts metav1.ListOptions) (watch.Interface, error) {
-				if nodeName != "" {
-					opts.FieldSelector = fields.OneTermEqualSelector("metadata.name", nodeName).String()
-				}
-				return client.CoreV1().Nodes().Watch(context.Background(), opts)
-			},
-		},
-		&api_v1.Node{},
-		watchSyncPeriod,
-	)
-	return informer
-}
-
 // InformerProviderReplicaSet defines a function type that returns a new SharedInformer. It is used to
 // allow passing custom shared informers to the watch client.
 type InformerProviderReplicaSet func(