Fix hetzner and openstack tests by adding AWS_EC2_METADATA_DISABLED=t…

…rue in ec2 (#37907) (#38016)

(cherry picked from commit 38e7d6f)

Co-authored-by: kaiyan-sheng <kaiyan.sheng@elastic.co>

libbeat/processors/add_cloud_metadata/provider_aws_ec2_test.go

@@ -35,6 +35,14 @@ import (
 	"github.com/elastic/elastic-agent-libs/mapstr"
 )
 
+func init() {
+	// Disable IMDS when the real AWS SDK IMDS client is used,
+	// so tests are isolated from the environment. Otherwise,
+	// tests for non-EC2 providers may fail when the tests are
+	// run within an EC2 VM.
+	os.Setenv("AWS_EC2_METADATA_DISABLED", "true")
+}
+
 type MockIMDSClient struct {
 	GetInstanceIdentityDocumentFunc func(ctx context.Context, params *imds.GetInstanceIdentityDocumentInput, optFns ...func(*imds.Options)) (*imds.GetInstanceIdentityDocumentOutput, error)
 }

libbeat/processors/add_cloud_metadata/provider_hetzner_cloud_test.go

@@ -31,7 +31,7 @@ import (
 )
 
 func hetznerMetadataHandler() http.HandlerFunc {
-	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+	return func(w http.ResponseWriter, r *http.Request) {
 		if r.RequestURI == hetznerMetadataInstanceIDURI {
 			_, _ = w.Write([]byte("111111"))
 			return
@@ -50,7 +50,7 @@ func hetznerMetadataHandler() http.HandlerFunc {
 		}
 
 		http.Error(w, "not found", http.StatusNotFound)
-	})
+	}
 }
 
 func TestRetrieveHetznerMetadata(t *testing.T) {

libbeat/processors/add_cloud_metadata/provider_openstack_nova_test.go

@@ -31,26 +31,26 @@ import (
 )
 
 func openstackNovaMetadataHandler() http.HandlerFunc {
-	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+	return func(w http.ResponseWriter, r *http.Request) {
 		if r.RequestURI == osMetadataInstanceIDURI {
-			w.Write([]byte("i-0000ffac"))
+			_, _ = w.Write([]byte("i-0000ffac"))
 			return
 		}
 		if r.RequestURI == osMetadataInstanceTypeURI {
-			w.Write([]byte("m1.xlarge"))
+			_, _ = w.Write([]byte("m1.xlarge"))
 			return
 		}
 		if r.RequestURI == osMetadataHostnameURI {
-			w.Write([]byte("testvm01.stack.cloud"))
+			_, _ = w.Write([]byte("testvm01.stack.cloud"))
 			return
 		}
 		if r.RequestURI == osMetadataZoneURI {
-			w.Write([]byte("az-test-2"))
+			_, _ = w.Write([]byte("az-test-2"))
 			return
 		}
 
 		http.Error(w, "not found", http.StatusNotFound)
-	})
+	}
 }
 
 func TestRetrieveOpenstackNovaMetadata(t *testing.T) {

libbeat/processors/add_cloud_metadata/provider_tencent_cloud_test.go

@@ -33,15 +33,15 @@ import (
 func initQCloudTestServer() *httptest.Server {
 	return httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		if r.RequestURI == "/meta-data/instance-id" {
-			w.Write([]byte("ins-qcloudv5"))
+			_, _ = w.Write([]byte("ins-qcloudv5"))
 			return
 		}
 		if r.RequestURI == "/meta-data/placement/region" {
-			w.Write([]byte("china-south-gz"))
+			_, _ = w.Write([]byte("china-south-gz"))
 			return
 		}
 		if r.RequestURI == "/meta-data/placement/zone" {
-			w.Write([]byte("gz-azone2"))
+			_, _ = w.Write([]byte("gz-azone2"))
 			return
 		}