Support managed identity auth in azuremonitor receiver

receiver/azuremonitorreceiver/config.go

@@ -249,6 +249,7 @@ type Config struct {
 const (
 	servicePrincipal = "service_principal"
 	workloadIdentity = "workload_identity"
+	managedIdentity  = "managed_identity"
 )
 
 // Validate validates the configuration by checking for missing or invalid fields
@@ -282,8 +283,13 @@ func (c Config) Validate() (err error) {
 		if c.FederatedTokenFile == "" {
 			err = multierr.Append(err, errMissingFedTokenFile)
 		}
+
+	case managedIdentity:
+		if c.ClientID == "" {
+			err = multierr.Append(err, errMissingClientID)
+		}
 	default:
-		return fmt.Errorf("authentication %v is not supported. supported authentications include [%v,%v]", c.Authentication, servicePrincipal, workloadIdentity)
+		return fmt.Errorf("authentication %v is not supported. supported authentications include [%v,%v,%v]", c.Authentication, servicePrincipal, workloadIdentity, managedIdentity)
 	}
 
 	if c.Cloud != azureCloud && c.Cloud != azureGovernmentCloud {

receiver/azuremonitorreceiver/scraper.go

@@ -106,6 +106,7 @@ type azureScraper struct {
 	mb                              *metadata.MetricsBuilder
 	azIDCredentialsFunc             func(string, string, string, *azidentity.ClientSecretCredentialOptions) (*azidentity.ClientSecretCredential, error)
 	azIDWorkloadFunc                func(options *azidentity.WorkloadIdentityCredentialOptions) (*azidentity.WorkloadIdentityCredential, error)
+	azIDManagedIdentityFunc         func(options *azidentity.ManagedIdentityCredentialOptions) (*azidentity.ManagedIdentityCredential, error)
 	armClientOptions                *arm.ClientOptions
 	armClientFunc                   func(string, azcore.TokenCredential, *arm.ClientOptions) (*armresources.Client, error)
 	armMonitorDefinitionsClientFunc func(string, azcore.TokenCredential, *arm.ClientOptions) (*armmonitor.MetricDefinitionsClient, error)
@@ -184,6 +185,12 @@ func (s *azureScraper) loadCredentials() (err error) {
 		if s.cred, err = s.azIDWorkloadFunc(nil); err != nil {
 			return err
 		}
+	case managedIdentity:
+		if s.cred, err = s.azIDManagedIdentityFunc(&azidentity.ManagedIdentityCredentialOptions{
+			ID: azidentity.ClientID(s.cfg.ClientID),
+		}); err != nil {
+			return err
+		}
 	default:
 		return fmt.Errorf("unknown authentication %v", s.cfg.Authentication)
 	}