Clarify error message when unauthorized Kibana connection (#3753) (#3764

)

agentcfg/fetch.go

@@ -37,9 +37,9 @@ import (
 
 // Error Messages used to signal fetching errors
 const (
-	ErrMsgSendToKibanaFailed = "sending request to kibana failed"
-	ErrMsgReadKibanaResponse = "unable to read Kibana response body"
-
+	ErrMsgSendToKibanaFailed   = "sending request to kibana failed"
+	ErrMsgReadKibanaResponse   = "unable to read Kibana response body"
+	ErrUnauthorized            = "Unauthorized"
 	TransactionSamplingRateKey = "transaction_sample_rate"
 )
 

beater/api/config/agent/handler.go

@@ -187,6 +187,13 @@ func extractInternalError(c *request.Context, err error, withAuth bool) {
 		body = authErrMsg(msg, agentcfg.ErrMsgReadKibanaResponse, withAuth)
 		keyword = agentcfg.ErrMsgReadKibanaResponse
 
+	case strings.Contains(msg, agentcfg.ErrUnauthorized):
+		fullMsg := "APM Server is not authorized to query Kibana. " +
+			"Please configure apm-server.kibana.username and apm-server.kibana.password, " +
+			"and ensure the user has the necessary privileges."
+		body = authErrMsg(fullMsg, agentcfg.ErrUnauthorized, withAuth)
+		keyword = agentcfg.ErrUnauthorized
+
 	default:
 		body = authErrMsg(msg, msgServiceUnavailable, withAuth)
 		keyword = msgServiceUnavailable

beater/api/config/agent/handler_test.go

@@ -160,6 +160,18 @@ var (
 			respBody:               map[string]string{"error": msgMethodUnsupported},
 			respBodyToken:          map[string]string{"error": fmt.Sprintf("%s: PUT", msgMethodUnsupported)},
 		},
+
+		"Unauthorized": {
+			kbClient:               tests.MockKibana(http.StatusUnauthorized, m{"error": "Unauthorized"}, mockVersion, true),
+			method:                 http.MethodGet,
+			queryParams:            map[string]string{"service.name": "opbeans-node"},
+			respStatus:             http.StatusServiceUnavailable,
+			respCacheControlHeader: "max-age=300, must-revalidate",
+			respBody:               map[string]string{"error": agentcfg.ErrUnauthorized},
+			respBodyToken: map[string]string{"error": "APM Server is not authorized to query Kibana. " +
+				"Please configure apm-server.kibana.username and apm-server.kibana.password, " +
+				"and ensure the user has the necessary privileges."},
+		},
 	}
 )