fix(controller): add backward compatibility for --metricsport flag. Fixes #4428

Add deprecated --metricsport flag alias to maintain backward compatibility
with Helm charts while encouraging migration to --metricsPort.

- Adds --metricsport as deprecated alias for --metricsPort
- Shows deprecation warning when --metricsport is used
- Maintains full backward compatibility with existing deployments

Signed-off-by: puretension <rlrlfhtm5@gmail.com>

Author: puretension

cmd/rollouts-controller/main.go

@@ -303,6 +303,8 @@ func newCommand() *cobra.Command {
 	command.Flags().StringVar(&logFormat, "logformat", "", "Set the logging format. One of: text|json")
 	command.Flags().IntVar(&klogLevel, "kloglevel", 0, "Set the klog logging level")
 	command.Flags().IntVar(&metricsPort, "metricsPort", controller.DefaultMetricsPort, "Set the port the metrics endpoint should be exposed over")
+	command.Flags().IntVar(&metricsPort, "metricsport", controller.DefaultMetricsPort, "Set the port the metrics endpoint should be exposed over (deprecated, use --metricsPort)")
+	command.Flags().MarkDeprecated("metricsport", "use --metricsPort instead")
 	command.Flags().IntVar(&healthzPort, "healthzPort", controller.DefaultHealthzPort, "Set the port the healthz endpoint should be exposed over")
 	command.Flags().StringVar(&instanceID, "instance-id", "", "Indicates which argo rollout objects the controller should operate on")
 	command.Flags().Float32Var(&qps, "qps", defaults.DefaultQPS, "Maximum QPS (queries per second) to the K8s API server")

cmd/rollouts-controller/main_test.go

@@ -0,0 +1,21 @@
+package main
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestMetricsPortFlagCompatibility(t *testing.T) {
+	cmd := newCommand()
+
+	// Test that both flags are available
+	metricsPortFlag := cmd.Flags().Lookup("metricsPort")
+	assert.NotNil(t, metricsPortFlag, "metricsPort flag should exist")
+
+	metricsportFlag := cmd.Flags().Lookup("metricsport")
+	assert.NotNil(t, metricsportFlag, "metricsport flag should exist for backward compatibility")
+
+	// Test that deprecated flag is marked as deprecated
+	assert.True(t, metricsportFlag.Deprecated != "", "metricsport flag should be marked as deprecated")
+}