Fix appending a port to metrics server address if it is empty

commands/config.go

@@ -82,10 +82,10 @@ func (c *configOptionsWithMetricsServer) metricsServerAddress() (string, error)
 
 	_, port, err := net.SplitHostPort(address)
 	if err != nil && !strings.Contains(err.Error(), "missing port in address") {
-		return address, err
+		return "", err
 	}
 
-	if len(port) == 0 {
+	if len(address) > 0 && len(port) == 0 {
 		return fmt.Sprintf("%s:%d", address, common.DefaultMetricsServerPort), nil
 	}
 	return address, nil

commands/config_test.go

@@ -8,6 +8,55 @@ import (
 	"gitlab.com/gitlab-org/gitlab-ci-multi-runner/common"
 )
 
+func TestMetricsServerNone(t *testing.T) {
+	cfg := configOptionsWithMetricsServer{}
+	cfg.config = &common.Config{}
+
+	address, err := cfg.metricsServerAddress()
+	assert.NoError(t, err)
+	assert.Equal(t, address, "")
+}
+
+func TestMetricsServerEmpty(t *testing.T) {
+	cfg := configOptionsWithMetricsServer{}
+	cfg.config = &common.Config{}
+	cfg.MetricsServerAddress = ""
+
+	address, err := cfg.metricsServerAddress()
+	assert.NoError(t, err)
+	assert.Equal(t, address, "")
+}
+
+func TestMetricsServerEmptyCommonConfig(t *testing.T) {
+	cfg := configOptionsWithMetricsServer{}
+	cfg.config = &common.Config{}
+	cfg.config.MetricsServerAddress = ""
+
+	address, err := cfg.metricsServerAddress()
+	assert.NoError(t, err)
+	assert.Equal(t, address, "")
+}
+
+func TestMetricsServerInvalid(t *testing.T) {
+	cfg := configOptionsWithMetricsServer{}
+	cfg.config = &common.Config{}
+	cfg.MetricsServerAddress = "localhost::1234"
+
+	address, err := cfg.metricsServerAddress()
+	assert.Error(t, err)
+	assert.Equal(t, address, "")
+}
+
+func TestMetricsServerInvalidCommonConfig(t *testing.T) {
+	cfg := configOptionsWithMetricsServer{}
+	cfg.config = &common.Config{}
+	cfg.config.MetricsServerAddress = "localhost::1234"
+
+	address, err := cfg.metricsServerAddress()
+	assert.Error(t, err)
+	assert.Equal(t, address, "")
+}
+
 func TestMetricsServerDefaultPort(t *testing.T) {
 	cfg := configOptionsWithMetricsServer{}
 	cfg.config = &common.Config{}
@@ -15,7 +64,7 @@ func TestMetricsServerDefaultPort(t *testing.T) {
 
 	address, err := cfg.metricsServerAddress()
 	assert.NoError(t, err)
-	assert.Equal(t, address, fmt.Sprintf("%s:%d", cfg.MetricsServerAddress, common.DefaultMetricsServerPort))
+	assert.Equal(t, fmt.Sprintf("%s:%d", cfg.MetricsServerAddress, common.DefaultMetricsServerPort), address)
 }
 
 func TestMetricsServerDefaultPortCommonConfig(t *testing.T) {