make it possible to access config server over a different network int…

…erface so we can make assertions with docker services
signalfx · Jan 10, 2025 · 96ed032 · 96ed032
1 parent 9badcfe
commit 96ed032
Show file tree

Hide file tree

Showing 2 changed files with 39 additions and 24 deletions.
diff --git a/internal/configconverter/config_server.go b/internal/configconverter/config_server.go
@@ -37,12 +37,13 @@ import (
 )
 
 const (
-	configServerEnabledEnvVar   = "SPLUNK_DEBUG_CONFIG_SERVER"
-	configServerPortEnvVar      = "SPLUNK_DEBUG_CONFIG_SERVER_PORT"
-	defaultConfigServerPort     = "55554"
-	defaultConfigServerEndpoint = "localhost:" + defaultConfigServerPort
-	effectivePath               = "/debug/configz/effective"
-	initialPath                 = "/debug/configz/initial"
+	configServerEnabledEnvVar           = "SPLUNK_DEBUG_CONFIG_SERVER"
+	configServerPortEnvVar              = "SPLUNK_DEBUG_CONFIG_SERVER_PORT"
+	configServerNetworkInterfaceEnvVar  = "SPLUNK_DEBUG_CONFIG_SERVER_NETWORK_INTERFACE"
+	defaultConfigServerPort             = "55554"
+	defaultConfigServerNetworkInterface = "localhost"
+	effectivePath                       = "/debug/configz/effective"
+	initialPath                         = "/debug/configz/initial"
 )
 
 type ConfigType int
@@ -138,16 +139,26 @@ func (cs *ConfigServer) start() {
 
 	cs.once.Do(
 		func() {
-			endpoint := defaultConfigServerEndpoint
+			port := defaultConfigServerPort
 			if portOverride, ok := os.LookupEnv(configServerPortEnvVar); ok {
 				if portOverride == "" {
 					// If explicitly set to empty do not start the server.
 					return
 				}
 
-				endpoint = "localhost:" + portOverride
+				port = portOverride
 			}
 
+			networkInterface := defaultConfigServerNetworkInterface
+			if networkInterfaceOverride, ok := os.LookupEnv(configServerNetworkInterfaceEnvVar); ok {
+				if networkInterfaceOverride != "" {
+					networkInterface = networkInterfaceOverride
+				}
+			}
+
+			endpoint := net.JoinHostPort(networkInterface, port)
+			log.Printf("Starting config server at %q\n", endpoint)
+
 			listener, err := net.Listen("tcp", endpoint)
 			if err != nil {
 				if errors.Is(err, syscall.EADDRINUSE) {

diff --git a/internal/configconverter/config_server_test.go b/internal/configconverter/config_server_test.go
@@ -51,23 +51,22 @@ func TestConfigServer_RequireEnvVar(t *testing.T) {
 
 	client := &http.Client{}
 	path := "/debug/configz/initial"
-	_, err := client.Get("http://" + defaultConfigServerEndpoint + path)
+	_, err := client.Get("http://localhost:55554" + path)
 	assert.Error(t, err)
 }
 
 func TestConfigServer_EnvVar(t *testing.T) {
 	alternativePort := strconv.FormatUint(uint64(testutils.GetAvailablePort(t)), 10)
-	require.NoError(t, os.Setenv(configServerEnabledEnvVar, "true"))
-	t.Cleanup(func() {
-		assert.NoError(t, os.Unsetenv(configServerEnabledEnvVar))
-	})
+	alternativeNetworkInterface := "0.0.0.0"
+	t.Setenv(configServerEnabledEnvVar, "true")
 
 	tests := []struct {
-		name          string
-		portEnvVar    string
-		endpoint      string
-		setPortEnvVar bool
-		serverDown    bool
+		name                   string
+		portEnvVar             string
+		networkInterfaceEnvVar string
+		endpoint               string
+		setPortEnvVar          bool
+		serverDown             bool
 	}{
 		{
 			name: "default",
@@ -82,6 +81,11 @@ func TestConfigServer_EnvVar(t *testing.T) {
 			portEnvVar: alternativePort,
 			endpoint:   "http://localhost:" + alternativePort,
 		},
+		{
+			name:                   "change_networkInterface",
+			networkInterfaceEnvVar: alternativeNetworkInterface,
+			endpoint:               "http://0.0.0.0:55554",
+		},
 	}
 
 	for _, tt := range tests {
@@ -97,10 +101,10 @@ func TestConfigServer_EnvVar(t *testing.T) {
 			}
 
 			if tt.portEnvVar != "" || tt.setPortEnvVar {
-				require.NoError(t, os.Setenv(configServerPortEnvVar, tt.portEnvVar))
-				defer func() {
-					assert.NoError(t, os.Unsetenv(configServerPortEnvVar))
-				}()
+				t.Setenv(configServerPortEnvVar, tt.portEnvVar)
+			}
+			if tt.portEnvVar != "" || tt.setPortEnvVar {
+				t.Setenv(configServerNetworkInterfaceEnvVar, tt.networkInterfaceEnvVar)
 			}
 
 			cs := NewConfigServer()
@@ -115,7 +119,7 @@ func TestConfigServer_EnvVar(t *testing.T) {
 
 			endpoint := tt.endpoint
 			if endpoint == "" {
-				endpoint = "http://" + defaultConfigServerEndpoint
+				endpoint = "http://localhost:55554"
 			}
 
 			path := "/debug/configz/initial"
@@ -180,7 +184,7 @@ func TestConfigServer_Serve(t *testing.T) {
 }
 
 func assertValidYAMLPages(t *testing.T, expected map[string]any, path string) {
-	url := "http://" + defaultConfigServerEndpoint + path
+	url := "http://localhost:55554" + path
 
 	client := &http.Client{}