Add exitOnWait flag

README.md

@@ -13,6 +13,8 @@ The SPIFFE Helper is a simple utility for fetching X.509 SVID certificates from
 
 If `-config` is not specified, the default value `helper.conf` is assumed. 
 
+The flag `-exitWhenReady` is also supported.
+
 ## Configuration
 The configuration file is an [HCL](https://github.com/hashicorp/hcl) formatted file that defines the following configurations:
 

cmd/spiffe-helper/main.go

@@ -17,24 +17,25 @@ func main() {
 	// 2. Run Sidecar's Daemon
 
 	configFile := flag.String("config", "helper.conf", "<configFile> Configuration file path")
+	exitWhenReady := flag.Bool("exitWhenReady", false, "Exit once the requested objects are retrieved")
 	flag.Parse()
 
 	log := logrus.WithField("system", "spiffe-helper")
 	log.Infof("Using configuration file: %q\n", *configFile)
 
-	if err := startSidecar(*configFile, log); err != nil {
+	if err := startSidecar(*configFile, *exitWhenReady, log); err != nil {
 		log.WithError(err).Error("Exiting due this error")
 		os.Exit(1)
 	}
 
 	log.Infof("Exiting")
 }
 
-func startSidecar(configPath string, log logrus.FieldLogger) error {
+func startSidecar(configPath string, exitWhenReady bool, log logrus.FieldLogger) error {
 	ctx, stop := signal.NotifyContext(context.Background(), os.Interrupt)
 	defer stop()
 
-	spiffeSidecar, err := sidecar.New(configPath, log)
+	spiffeSidecar, err := sidecar.New(configPath, exitWhenReady, log)
 	if err != nil {
 		return fmt.Errorf("Failed to create sidecar: %w", err)
 	}

pkg/sidecar/sidecar.go

@@ -41,7 +41,7 @@ type Sidecar struct {
 }
 
 // New creates a new SPIFFE sidecar
-func New(configPath string, log logrus.FieldLogger) (*Sidecar, error) {
+func New(configPath string, exitWhenReady bool, log logrus.FieldLogger) (*Sidecar, error) {
 	config, err := ParseConfig(configPath)
 	if err != nil {
 		return nil, fmt.Errorf("failed to parse %q: %w", configPath, err)
@@ -68,6 +68,8 @@ func New(configPath string, log logrus.FieldLogger) (*Sidecar, error) {
 		config.Log.Warn("No cmd defined to execute.")
 	}
 
+	config.ExitWhenReady = config.ExitWhenReady || exitWhenReady
+
 	return &Sidecar{
 		config:        config,
 		certReadyChan: make(chan struct{}, 1),

pkg/sidecar/sidecar_test.go

@@ -194,14 +194,22 @@ func TestSidecar_RunDaemon(t *testing.T) {
 
 func TestDefaultAgentAddress(t *testing.T) {
 	log, _ := test.NewNullLogger()
-	spiffeSidecar, err := New("../../test/sidecar/config/helper.conf", log)
+	spiffeSidecar, err := New("../../test/sidecar/config/helper.conf", false, log)
 	require.NoError(t, err)
 	assert.Equal(t, spiffeSidecar.config.AgentAddress, "/tmp/spire-agent/public/api.sock")
 }
+
+func TestExitOnWaitFlag(t *testing.T) {
+	log, _ := test.NewNullLogger()
+	spiffeSidecar, err := New("../../test/sidecar/config/helper.conf", true, log)
+	require.NoError(t, err)
+	assert.Equal(t, spiffeSidecar.config.ExitWhenReady, true)
+}
+
 func TestEnvAgentAddress(t *testing.T) {
 	os.Setenv("SPIRE_AGENT_ADDRESS", "/tmp/spire-agent/public/api.sock")
 	log, _ := test.NewNullLogger()
-	spiffeSidecar, err := New("../../test/sidecar/config/helper.conf", log)
+	spiffeSidecar, err := New("../../test/sidecar/config/helper.conf", false, log)
 	require.NoError(t, err)
 	assert.Equal(t, spiffeSidecar.config.AgentAddress, "/tmp/spire-agent/public/api.sock")
 }
@@ -210,7 +218,7 @@ func TestAgentAddress(t *testing.T) {
 	// This test is used to verify that we get the agent_address of the .conf file instead of the ENV value, if we have both
 	os.Setenv("SPIRE_AGENT_ADDRESS", "/tmp/spire-agent/public/api.sock")
 	log, _ := test.NewNullLogger()
-	spiffeSidecar, err := New("../../test/sidecar/configWithAddress/helper.conf", log)
+	spiffeSidecar, err := New("../../test/sidecar/configWithAddress/helper.conf", false, log)
 	require.NoError(t, err)
 	assert.Equal(t, spiffeSidecar.config.AgentAddress, "/tmp/spire-agent/public/api.sock")
 }