[chore][connector/datadogconnector] Fix connector traceToMetrics life…

…cycle (#31811)

**Description:**
Currently, calling `Shutdown` on the `traceToMetricConnector` requires
on `Start` being called before, as the `Shutdown` relies on goroutines
which are spawned during `Start`. This causes the connector to hang if a
call to `Shutdown` is made without a call to `Start`. This PR adds a
`isStarted` field to the `traceToMetricConnector` struct, which tracks
whether `Start` was called. If it was not, it makes the call to
`Shutdown` a no-op.

**Link to tracking Issue:** #30487

**Testing:** <Describe what testing was performed and which tests were
added.>

**Documentation:** <Describe the documentation added.>

---------

Co-authored-by: Antoine Toulme <antoine@toulme.name>

connector/datadogconnector/connector.go

@@ -42,6 +42,9 @@ type traceToMetricConnector struct {
 
 	// exit specifies the exit channel, which will be closed upon shutdown.
 	exit chan struct{}
+
+	// isStarted tracks whether Start() has been called.
+	isStarted bool
 }
 
 var _ component.Component = (*traceToMetricConnector)(nil) // testing that the connectorImp properly implements the type Component interface
@@ -91,11 +94,17 @@ func (c *traceToMetricConnector) Start(_ context.Context, _ component.Host) erro
 	c.logger.Info("Starting datadogconnector")
 	c.agent.Start()
 	go c.run()
+	c.isStarted = true
 	return nil
 }
 
 // Shutdown implements the component.Component interface.
 func (c *traceToMetricConnector) Shutdown(context.Context) error {
+	if !c.isStarted {
+		// Note: it is not necessary to manually close c.exit, c.in and c.agent.(*datadog.TraceAgent).exit channels as these are unused.
+		c.logger.Info("Requested shutdown, but not started, ignoring.")
+		return nil
+	}
 	c.logger.Info("Shutting down datadog connector")
 	c.logger.Info("Stopping datadog agent")
 	// stop the agent and wait for the run loop to exit

connector/datadogconnector/go.mod

@@ -13,6 +13,7 @@ require (
 	github.com/open-telemetry/opentelemetry-collector-contrib/processor/tailsamplingprocessor v0.96.0
 	github.com/stretchr/testify v1.9.0
 	go.opentelemetry.io/collector/component v0.96.1-0.20240315172937-3b5aee0c7a16
+	go.opentelemetry.io/collector/confmap v0.96.1-0.20240315172937-3b5aee0c7a16
 	go.opentelemetry.io/collector/connector v0.96.1-0.20240315172937-3b5aee0c7a16
 	go.opentelemetry.io/collector/consumer v0.96.1-0.20240315172937-3b5aee0c7a16
 	go.opentelemetry.io/collector/exporter v0.96.1-0.20240315172937-3b5aee0c7a16
@@ -148,7 +149,6 @@ require (
 	go.opentelemetry.io/collector/config/configtelemetry v0.96.1-0.20240315172937-3b5aee0c7a16 // indirect
 	go.opentelemetry.io/collector/config/configtls v0.96.1-0.20240315172937-3b5aee0c7a16 // indirect
 	go.opentelemetry.io/collector/config/internal v0.96.1-0.20240315172937-3b5aee0c7a16 // indirect
-	go.opentelemetry.io/collector/confmap v0.96.1-0.20240315172937-3b5aee0c7a16 // indirect
 	go.opentelemetry.io/collector/confmap/converter/expandconverter v0.96.1-0.20240315172937-3b5aee0c7a16 // indirect
 	go.opentelemetry.io/collector/confmap/provider/envprovider v0.96.1-0.20240315172937-3b5aee0c7a16 // indirect
 	go.opentelemetry.io/collector/confmap/provider/fileprovider v0.96.1-0.20240315172937-3b5aee0c7a16 // indirect

connector/datadogconnector/metadata.yaml

@@ -11,5 +11,3 @@ status:
     emeritus: [gbbr]
 
 tests:
-  skip_lifecycle: true
-  skip_shutdown: true