Move the context cancelled error message into a debug statement (el…

…astic#187)

* Move the `context cancelled` error message into a debug statement

This code improve the error reporting when Elastic Agent is stopped
through the pass context. This move the state reporting closer to the
execution of the request. Error related to the request would still be
logged as error and will change the internal state to non healthy.

Fixes: elastic#154

CHANGELOG.next.asciidoc

@@ -96,6 +96,7 @@
 - Allow agent containers to use basic auth to create a service token. {pull}29651[29651]
 - Fix issue where a failing artifact verification does not remove the bad artifact. {pull}30281[30281]
 - Reduce Elastic Agent shut down time by stopping processes concurrently {pull}29650[29650]
+- Move `context cancelled` error from fleet gateway into debug level. {pull}187[187]
 
 ==== New features
 

internal/pkg/agent/application/gateway/fleet/fleet_gateway.go

@@ -165,8 +165,6 @@ func (f *fleetGateway) worker() {
 			// jitter to help better distribute the load from a fleet of agents.
 			resp, err := f.doExecute()
 			if err != nil {
-				f.log.Error(err)
-				f.statusReporter.Update(state.Failed, err.Error(), nil)
 				continue
 			}
 
@@ -198,24 +196,34 @@ func (f *fleetGateway) worker() {
 
 func (f *fleetGateway) doExecute() (*fleetapi.CheckinResponse, error) {
 	f.backoff.Reset()
+
+	// Guard if the context is stopped by a out of bound call,
+	// this mean we are rebooting to change the log level or the system is shutting us down.
 	for f.bgContext.Err() == nil {
-		// TODO: wrap with timeout context
 		f.log.Debugf("Checking started")
 		resp, err := f.execute(f.bgContext)
 		if err != nil {
 			f.log.Errorf("Could not communicate with fleet-server Checking API will retry, error: %s", err)
 			if !f.backoff.Wait() {
-				return nil, errors.New(
+				// Something bad has happened and we log it and we should update our current state.
+				err := errors.New(
 					"execute retry loop was stopped",
 					errors.TypeNetwork,
 					errors.M(errors.MetaKeyURI, f.client.URI()),
 				)
+
+				f.log.Error(err)
+				f.statusReporter.Update(state.Failed, err.Error(), nil)
+				return nil, err
 			}
 			continue
 		}
+		// Request was successful, return the collected actions.
 		return resp, nil
 	}
 
+	// This mean that the next loop was cancelled because of the context, we should return the error
+	// but we should not log it, because we are in the process of shutting down.
 	return nil, f.bgContext.Err()
 }