Register callback to call when event cannot be sent

v2/bugsnag.go

@@ -253,23 +253,23 @@ func init() {
 			Notify:   "https://notify.bugsnag.com",
 			Sessions: "https://sessions.bugsnag.com",
 		},
-		Hostname:            device.GetHostname(),
-		AppType:             "",
-		AppVersion:          "",
-		AutoCaptureSessions: true,
-		ReleaseStage:        "",
-		ParamsFilters:       []string{"password", "secret", "authorization", "cookie", "access_token"},
-		SourceRoot:          sourceRoot,
-		ProjectPackages:     []string{"main*"},
-		NotifyReleaseStages: nil,
-		Logger:              log.New(os.Stdout, log.Prefix(), log.Flags()),
-		PanicHandler:        defaultPanicHandler,
-		Transport:           http.DefaultTransport,
-		NumGoroutines:       10,
-		MaxPendingReports:   1000,
-		GoroutinePooler:        goroutinePoolCall,
-
-		flushSessionsOnRepanic: true,
+		Hostname:            		 device.GetHostname(),
+		AppType:             		 "",
+		AppVersion:          		 "",
+		AutoCaptureSessions: 		 true,
+		ReleaseStage:        		 "",
+		ParamsFilters:       		 []string{"password", "secret", "authorization", "cookie", "access_token"},
+		SourceRoot:          		 sourceRoot,
+		ProjectPackages:     		 []string{"main*"},
+		NotifyReleaseStages: 		 nil,
+		Logger:              		 log.New(os.Stdout, log.Prefix(), log.Flags()),
+		PanicHandler:        		 defaultPanicHandler,
+		Transport:           		 http.DefaultTransport,
+		NumGoroutines:       		 10,
+		MaxPendingReports:   		 1000,
+		GoroutinePooler:     		 goroutinePoolCall,
+		GoroutinePoolerCallback: nil,
+		flushSessionsOnRepanic:  true,
 	})
 	updateSessionConfig()
 }

v2/bugsnag_test.go

@@ -139,7 +139,7 @@ type testPublisher struct {
 	sync bool
 }
 
-func (tp *testPublisher) publishReport(p *payload, goroutinePool GoroutinePooler) error {
+func (tp *testPublisher) publishReport(p *payload, goroutinePool GoroutinePooler, poolerCallback GoroutinePoolerCallback) error {
 	tp.sync = p.Synchronous
 	return nil
 }

v2/configuration.go

@@ -117,9 +117,12 @@ type Configuration struct {
 	// fatal crash.
 	flushSessionsOnRepanic bool
 
-	// This thread pooler will be used when sending async events
-	// to minimize resource usage.
+	// This thread pooler is used when sending async events to minimize resource usage.
 	GoroutinePooler
+
+	// This callback is used when async pooler fails to send events.
+	// User can handle persistence or resending of event body provided in JSON format.
+	GoroutinePoolerCallback
 	// TODO: remember to update the update() function when modifying this struct
 }
 
@@ -178,6 +181,9 @@ func (config *Configuration) update(other *Configuration) *Configuration {
 	if other.GoroutinePooler != nil {
 		config.GoroutinePooler = other.GoroutinePooler
 	}
+	if other.GoroutinePoolerCallback != nil {
+		config.GoroutinePoolerCallback = other.GoroutinePoolerCallback
+	}
 
 	if other.AutoCaptureSessions != nil {
 		config.AutoCaptureSessions = other.AutoCaptureSessions

v2/notifier.go

@@ -70,9 +70,9 @@ func (notifier *Notifier) NotifySync(err error, sync bool, rawData ...interface{
 	skipFrames := 1
 	event, config := newEvent(append(rawData, errors.New(err, skipFrames), sync), notifier)
 
-	// Never block, start throwing away errors if we have too many.
+	// Never block, default behaviour is to start throwing away errors if we have too many.
 	e := middleware.Run(event, config, func() error {
-		return publisher.publishReport(&payload{event, config}, notifier.Config.GoroutinePooler)
+		return publisher.publishReport(&payload{event, config}, notifier.Config.GoroutinePooler, notifier.Config.GoroutinePoolerCallback)
 	})
 
 	if e != nil {

v2/report_publisher.go

@@ -3,13 +3,20 @@ package bugsnag
 import "fmt"
 
 type reportPublisher interface {
-	publishReport(*payload, GoroutinePooler) error
+	publishReport(*payload, GoroutinePooler, GoroutinePoolerCallback) error
 }
 
 type defaultReportPublisher struct{}
+
+// GoroutinePooler type describes user's goroutine pooler's "Submit" function
 type GoroutinePooler func(eventSendFunc func()) error
 
-func (*defaultReportPublisher) publishReport(p *payload, goroutinePool GoroutinePooler) error {
+// GoroutinePoolerCallback is a function to call in case sending event failed.
+// Event payload in JSON form is passed as an argument.
+// By default events are dropped and not sent again.
+type GoroutinePoolerCallback func(payloadJSON []byte)
+
+func (*defaultReportPublisher) publishReport(p *payload, goroutinePool GoroutinePooler, failCallback GoroutinePoolerCallback) error {
 	p.logf("notifying bugsnag: %s", p.Message)
 	if !p.notifyInReleaseStage() {
 		return fmt.Errorf("not notifying in %s", p.ReleaseStage)
@@ -25,7 +32,14 @@ func (*defaultReportPublisher) publishReport(p *payload, goroutinePool Goroutine
 		}
 	})
 	if err != nil {
-		return fmt.Errorf("could not notify bugsnag via async pool")
+		p.logf("could not notify bugsnag via async pool")
+		if (failCallback != nil) {
+			payloadJSON, errJSON := p.MarshalJSON()
+			if errJSON != nil {
+				failCallback(payloadJSON)
+			}
+		}
+		return err
 	}
 	return nil
 }