fix(scheduler): the session cleanup generator is reset too often (#2220)

This causes the "fair" scheduler to run it too often in the detriment of other generators.
The intention was to run it every 2 hours but the measurement unit for 7200 was not specified.

Add more logs, including showing a generator name, in order to troubleshoot this kind of issues easier in the future.

Signed-off-by: Andrei Aaron <aaaron@luxoft.com>

pkg/extensions/extension_scrub.go

@@ -55,6 +55,10 @@ type taskGenerator struct {
 	done     bool
 }
 
+func (gen *taskGenerator) Name() string {
+	return "ScrubGenerator"
+}
+
 func (gen *taskGenerator) Next() (scheduler.Task, error) {
 	repo, err := gen.imgStore.GetNextRepository(gen.lastRepo)
 	if err != nil {

pkg/extensions/imagetrust/image_trust.go

@@ -200,6 +200,10 @@ type sigValidityTaskGenerator struct {
 	log       log.Logger
 }
 
+func (gen *sigValidityTaskGenerator) Name() string {
+	return "SignatureValidationGenerator"
+}
+
 func (gen *sigValidityTaskGenerator) Next() (scheduler.Task, error) {
 	if len(gen.repos) == 0 {
 		ctx := context.Background()

pkg/extensions/search/cve/scan.go

@@ -115,6 +115,10 @@ func (gen *scanTaskGenerator) isScheduled(digest string) bool {
 	return ok
 }
 
+func (gen *scanTaskGenerator) Name() string {
+	return "CVEScanGenerator"
+}
+
 func (gen *scanTaskGenerator) Next() (scheduler.Task, error) {
 	// metaRB requires us to use a context for authorization
 	userAc := reqCtx.NewUserAccessControl()

pkg/extensions/search/cve/update.go

@@ -46,6 +46,10 @@ type DBUpdateTaskGenerator struct {
 	lock         *sync.Mutex
 }
 
+func (gen *DBUpdateTaskGenerator) Name() string {
+	return "CVEDBUpdateGenerator"
+}
+
 func (gen *DBUpdateTaskGenerator) Next() (scheduler.Task, error) {
 	var newTask scheduler.Task
 

pkg/extensions/sync/sync.go

@@ -90,6 +90,10 @@ func NewTaskGenerator(service Service, log log.Logger) *TaskGenerator {
 	}
 }
 
+func (gen *TaskGenerator) Name() string {
+	return "SyncGenerator"
+}
+
 func (gen *TaskGenerator) Next() (scheduler.Task, error) {
 	if err := gen.Service.SetNextAvailableURL(); err != nil {
 		return nil, err