feat: add torznab feed support (#246)

* feat(torznab): initial impl

* feat: torznab processing

* feat: torznab more scheduling

* feat: feeds web

* feat(feeds): create on indexer create

* feat(feeds): update migration

* feat(feeds): restart on update

* feat(feeds): set cron schedule

* feat(feeds): use basic empty state

* chore: remove duplicate migrations

* feat: parse release size from torznab

* chore: cleanup unused code

internal/scheduler/service.go

@@ -0,0 +1,87 @@
+package scheduler
+
+import (
+	"fmt"
+
+	"github.com/robfig/cron/v3"
+	"github.com/rs/zerolog/log"
+)
+
+type Service interface {
+	Start()
+	Stop()
+	AddJob(job cron.Job, interval string, identifier string) (int, error)
+	RemoveJobByID(id cron.EntryID) error
+	RemoveJobByIdentifier(id string) error
+}
+
+type service struct {
+	cron *cron.Cron
+
+	jobs map[string]cron.EntryID
+}
+
+func NewService() Service {
+	return &service{
+		cron: cron.New(cron.WithChain(
+			cron.Recover(cron.DefaultLogger),
+		)),
+		jobs: map[string]cron.EntryID{},
+	}
+}
+
+func (s *service) Start() {
+	log.Debug().Msg("scheduler.Start")
+
+	s.cron.Start()
+	return
+}
+
+func (s *service) Stop() {
+	log.Debug().Msg("scheduler.Stop")
+	s.cron.Stop()
+	return
+}
+func (s *service) AddJob(job cron.Job, interval string, identifier string) (int, error) {
+
+	id, err := s.cron.AddJob(interval, cron.NewChain(
+		cron.SkipIfStillRunning(cron.DiscardLogger)).Then(job),
+	)
+	if err != nil {
+		return 0, fmt.Errorf("scheduler: add job failed: %w", err)
+	}
+
+	log.Debug().Msgf("scheduler.AddJob: job successfully added: %v", id)
+
+	// add to job map
+	s.jobs[identifier] = id
+
+	return int(id), nil
+}
+
+func (s *service) RemoveJobByID(id cron.EntryID) error {
+	v, ok := s.jobs[""]
+	if !ok {
+		return nil
+	}
+
+	s.cron.Remove(v)
+	return nil
+}
+
+func (s *service) RemoveJobByIdentifier(id string) error {
+	v, ok := s.jobs[id]
+	if !ok {
+		return nil
+	}
+
+	log.Debug().Msgf("scheduler.Remove: removing job: %v", id)
+
+	// remove from cron
+	s.cron.Remove(v)
+
+	// remove from jobs map
+	delete(s.jobs, id)
+
+	return nil
+}