Use cron expression to set update intevals #88 #46

cmd/podsync/main.go

@@ -2,12 +2,15 @@ package main
 
 import (
 	"context"
+	"fmt"
+	"net/http"
 	"os"
 	"os/signal"
 	"syscall"
 	"time"
 
 	"github.com/jessevdk/go-flags"
+	"github.com/robfig/cron/v3"
 	log "github.com/sirupsen/logrus"
 	"golang.org/x/sync/errgroup"
 
@@ -91,10 +94,6 @@ func main() {
 		log.WithError(err).Fatal("failed to open database")
 	}
 
-	// Queue of feeds to update
-	updates := make(chan *config.Feed, 16)
-	defer close(updates)
-
 	// Run updater thread
 	log.Debug("creating updater")
 	updater, err := NewUpdater(cfg, downloader, database)
@@ -102,42 +101,46 @@ func main() {
 		log.WithError(err).Fatal("failed to create updater")
 	}
 
+	c := cron.New(cron.WithChain(cron.SkipIfStillRunning(nil)))
+
 	group.Go(func() error {
-		for {
-			select {
-			case feed := <-updates:
+		defer func() {
+			log.Info("shutting down cron")
+			c.Stop()
+		}()
+
+		for _, feed := range cfg.Feeds {
+			if feed.CronSchedule == "" {
+				feed.CronSchedule = fmt.Sprintf("@every %s", feed.UpdatePeriod.String())
+			}
+
+			_, err = c.AddFunc(feed.CronSchedule, func() {
+				log.Debugf("adding %q to update queue", feed.URL)
+
 				if err := updater.Update(ctx, feed); err != nil {
 					log.WithError(err).Errorf("failed to update feed: %s", feed.URL)
 				}
-			case <-ctx.Done():
-				return ctx.Err()
-			}
-		}
-	})
+			})
 
-	// Run wait goroutines for each feed configuration
-	for _, feed := range cfg.Feeds {
-		_feed := feed
-		group.Go(func() error {
-			log.Debugf("-> %s (update every %s)", _feed.URL, _feed.UpdatePeriod)
+			if err != nil {
+				log.WithError(err).Fatalf("can't create cron task for feed: %s", feed.ID)
+			}
+
+			log.Debugf("-> %s (update '%s')", feed.URL, feed.CronSchedule)
 
 			// Perform initial update after CLI restart
-			updates <- _feed
-
-			timer := time.NewTicker(_feed.UpdatePeriod.Duration)
-			defer timer.Stop()
-
-			for {
-				select {
-				case <-timer.C:
-					log.Debugf("adding %q to update queue", _feed.URL)
-					updates <- _feed
-				case <-ctx.Done():
-					return ctx.Err()
-				}
+			if err := updater.Update(ctx, feed); err != nil {
+				log.WithError(err).Errorf("failed to update feed: %s", feed.URL)
 			}
-		})
-	}
+		}
+
+		c.Start()
+
+		for {
+			<-ctx.Done()
+			return ctx.Err()
+		}
+	})
 
 	// Run web server
 	srv := NewServer(cfg)
@@ -167,7 +170,7 @@ func main() {
 		}
 	})
 
-	if err := group.Wait(); err != nil && err != context.Canceled {
+	if err := group.Wait(); err != nil && (err != context.Canceled && err != http.ErrServerClosed) {
 		log.WithError(err).Error("wait error")
 	}