move cron parse into feed.ShouldExecute

src/feeds/http.go

@@ -2,9 +2,30 @@ package feeds
 
 import (
 	"context"
+	"fmt"
 	"io"
+	"time"
+
+	"github.com/robfig/cron/v3"
 )
 
+func (feed Feed) ShouldExecute() (bool, error) {
+	schedule, err := cron.NewParser(
+		cron.SecondOptional |
+			cron.Minute |
+			cron.Hour |
+			cron.Dom |
+			cron.Month |
+			cron.Dow |
+			cron.Descriptor,
+	).Parse(feed.Version.Cron)
+	if err != nil {
+		return false, fmt.Errorf("illegal cron %q", feed.Version.Cron)
+	}
+	next := schedule.Next(feed.Execution.Executed)
+	return time.Now().Before(next), nil
+}
+
 func (feed Feed) Fetch(ctx context.Context) (Items, error) {
 	return nil, io.EOF
 }