limit concurrent jobs MAYBE

scheduler/scheduler.go

@@ -5,13 +5,14 @@ import (
 	"errors"
 	"fmt"
 	"io/ioutil"
+	"regexp"
+	"strings"
+	"time"
+
 	"gitea.inhome.blapointe.com/local/firestormy/config"
 	"gitea.inhome.blapointe.com/local/firestormy/config/ns"
 	"gitea.inhome.blapointe.com/local/firestormy/logger"
 	"gitea.inhome.blapointe.com/local/logb"
-	"regexp"
-	"strings"
-	"time"
 
 	cron "github.com/robfig/cron/v3"
 )
@@ -23,14 +24,32 @@ type Scheduler struct {
 	running map[string]cron.EntryID
 }
 
+type semaphored struct {
+	job cron.Job
+	ch  chan struct{}
+}
+
+func (s semaphored) Run() {
+	s.ch <- struct{}{}
+	s.job.Run()
+	<-s.ch
+}
+
 func New() *Scheduler {
 	l := logger.New()
+	semaphore := make(chan struct{}, 2)
 	c := cron.New(
 		cron.WithLocation(time.Local),
 		cron.WithLogger(l),
 		cron.WithChain(
 			cron.SkipIfStillRunning(l),
 			cron.Recover(l),
+			func(j cron.Job) cron.Job {
+				return semaphored{
+					job: j,
+					ch:  semaphore,
+				}
+			},
 		),
 		cron.WithParser(getParser()),
 	)