From 78150a738fec9d078fd0f8b3a8ddc2ada6fe344a Mon Sep 17 00:00:00 2001
From: andres-portainer <91705312+andres-portainer@users.noreply.github.com>
Date: Wed, 16 Mar 2022 10:33:15 -0300
Subject: [PATCH] fix(scheduler): fix a data race in the scheduler EE-2716
 (#6629)

---
 api/scheduler/scheduler.go      |  9 +++++++++
 api/scheduler/scheduler_test.go | 17 +++++++++++++++++
 2 files changed, 26 insertions(+)

diff --git a/api/scheduler/scheduler.go b/api/scheduler/scheduler.go
index 529574f0c..bb4ce5461 100644
--- a/api/scheduler/scheduler.go
+++ b/api/scheduler/scheduler.go
@@ -4,6 +4,7 @@ import (
 	"context"
 	"log"
 	"strconv"
+	"sync"
 	"time"
 
 	"github.com/pkg/errors"
@@ -14,6 +15,7 @@ import (
 type Scheduler struct {
 	crontab    *cron.Cron
 	activeJobs map[cron.EntryID]context.CancelFunc
+	mu         sync.Mutex
 }
 
 func NewScheduler(ctx context.Context) *Scheduler {
@@ -45,11 +47,13 @@ func (s *Scheduler) Shutdown() error {
 	ctx := s.crontab.Stop()
 	<-ctx.Done()
 
+	s.mu.Lock()
 	for _, job := range s.crontab.Entries() {
 		if cancel, ok := s.activeJobs[job.ID]; ok {
 			cancel()
 		}
 	}
+	s.mu.Unlock()
 
 	err := ctx.Err()
 	if err == context.Canceled {
@@ -65,9 +69,12 @@ func (s *Scheduler) StopJob(jobID string) error {
 		return errors.Wrapf(err, "failed convert jobID %q to int", jobID)
 	}
 	entryID := cron.EntryID(id)
+
+	s.mu.Lock()
 	if cancel, ok := s.activeJobs[entryID]; ok {
 		cancel()
 	}
+	s.mu.Unlock()
 
 	return nil
 }
@@ -87,7 +94,9 @@ func (s *Scheduler) StartJobEvery(duration time.Duration, job func() error) stri
 
 	entryID := s.crontab.Schedule(cron.Every(duration), j)
 
+	s.mu.Lock()
 	s.activeJobs[entryID] = cancel
+	s.mu.Unlock()
 
 	go func(entryID cron.EntryID) {
 		<-ctx.Done()
diff --git a/api/scheduler/scheduler_test.go b/api/scheduler/scheduler_test.go
index b7159a1a1..56377b4bf 100644
--- a/api/scheduler/scheduler_test.go
+++ b/api/scheduler/scheduler_test.go
@@ -2,6 +2,7 @@ package scheduler
 
 import (
 	"context"
+	"errors"
 	"fmt"
 	"testing"
 	"time"
@@ -101,3 +102,19 @@ func Test_CanTerminateAllJobs_ByCancellingParentContext(t *testing.T) {
 	<-ctx.Done()
 	assert.False(t, workDone, "job shouldn't had a chance to run")
 }
+
+func Test_StartJobEvery_Concurrently(t *testing.T) {
+	ctx, cancel := context.WithTimeout(context.Background(), 2*jobInterval)
+	s := NewScheduler(ctx)
+
+	f := func() error {
+		return errors.New("error")
+	}
+
+	go s.StartJobEvery(jobInterval, f)
+	s.StartJobEvery(jobInterval, f)
+
+	cancel()
+
+	<-ctx.Done()
+}