Merge branch 'master' into parser-options

Author: lukescott

cron.go

@@ -3,6 +3,8 @@
 package cron
 
 import (
+	"log"
+	"runtime"
 	"sort"
 	"time"
 )
@@ -16,6 +18,8 @@ type Cron struct {
 	add      chan *Entry
 	snapshot chan []*Entry
 	running  bool
+	ErrorLog *log.Logger
+	location *time.Location
 }
 
 // Job is an interface for submitted cron jobs.
@@ -66,14 +70,21 @@ func (s byTime) Less(i, j int) bool {
 	return s[i].Next.Before(s[j].Next)
 }
 
-// New returns a new Cron job runner.
+// New returns a new Cron job runner, in the Local time zone.
 func New() *Cron {
+	return NewWithLocation(time.Now().Location())
+}
+
+// NewWithLocation returns a new Cron job runner.
+func NewWithLocation(location *time.Location) *Cron {
 	return &Cron{
 		entries:  nil,
 		add:      make(chan *Entry),
 		stop:     make(chan struct{}),
 		snapshot: make(chan []*Entry),
 		running:  false,
+		ErrorLog: nil,
+		location: location,
 	}
 }
 
@@ -87,7 +98,7 @@ func (c *Cron) AddFunc(spec string, cmd func()) error {
 	return c.AddJob(spec, FuncJob(cmd))
 }
 
-// AddFunc adds a Job to the Cron to be run on the given schedule.
+// AddJob adds a Job to the Cron to be run on the given schedule.
 func (c *Cron) AddJob(spec string, cmd Job) error {
 	schedule, err := Parse(spec)
 	if err != nil {
@@ -121,17 +132,37 @@ func (c *Cron) Entries() []*Entry {
 	return c.entrySnapshot()
 }
 
-// Start the cron scheduler in its own go-routine.
+// Location gets the time zone location
+func (c *Cron) Location() *time.Location {
+	return c.location
+}
+
+// Start the cron scheduler in its own go-routine, or no-op if already started.
 func (c *Cron) Start() {
+	if c.running {
+		return
+	}
 	c.running = true
 	go c.run()
 }
 
+func (c *Cron) runWithRecovery(j Job) {
+	defer func() {
+		if r := recover(); r != nil {
+			const size = 64 << 10
+			buf := make([]byte, size)
+			buf = buf[:runtime.Stack(buf, false)]
+			c.logf("cron: panic running job: %v\n%s", r, buf)
+		}
+	}()
+	j.Run()
+}
+
 // Run the scheduler.. this is private just due to the need to synchronize
 // access to the 'running' state variable.
 func (c *Cron) run() {
 	// Figure out the next activation times for each entry.
-	now := time.Now().Local()
+	now := time.Now().In(c.location)
 	for _, entry := range c.entries {
 		entry.Next = entry.Schedule.Next(now)
 	}
@@ -149,32 +180,44 @@ func (c *Cron) run() {
 			effective = c.entries[0].Next
 		}
 
+		timer := time.NewTimer(effective.Sub(now))
 		select {
-		case now = <-time.After(effective.Sub(now)):
+		case now = <-timer.C:
 			// Run every entry whose next time was this effective time.
 			for _, e := range c.entries {
 				if e.Next != effective {
 					break
 				}
-				go e.Job.Run()
+				go c.runWithRecovery(e.Job)
 				e.Prev = e.Next
-				e.Next = e.Schedule.Next(effective)
+				e.Next = e.Schedule.Next(now)
 			}
 			continue
 
 		case newEntry := <-c.add:
 			c.entries = append(c.entries, newEntry)
-			newEntry.Next = newEntry.Schedule.Next(now)
+			newEntry.Next = newEntry.Schedule.Next(time.Now().In(c.location))
 
 		case <-c.snapshot:
 			c.snapshot <- c.entrySnapshot()
 
 		case <-c.stop:
+			timer.Stop()
 			return
 		}
 
 		// 'now' should be updated after newEntry and snapshot cases.
-		now = time.Now().Local()
+		now = time.Now().In(c.location)
+		timer.Stop()
+	}
+}
+
+// Logs an error to stderr or to the configured error log
+func (c *Cron) logf(format string, args ...interface{}) {
+	if c.ErrorLog != nil {
+		c.ErrorLog.Printf(format, args...)
+	} else {
+		log.Printf(format, args...)
 	}
 }
 

cron_test.go

@@ -12,6 +12,38 @@ import (
 // compensate for a few milliseconds of runtime.
 const ONE_SECOND = 1*time.Second + 10*time.Millisecond
 
+func TestFuncPanicRecovery(t *testing.T) {
+	cron := New()
+	cron.Start()
+	defer cron.Stop()
+	cron.AddFunc("* * * * * ?", func() { panic("YOLO") })
+
+	select {
+	case <-time.After(ONE_SECOND):
+		return
+	}
+}
+
+type DummyJob struct{}
+
+func (d DummyJob) Run() {
+	panic("YOLO")
+}
+
+func TestJobPanicRecovery(t *testing.T) {
+	var job DummyJob
+
+	cron := New()
+	cron.Start()
+	defer cron.Stop()
+	cron.AddJob("* * * * * ?", job)
+
+	select {
+	case <-time.After(ONE_SECOND):
+		return
+	}
+}
+
 // Start and stop cron with no entries.
 func TestNoEntries(t *testing.T) {
 	cron := New()
@@ -77,6 +109,22 @@ func TestAddWhileRunning(t *testing.T) {
 	}
 }
 
+// Test for #34. Adding a job after calling start results in multiple job invocations
+func TestAddWhileRunningWithDelay(t *testing.T) {
+	cron := New()
+	cron.Start()
+	defer cron.Stop()
+	time.Sleep(5 * time.Second)
+	var calls = 0
+	cron.AddFunc("* * * * * *", func() { calls += 1 })
+
+	<-time.After(ONE_SECOND)
+	if calls != 1 {
+		fmt.Printf("called %d times, expected 1\n", calls)
+		t.Fail()
+	}
+}
+
 // Test timing with Entries.
 func TestSnapshotEntries(t *testing.T) {
 	wg := &sync.WaitGroup{}
@@ -189,6 +237,33 @@ func TestLocalTimezone(t *testing.T) {
 	}
 }
 
+// Test that the cron is run in the given time zone (as opposed to local).
+func TestNonLocalTimezone(t *testing.T) {
+	wg := &sync.WaitGroup{}
+	wg.Add(1)
+
+	loc, err := time.LoadLocation("Atlantic/Cape_Verde")
+	if err != nil {
+		fmt.Printf("Failed to load time zone Atlantic/Cape_Verde: %+v", err)
+		t.Fail()
+	}
+
+	now := time.Now().In(loc)
+	spec := fmt.Sprintf("%d %d %d %d %d ?",
+		now.Second()+1, now.Minute(), now.Hour(), now.Day(), now.Month())
+
+	cron := NewWithLocation(loc)
+	cron.AddFunc(spec, func() { wg.Done() })
+	cron.Start()
+	defer cron.Stop()
+
+	select {
+	case <-time.After(ONE_SECOND):
+		t.FailNow()
+	case <-wait(wg):
+	}
+}
+
 // Test that calling stop before start silently returns without
 // blocking the stop channel.
 func TestStopWithoutStart(t *testing.T) {