yuxh/gearman-go
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Ability to exit work loop gracefully

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This change adds the ability to call Shutdown on a gearman-go worker which causes the
worker to wait for all currently active jobs to finish and then close the connection.

It does this by keeping tracking of the number of currently active transactions, disallowing
new job creation, and using a WaitGroup to wait for all active jobs to finish.
This commit is contained in:
Kyle Vigen 2014-06-10 11:37:10 -07:00
parent 320155c608
commit 8cdaef9752
2 changed files with 190 additions and 35 deletions
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67
worker/worker.go
View File

@ -18,11 +18,15 @@ const (
// It can connect to multi-server and grab jobs.
type Worker struct {
sync.Mutex
agents []*agent
funcs jobFuncs
in chan *inPack
running bool
ready bool
agents []*agent
funcs jobFuncs
in chan *inPack
running bool
ready bool
shuttingDown bool
activeJobs int
// Used during shutdown to wait for all active jobs to finish
finishedDraining sync.WaitGroup
Id string
ErrorHandler ErrorHandler
@ -43,6 +47,7 @@ func New(limit int) (worker *Worker) {
funcs: make(jobFuncs),
in: make(chan *inPack, queueSize),
}
worker.finishedDraining.Add(1)
if limit != Unlimited {
worker.limit = make(chan bool, limit-1)
}
@ -137,7 +142,9 @@ func (worker *Worker) handleInPack(inpack *inPack) {
case dtNoJob:
inpack.a.PreSleep()
case dtNoop:
inpack.a.Grab()
if !worker.shuttingDown {
inpack.a.Grab()
}
case dtJobAssign, dtJobAssignUniq:
go func() {
if err := worker.exec(inpack); err != nil {
@ -147,7 +154,9 @@ func (worker *Worker) handleInPack(inpack *inPack) {
if worker.limit != nil {
worker.limit <- true
}
inpack.a.Grab()
if !worker.shuttingDown {
inpack.a.Grab()
}
case dtError:
worker.err(inpack.Err())
fallthrough
@ -182,11 +191,11 @@ func (worker *Worker) Ready() (err error) {
// Main loop, block here
// Most of time, this should be evaluated in goroutine.
func (worker *Worker) Work() {
if ! worker.ready {
if !worker.ready {
// didn't run Ready beforehand, so we'll have to do it:
err := worker.Ready()
if err != nil {
panic( err )
panic(err)
}
}
@ -224,6 +233,19 @@ func (worker *Worker) Close() {
}
}
// Shutdown server gracefully. This function will block until all active work has finished.
func (worker *Worker) Shutdown() {
worker.Lock()
worker.shuttingDown = true
if worker.activeJobs == 0 {
worker.finishedDraining.Done()
}
worker.Unlock()
// Wait for the mutex
worker.finishedDraining.Wait()
worker.Close()
}
// Echo
func (worker *Worker) Echo(data []byte) {
outpack := getOutPack()
@ -250,6 +272,29 @@ func (worker *Worker) SetId(id string) {
worker.broadcast(outpack)
}
// IncrementActive increments the count of active jobs. This will return false if no more
// jobs can't be started because the worker is shutting down.
func (worker *Worker) incrementActive() bool {
worker.Lock()
defer worker.Unlock()
if worker.shuttingDown {
return false
}
worker.activeJobs = worker.activeJobs + 1
return true
}
// DecrementActive decrements the count of active jobs. If the process is shutting down
// it will set the finishedDraining flag if there are no more active jobs.
func (worker *Worker) decrementActive() {
worker.Lock()
defer worker.Unlock()
worker.activeJobs = worker.activeJobs - 1
if worker.shuttingDown && worker.activeJobs == 0 {
worker.finishedDraining.Done()
}
}
// inner job executing
func (worker *Worker) exec(inpack *inPack) (err error) {
defer func() {
@ -263,7 +308,11 @@ func (worker *Worker) exec(inpack *inPack) (err error) {
err = ErrUnknown
}
}
worker.decrementActive()
}()
if !worker.incrementActive() {
return
}
f, ok := worker.funcs[inpack.fn]
if !ok {
return fmt.Errorf("The function does not exist: %s", inpack.fn)

148
worker/worker_test.go
View File

@ -1,6 +1,7 @@
package worker
import (
"strconv"
"sync"
"testing"
"time"
@ -62,6 +63,7 @@ func TestWorkerRemoveFunc(t *testing.T) {
}
func TestWork(t *testing.T) {
// TODO: Worth looking at this for shutdown (WaitGroup)
var wg sync.WaitGroup
worker.JobHandler = func(job Job) error {
t.Logf("%s", job.Data())
@ -78,12 +80,11 @@ func TestWork(t *testing.T) {
wg.Wait()
}
func TestWorkerClose(t *testing.T) {
worker.Close()
}
func TestWorkWithoutReady(t * testing.T){
func TestWorkWithoutReady(t *testing.T) {
other_worker := New(Unlimited)
if err := other_worker.AddServer(Network, "127.0.0.1:4730"); err != nil {
@ -94,13 +95,13 @@ func TestWorkWithoutReady(t * testing.T){
}
timeout := make(chan bool, 1)
done := make( chan bool, 1)
done := make(chan bool, 1)
other_worker.JobHandler = func( j Job ) error {
if( ! other_worker.ready ){
t.Error("Worker not ready as expected");
other_worker.JobHandler = func(j Job) error {
if !other_worker.ready {
t.Error("Worker not ready as expected")
}
done <-true
done <- true
return nil
}
go func() {
@ -108,15 +109,15 @@ func TestWorkWithoutReady(t * testing.T){
timeout <- true
}()
go func(){
other_worker.Work();
go func() {
other_worker.Work()
}()
// With the all-in-one Work() we don't know if the
// worker is ready at this stage so we may have to wait a sec:
go func(){
go func() {
tries := 3
for( tries > 0 ){
for tries > 0 {
if other_worker.ready {
other_worker.Echo([]byte("Hello"))
break
@ -129,22 +130,22 @@ func TestWorkWithoutReady(t * testing.T){
}()
// determine if we've finished or timed out:
select{
case <- timeout:
select {
case <-timeout:
t.Error("Test timed out waiting for the worker")
case <- done:
case <-done:
}
}
func TestWorkWithoutReadyWithPanic(t * testing.T){
func TestWorkWithoutReadyWithPanic(t *testing.T) {
other_worker := New(Unlimited)
timeout := make(chan bool, 1)
done := make( chan bool, 1)
done := make(chan bool, 1)
// Going to work with no worker setup.
// when Work (hopefully) calls Ready it will get an error which should cause it to panic()
go func(){
go func() {
defer func() {
if err := recover(); err != nil {
done <- true
@ -153,17 +154,122 @@ func TestWorkWithoutReadyWithPanic(t * testing.T){
t.Error("Work should raise a panic.")
done <- true
}()
other_worker.Work();
other_worker.Work()
}()
go func() {
time.Sleep(2 * time.Second)
timeout <- true
}()
select{
case <- timeout:
select {
case <-timeout:
t.Error("Test timed out waiting for the worker")
case <- done:
case <-done:
}
}
// initWorker creates a worker and adds the localhost server to it
func initWorker(t *testing.T) *Worker {
otherWorker := New(Unlimited)
if err := otherWorker.AddServer(Network, "127.0.0.1:4730"); err != nil {
t.Error(err)
}
return otherWorker
}
// submitEmptyInPack sends an empty inpack with the specified fn name to the worker. It uses
// the first agent of the worker.
func submitEmptyInPack(t *testing.T, worker *Worker, function string) {
if l := len(worker.agents); l != 1 {
t.Error("The worker has no agents")
}
inpack := getInPack()
inpack.dataType = dtJobAssign
inpack.fn = function
inpack.a = worker.agents[0]
worker.in <- inpack
}
// TestShutdownSuccessJob tests that shutdown waits for the currently running job to
// complete.
func TestShutdownSuccessJob(t *testing.T) {
otherWorker := initWorker(t)
output := 0
var wg sync.WaitGroup
successJob := func(job Job) ([]byte, error) {
wg.Done()
// Sleep for 100ms to ensure that the shutdown waits for this to finish
time.Sleep(time.Duration(100 * time.Millisecond))
output = 1
return nil, nil
}
if err := otherWorker.AddFunc("test", successJob, 0); err != nil {
t.Error(err)
}
if err := otherWorker.Ready(); err != nil {
t.Error(err)
return
}
submitEmptyInPack(t, otherWorker, "test")
go otherWorker.Work()
// Wait for the success_job to start so that we know we didn't shutdown before even
// beginning to process the job.
wg.Add(1)
wg.Wait()
otherWorker.Shutdown()
if output != 1 {
t.Error("Expected 1, output was: " + strconv.Itoa(output))
}
}
func TestShutdownFailureJob(t *testing.T) {
otherWorker := initWorker(t)
output := 0
var wg sync.WaitGroup
failureJob := func(job Job) ([]byte, error) {
wg.Done()
// Sleep for 100ms to ensure that shutdown waits for this to finish
time.Sleep(time.Duration(100 * time.Millisecond))
output = 1
return nil, nil //new Error()
}
if err := otherWorker.AddFunc("test", failureJob, 0); err != nil {
t.Error(err)
}
if err := otherWorker.Ready(); err != nil {
t.Error(err)
return
}
submitEmptyInPack(t, otherWorker, "test")
go otherWorker.Work()
// Wait for the success_job to start so that we know we didn't shutdown before even
// beginning to process the job.
wg.Add(1)
wg.Wait()
otherWorker.Shutdown()
if output != 1 {
t.Error("Expected 1, output was: " + strconv.Itoa(output))
}
}
func TestSubmitJobAfterShutdown(t *testing.T) {
otherWorker := initWorker(t)
noRunJob := func(job Job) ([]byte, error) {
t.Error("This job shouldn't have been run")
return nil, nil
}
if err := otherWorker.AddFunc("test", noRunJob, 0); err != nil {
t.Error(err)
}
if err := otherWorker.Ready(); err != nil {
t.Error(err)
return
}
go otherWorker.Work()
otherWorker.Shutdown()
submitEmptyInPack(t, otherWorker, "test")
// Sleep for 100ms to make sure that the job doesn't actually run
time.Sleep(time.Duration(100 * time.Millisecond))
}