app.Done() not notified when shutdown is called before all OnStart hooks have completed
phsym opened this issue · 6 comments
Describe the bug
When Shutdowner.Shutdown() is called before all OnStart hooks have been called, app.Done() and app.Wait() channels opened after the shutdown is triggered will never get notified.
I'm using v1.19.2
To Reproduce
Below test fails while I believe it should not
func TestFxShutdownOnStart_Fail(t *testing.T) {
srv := fx.New(fx.Invoke(
fx.Annotate(
func(s fx.Shutdowner) fx.Shutdowner { return s },
fx.OnStart(
func(s fx.Shutdowner) error {
go func() {
s.Shutdown()
}()
time.Sleep(1 * time.Second)
return nil
}),
fx.OnStop(func() {
fmt.Printf("\n####### Stop hook called ########\n\n")
}),
),
))
assert.NoError(t, srv.Start(context.Background()))
time.Sleep(1 * time.Second)
ctx, cancelFunc := context.WithTimeout(context.Background(), 5*time.Second)
defer cancelFunc()
select {
case <-srv.Done():
case <-ctx.Done():
assert.NoError(t, ctx.Err(), "srv.Done() timed out")
}
assert.NoError(t, srv.Stop(context.Background()))
}output:
[Fx] PROVIDE fx.Lifecycle <= go.uber.org/fx.New.func1()
[Fx] PROVIDE fx.Shutdowner <= go.uber.org/fx.(*App).shutdowner-fm()
[Fx] PROVIDE fx.DotGraph <= go.uber.org/fx.(*App).dotGraph-fm()
[Fx] INVOKE fx.Annotate(XXXXXXX_test.TestFxShutdownOnStart_Fail.func1()
[Fx] HOOK OnStart go.uber.org/fx.(*lifecycleHookAnnotation).buildHookInstaller.func1.1() executing (caller: go.uber.org/fx.(*lifecycleHookAnnotation).buildHookInstaller.func1)
[Fx] HOOK OnStart go.uber.org/fx.(*lifecycleHookAnnotation).buildHookInstaller.func1.1() called by go.uber.org/fx.(*lifecycleHookAnnotation).buildHookInstaller.func1 ran successfully in 1.000347365s
[Fx] RUNNING
[Fx] HOOK OnStop go.uber.org/fx.(*lifecycleHookAnnotation).buildHookInstaller.func1.1() executing (caller: go.uber.org/fx.(*lifecycleHookAnnotation).buildHookInstaller.func1)
####### Stop hook called ########
[Fx] HOOK OnStop go.uber.org/fx.(*lifecycleHookAnnotation).buildHookInstaller.func1.1() called by go.uber.org/fx.(*lifecycleHookAnnotation).buildHookInstaller.func1 ran successfully in 15.141µs
--- FAIL: TestFxShutdownOnStart_Fail (7.00s)
XXXXXXX_test.go:89:
Error Trace: XXXXXXX_test.go:89
Error: Received unexpected error:
context deadline exceeded
Test: TestFxShutdownOnStart_Fail
Messages: srv.Done() timed out
FAIL
The workaround is to acquire the srv.Done() channel before starting the application
func TestFxShutdownOnStart_OK(t *testing.T) {
srv := fx.New(fx.Invoke(
fx.Annotate(
func(s fx.Shutdowner) fx.Shutdowner { return s },
fx.OnStart(
func(s fx.Shutdowner) error {
go func() {
s.Shutdown()
}()
time.Sleep(1 * time.Second)
return nil
}),
fx.OnStop(func() {
fmt.Printf("\n####### Stop hook called ########\n\n")
}),
),
))
ch := srv.Done()
assert.NoError(t, srv.Start(context.Background()))
time.Sleep(1 * time.Second)
ctx, cancelFunc := context.WithTimeout(context.Background(), 5*time.Second)
defer cancelFunc()
select {
case <-ch:
case <-ctx.Done():
assert.NoError(t, ctx.Err(), "srv.Done() timed out")
}
assert.NoError(t, srv.Stop(context.Background()))
}Expected behavior
Both test cases above should pass.
Additional context
A quick investigation led me to the conclusion that app.receiver is started after all OnStart hooks have been run as seen here https://github.com/uber-go/fx/blob/master/app.go#L681
recv.last is resetted to nil when receiver is started as seen here https://github.com/uber-go/fx/blob/master/signal.go#L112
but recv.last holds the last received shutdown signal, which is used to immediately notify Done() channels created after shutdown has been triggered, so any channel opened after that will never know that the app has been shut down.
This is not a duplicate.
Internally tracked with GO-1939
This should be fixed in the latest release.