Shutdowner: Support calling from fx.Invoke #1
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abhinav
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We added support for changing the exit code for a Shutdowner with the ExitCode option in uber-go#989, but this was somehow not respected by App.Run. This changes App.Run to use the same underlying machinery (`Wait()`) to decide on the exit code to use. To test this, we add a new internal/e2e submodule that will hold full, end-to-end integration tests. These can be full Fx applications that we run tests against. This is a submodule so that it can have dependencies that are not desirable as direct dependencies of Fx, and it's inside the internal/ directory so that it can consume Fx-internal packages (like testutil). The included regression test verifies the behavior described in uber-go#1074. An Fx program using App.Run, and shut down with Shutdowner.Shutdown and an explicit exit code, does not exit with the requested exit code. Failure before the fix: ``` % go test --- FAIL: TestShutdownExitCode (0.01s) writer.go:40: [Fx] PROVIDE fx.Lifecycle <= go.uber.org/fx.New.func1() writer.go:40: [Fx] PROVIDE fx.Shutdowner <= go.uber.org/fx.(*App).shutdowner-fm() writer.go:40: [Fx] PROVIDE fx.DotGraph <= go.uber.org/fx.(*App).dotGraph-fm() writer.go:40: [Fx] INVOKE go.uber.org/fx/internal/e2e/shutdowner_run_exitcode.main.func1() writer.go:40: [Fx] RUNNING writer.go:40: [Fx] TERMINATED main_test.go:46: Error Trace: [..]/fx/internal/e2e/shutdowner_run_exitcode/main_test.go:46 Error: An error is expected but got nil. Test: TestShutdownExitCode FAIL exit status 1 FAIL go.uber.org/fx/internal/e2e/shutdowner_run_exitcode 0.016s ``` Resolves uber-go#1074 --- There's a follow up to this: #1. It depends on the e2e test machinery, so I'll make a PR out of it once this is merged.
Adds a test for calling Shutdown from an fx.Invoke. This is partially tested in uber-go#1075 already, but as reported in uber-go#1074, it doesn't work if Start is used. This adds a test for that case as well.
App.Start nils out the "last" signal recorded by signalReceivers,
which it otherwise broadcasts to waiters if it was already received.
This is unnecessary especially because there's a discrepancy in behavior
of using App.Start vs App.Run when shutting down from fx.Invoke.
Given a program that calls Shutdown from fx.Invoke,
when we do:
app := fx.New(...)
The shutdowner has already sent the signal, and signalReceivers has
already recorded it.
At that point, whether we call App.Start or App.Run changes behavior:
- If we call App.Run, that calls App.Done (or App.Wait after uber-go#1075),
which gives it back a channel that already has the signal filled in.
It then calls App.Start, waits on the channel--which returns
immediately--and then calls App.Stop.
- If we call App.Start and App.Wait, on the other hand,
Start will clear the signal recorded in signalReceivers,
and then App.Wait will build a channel that will block indefinitely
because Shutdowner.Shutdown will not be called again.
So even though App.Run() and App.Start()+App.Wait() are meant to be
equivalent, this causes a serious discrepancy in behavior.
It makes sense to resolve this by supporting Shutdown from Invoke.
Refs uber-go#1074
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|
Opened upstream: uber-go#1076 |
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App.Start nils out the "last" signal recorded by signalReceivers,
which it otherwise broadcasts to waiters if it was already received.
This is unnecessary especially because there's a discrepancy in behavior
of using App.Start vs App.Run when shutting down from fx.Invoke.
Given a program that calls Shutdown from fx.Invoke,
when we do:
The shutdowner has already sent the signal, and signalReceivers has
already recorded it.
At that point, whether we call App.Start or App.Run changes behavior:
which gives it back a channel that already has the signal filled in.
It then calls App.Start, waits on the channel--which returns
immediately--and then calls App.Stop.
Start will clear the signal recorded in signalReceivers,
and then App.Wait will build a channel that will block indefinitely
because Shutdowner.Shutdown will not be called again.
So even though App.Run() and App.Start()+App.Wait() are meant to be
equivalent, this causes a serious discrepancy in behavior.
It makes sense to resolve this by supporting Shutdown from Invoke.
Refs uber-go#1074