Commits on Apr 29, 2023

1. App.Run: Respect Shutdowner ExitCode (uber-go#1075) …

   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.

   

   abhinav authored Apr 29, 2023
   Configuration menu

   • View commit details
   • Copy full SHA for 8f5597f
   • Browse repository at this point

   Copy the full SHA

   8f5597f View commit details

   Browse the repository at this point in the history

2. test: Shutdown from fx.Invoke with App.Start …

   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.

   

   abhinav committed Apr 29, 2023
   Configuration menu

   • View commit details
   • Copy full SHA for d54a944
   • Browse repository at this point

   Copy the full SHA

   d54a944 View commit details

   Browse the repository at this point in the history

3. Support Shutdown from fx.Invoke after App.Start …

   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

   

   abhinav committed Apr 29, 2023
   Configuration menu

   • View commit details
   • Copy full SHA for fd94f3f
   • Browse repository at this point

   Copy the full SHA

   fd94f3f View commit details

   Browse the repository at this point in the history