fix(windows-agent): Avoid leaking proservices Manager on app teardown (…

…#703)

When we call agent.Quit, we don't wait for the proServices to perform
their cleanup. This means that the process can exit while the Landscape,
registry watcher or database are in the middle of an operation.

This PR fixes this, somewhat: It guarantees to exit the process after
proservices.Stop returns. We trust that the implementation of the
teardown of these proservices is implemented properly (I gave it a quick
glance and it seems to be the case).

This problem also affected tests, as the proServices could be writing to
disk while t.Cleanup tries to delete the temp directory, causing a race
and then a test error.

---

Example test failure due to this:
https://github.com/canonical/ubuntu-pro-for-wsl/actions/runs/8436243216/job/23103334236?pr=702#step:7:63

Here, the proservices manager is still writing logs while we try to
remove the log file, even though we already called Quit on the app.

go.work.sum

@@ -863,6 +863,7 @@ golang.org/x/crypto v0.15.0/go.mod h1:4ChreQoLWfG3xLDer1WdlH5NdlQ3+mwnQq1YTKY+72
 golang.org/x/crypto v0.16.0/go.mod h1:gCAAfMLgwOJRpTjQ2zCCt2OcSfYMTeZVSRtQlPC7Nq4=
 golang.org/x/crypto v0.18.0/go.mod h1:R0j02AL6hcrfOiy9T4ZYp/rcWeMxM3L6QYxlOuEG1mg=
 golang.org/x/crypto v0.19.0/go.mod h1:Iy9bg/ha4yyC70EfRS8jz+B6ybOBKMaSxLj6P6oBDfU=
+golang.org/x/crypto v0.21.0/go.mod h1:0BP7YvVV9gBbVKyeTG0Gyn+gZm94bibOW5BjDEYAOMs=
 golang.org/x/exp v0.0.0-20230905200255-921286631fa9/go.mod h1:S2oDrQGGwySpoQPVqRShND87VCbxmc6bL1Yd2oYrm6k=
 golang.org/x/lint v0.0.0-20210508222113-6edffad5e616/go.mod h1:3xt1FjdF8hUf6vQPIChWIBhFzV8gjjsPE/fR3IyQdNY=
 golang.org/x/mod v0.5.0/go.mod h1:5OXOZSfqPIIbmVBIIKWRFfZjPR0E5r58TLhUjH0a2Ro=
@@ -942,6 +943,7 @@ golang.org/x/term v0.13.0/go.mod h1:LTmsnFJwVN6bCy1rVCoS+qHT1HhALEFxKncY3WNNh4U=
 golang.org/x/term v0.15.0/go.mod h1:BDl952bC7+uMoWR75FIrCDx79TPU9oHkTZ9yRbYOrX0=
 golang.org/x/term v0.16.0/go.mod h1:yn7UURbUtPyrVJPGPq404EukNFxcm/foM+bV/bfcDsY=
 golang.org/x/term v0.17.0/go.mod h1:lLRBjIVuehSbZlaOtGMbcMncT+aqLLLmKrsjNrUguwk=
+golang.org/x/term v0.18.0/go.mod h1:ILwASektA3OnRv7amZ1xhE/KTR+u50pbXfZ03+6Nx58=
 golang.org/x/text v0.3.5/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
 golang.org/x/text v0.3.8/go.mod h1:E6s5w1FMmriuDzIBO73fBruAKo1PCIq6d2Q6DHfQ8WQ=
 golang.org/x/text v0.5.0/go.mod h1:mrYo+phRRbMaCq/xk9113O4dZlRixOauAjOtrjsXDZ8=

windows-agent/cmd/ubuntu-pro-agent/agent/agent.go

@@ -36,7 +36,8 @@ type App struct {
 	viper   *viper.Viper
 	config  daemonConfig
 
-	daemon *daemon.Daemon
+	daemon      *daemon.Daemon
+	proServices *proservices.Manager
 
 	ready chan struct{}
 }
@@ -125,7 +126,7 @@ func (a *App) serve(args ...option) error {
 
 	log.Debugf(ctx, "Agent private directory: %s", privateDir)
 
-	proservice, err := proservices.New(ctx,
+	proservices, err := proservices.New(ctx,
 		publicDir,
 		privateDir,
 		proservices.WithRegistry(opt.registry),
@@ -134,9 +135,9 @@ func (a *App) serve(args ...option) error {
 		close(a.ready)
 		return err
 	}
-	defer proservice.Stop(ctx)
+	a.proServices = &proservices
 
-	a.daemon = daemon.New(ctx, proservice.RegisterGRPCServices, publicDir)
+	a.daemon = daemon.New(ctx, proservices.RegisterGRPCServices, publicDir)
 
 	close(a.ready)
 
@@ -184,6 +185,7 @@ func (a *App) Quit() {
 		return
 	}
 	a.daemon.Quit(context.Background(), false)
+	a.proServices.Stop(context.Background())
 }
 
 // WaitReady signals when the daemon is ready