fixed: shut down the server when stdin is closed

Author: strowk

.github/workflows/test.yaml

@@ -19,4 +19,5 @@ jobs:
       - run: cd examples/k8s_contexts_resources && go test
       - run: cd examples/list_current_dir_files_tool && go test
       - run: cd examples/list_k8s_contexts_tool && go test
+      - run: cd tests/lifecycle && go test
       - run: go test ./...

pkg/app/foxy_app.go

@@ -218,8 +218,10 @@ func (f *Builder) provideServerLifecycle(transport server.Transport) fx.Option {
 					)
 					if err != nil {
 						f.transportError = err
-						_ = shutdowner.Shutdown()
 					}
+
+					// shutdown the server when transport is done
+					_ = shutdowner.Shutdown()
 				}()
 				return nil
 			},

pkg/stdio/stdio_transport.go

@@ -5,6 +5,7 @@ import (
 	"context"
 	"errors"
 	"io"
+	"log"
 	"os"
 
 	foxyevent "github.com/strowk/foxy-contexts/pkg/foxy_event"
@@ -92,6 +93,7 @@ func (s *stdioTransport) run(
 				}
 			}
 		}
+		log.Printf("stopped reading responses")
 		close(s.stoppedReadingResponses)
 	}()
 
@@ -115,22 +117,45 @@ func (s *stdioTransport) run(
 		close(s.stoppedReadingInput)
 	}()
 
-	<-s.shuttingDown
+	// wait for either shutting down or stopped reading input
+	select {
+	case <-s.shuttingDown:
+		// if we got shutting down signal,
+		// we need to wait until we stop reading input,
+		// which waits for shutdown by itself
+		<-s.stoppedReadingInput
+	case <-s.stoppedReadingInput:
+		// if we stopped reading input, we can now initiate shutdown
+		close(s.shuttingDown)
+	}
+
+	// wait until we stop reading responses,
+	// before signaling that we are stopped
 	<-s.stoppedReadingResponses
-	<-s.stoppedReadingInput
 
 	close(s.stopped)
-
 	return nil
 }
 
 func (s *stdioTransport) Shutdown(ctx context.Context) error {
-	close(s.shuttingDown)
+	safeClose(s.shuttingDown)
 
+	// this waits either till we are stopped or we cannot wait anymore
 	select {
 	case <-s.stopped:
 		return nil
 	case <-ctx.Done():
 		return ctx.Err()
 	}
 }
+
+func safeClose(ch chan struct{}) {
+	defer func() {
+		if r := recover(); r != nil {
+			// it is possible to panic if channel is already closed
+			// in which case we just go on, as it is possible that
+			// Shutdown would be called soon after transport is stopped
+		}
+	}()
+	close(ch)
+}

tests/lifecycle/go.mod

@@ -0,0 +1,17 @@
+module github.com/strowk/foxy-contexts/tests/lifecycle
+
+replace github.com/strowk/foxy-contexts => ../../
+
+go 1.23.3
+
+require (
+	github.com/strowk/foxy-contexts v0.0.0-00010101000000-000000000000
+	go.uber.org/fx v1.23.0
+	go.uber.org/zap v1.27.0
+)
+
+require (
+	go.uber.org/dig v1.18.0 // indirect
+	go.uber.org/multierr v1.10.0 // indirect
+	golang.org/x/sys v0.21.0 // indirect
+)

tests/lifecycle/go.sum

@@ -0,0 +1,20 @@
+github.com/davecgh/go-spew v1.1.2-0.20180830191138-d8f796af33cc h1:U9qPSI2PIWSS1VwoXQT9A3Wy9MM3WgvqSxFWenqJduM=
+github.com/davecgh/go-spew v1.1.2-0.20180830191138-d8f796af33cc/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/pmezard/go-difflib v1.0.1-0.20181226105442-5d4384ee4fb2 h1:Jamvg5psRIccs7FGNTlIRMkT8wgtp5eCXdBlqhYGL6U=
+github.com/pmezard/go-difflib v1.0.1-0.20181226105442-5d4384ee4fb2/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/stretchr/testify v1.9.0 h1:HtqpIVDClZ4nwg75+f6Lvsy/wHu+3BoSGCbBAcpTsTg=
+github.com/stretchr/testify v1.9.0/go.mod h1:r2ic/lqez/lEtzL7wO/rwa5dbSLXVDPFyf8C91i36aY=
+go.uber.org/dig v1.18.0 h1:imUL1UiY0Mg4bqbFfsRQO5G4CGRBec/ZujWTvSVp3pw=
+go.uber.org/dig v1.18.0/go.mod h1:Us0rSJiThwCv2GteUN0Q7OKvU7n5J4dxZ9JKUXozFdE=
+go.uber.org/fx v1.23.0 h1:lIr/gYWQGfTwGcSXWXu4vP5Ws6iqnNEIY+F/aFzCKTg=
+go.uber.org/fx v1.23.0/go.mod h1:o/D9n+2mLP6v1EG+qsdT1O8wKopYAsqZasju97SDFCU=
+go.uber.org/goleak v1.3.0 h1:2K3zAYmnTNqV73imy9J1T3WC+gmCePx2hEGkimedGto=
+go.uber.org/goleak v1.3.0/go.mod h1:CoHD4mav9JJNrW/WLlf7HGZPjdw8EucARQHekz1X6bE=
+go.uber.org/multierr v1.10.0 h1:S0h4aNzvfcFsC3dRF1jLoaov7oRaKqRGC/pUEJ2yvPQ=
+go.uber.org/multierr v1.10.0/go.mod h1:20+QtiLqy0Nd6FdQB9TLXag12DsQkrbs3htMFfDN80Y=
+go.uber.org/zap v1.27.0 h1:aJMhYGrd5QSmlpLMr2MftRKl7t8J8PTZPA732ud/XR8=
+go.uber.org/zap v1.27.0/go.mod h1:GB2qFLM7cTU87MWRP2mPIjqfIDnGu+VIO4V/SdhGo2E=
+golang.org/x/sys v0.21.0 h1:rF+pYz3DAGSQAxAu1CbC7catZg4ebC4UIeIhKxBZvws=
+golang.org/x/sys v0.21.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
+gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
+gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

tests/lifecycle/lifecycle.go

@@ -0,0 +1,32 @@
+package main
+
+import (
+	"github.com/strowk/foxy-contexts/pkg/app"
+	"github.com/strowk/foxy-contexts/pkg/stdio"
+	"go.uber.org/fx"
+	"go.uber.org/fx/fxevent"
+	"go.uber.org/zap"
+)
+
+func main() {
+	app.
+		NewBuilder().
+		// setting up server
+		WithName("great-tool-server").
+		WithVersion("0.0.1").
+		WithTransport(stdio.NewTransport()).
+		// Configuring fx logging to only show errors
+		WithFxOptions(
+			fx.Provide(func() *zap.Logger {
+				cfg := zap.NewDevelopmentConfig()
+				cfg.Level.SetLevel(zap.ErrorLevel)
+				logger, _ := cfg.Build()
+				return logger
+			}),
+			fx.Option(fx.WithLogger(
+				func(logger *zap.Logger) fxevent.Logger {
+					return &fxevent.ZapLogger{Logger: logger}
+				},
+			)),
+		).Run()
+}

tests/lifecycle/lifecycle_test.go

@@ -0,0 +1,37 @@
+package main
+
+import (
+	"os"
+	"os/exec"
+	"testing"
+	"time"
+)
+
+func TestStartStop(t *testing.T) {
+	cmd := exec.Command("go", "run", "lifecycle.go")
+	stdin, err := cmd.StdinPipe()
+	if err != nil {
+		t.Fatal(err)
+	}
+	cmd.Stderr = os.Stderr
+	processStopped := make(chan struct{})
+	go func() {
+		defer close(processStopped)
+		cmd.Run()
+	}()
+
+	// this should cause process to exit
+	err = stdin.Close()
+	if err != nil {
+		t.Error(err)
+		return
+	}
+
+	timer := time.NewTimer(10 * time.Second)
+	select {
+	case <-processStopped:
+		// process exited
+	case <-timer.C:
+		t.Error("process did not exit in time")
+	}
+}