Avoid panics on exit

Update pyRunner to ensure that the process is forcibly killed if it does not
respond to the quit request. The standard streams are closed by Cmd.Wait so we
don't have to.

bagit_test.go

@@ -139,3 +139,13 @@ Tag-File-Character-Encoding: UTF-8
 		assert.ErrorContains(t, err, "does not exist")
 	})
 }
+
+func TestCleanup(t *testing.T) {
+	t.Parallel()
+
+	b, err := bagit.NewBagIt()
+	assert.NilError(t, err)
+
+	err = b.Cleanup()
+	assert.NilError(t, err)
+}

go.mod

@@ -3,8 +3,8 @@ module github.com/artefactual-labs/bagit-gython
 go 1.21
 
 require (
-	github.com/kluctl/go-embed-python v0.0.0-3.12.3-20240415-1
-	golang.org/x/sync v0.7.0
+	github.com/kluctl/go-embed-python v0.0.0-3.12.3-20240415-2
+	golang.org/x/sync v0.8.0
 	gotest.tools/v3 v3.5.1
 )
 

go.sum

@@ -5,8 +5,8 @@ github.com/gobwas/glob v0.2.3 h1:A4xDbljILXROh+kObIiy5kIaPYD8e96x1tgBhUI5J+Y=
 github.com/gobwas/glob v0.2.3/go.mod h1:d3Ez4x06l9bZtSvzIay5+Yzi0fmZzPgnTbPcKjJAkT8=
 github.com/google/go-cmp v0.5.9 h1:O2Tfq5qg4qc4AmwVlvv0oLiVAGB7enBSJ2x2DqQFi38=
 github.com/google/go-cmp v0.5.9/go.mod h1:17dUlkBOakJ0+DkrSSNjCkIjxS6bF9zb3elmeNGIjoY=
-github.com/kluctl/go-embed-python v0.0.0-3.12.3-20240415-1 h1:IX2O3LJUL0AjYsROGZ4aNENTEb3c/Ll/0b9Yb/8P61Q=
-github.com/kluctl/go-embed-python v0.0.0-3.12.3-20240415-1/go.mod h1:9kqX8IjRCNh4ppXxlKGtLN+QFuvsdSsNGKsTLgdSNRw=
+github.com/kluctl/go-embed-python v0.0.0-3.12.3-20240415-2 h1:JcYhVgX7jFN8QcoBxx8/kLxUyeUzE/JnGf5ntulNPPM=
+github.com/kluctl/go-embed-python v0.0.0-3.12.3-20240415-2/go.mod h1:9kqX8IjRCNh4ppXxlKGtLN+QFuvsdSsNGKsTLgdSNRw=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/rogpeppe/go-internal v1.12.0 h1:exVL4IDcn6na9z1rAb56Vxr+CgyK3nn3O+epU5NdKM8=
@@ -17,8 +17,8 @@ github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+
 github.com/stretchr/testify v1.7.0/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
 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=
-golang.org/x/sync v0.7.0 h1:YsImfSBoP9QPYL0xyKJPq0gcaJdG3rInoqxTWbfQu9M=
-golang.org/x/sync v0.7.0/go.mod h1:Czt+wKu1gCyEFDUtn0jG5QVvpJ6rzVqr5aXyt9drQfk=
+golang.org/x/sync v0.8.0 h1:3NFvSEYkUoMifnESzZl15y791HH1qU2xm6eCJU5ZPXQ=
+golang.org/x/sync v0.8.0/go.mod h1:Czt+wKu1gCyEFDUtn0jG5QVvpJ6rzVqr5aXyt9drQfk=
 golang.org/x/sys v0.0.0-20220715151400-c0bba94af5f8/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.21.0 h1:rF+pYz3DAGSQAxAu1CbC7catZg4ebC4UIeIhKxBZvws=
 golang.org/x/sys v0.21.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=

runner.go

@@ -10,6 +10,7 @@ import (
 	"os/exec"
 	"sync"
 	"sync/atomic"
+	"time"
 
 	"github.com/kluctl/go-embed-python/python"
 )
@@ -135,31 +136,43 @@ func (r *pyRunner) quit() error {
 	r.mu.Lock()
 	defer r.mu.Unlock()
 
-	_, err := r.stdin.Write([]byte(`{"name": "exit"}`))
+	var err error
+	if r.stdin != nil {
+		_, err = r.stdin.Write([]byte(`{"name": "exit"}`))
+	}
 
 	return err
 }
 
-func (i *pyRunner) stop() error {
+func (r *pyRunner) stop() error {
 	var e error
 
-	if err := i.quit(); err != nil {
-		e = errors.Join(e, err)
-	}
-
-	if err := i.stdin.Close(); err != nil {
-		e = errors.Join(e, err)
-	}
-
-	if err := i.stdout.Close(); err != nil {
+	if err := r.quit(); err != nil {
 		e = errors.Join(e, err)
 	}
 
-	if err := i.cmd.Process.Kill(); err != nil {
-		e = errors.Join(e, err)
+	// Wait up to a second, otherwise force to exit immediately.
+	if closed := wait(&r.wg, time.Second); !closed {
+		if err := r.cmd.Process.Kill(); err != nil {
+			e = errors.Join(e, err)
+		}
 	}
 
-	i.wg.Wait()
+	r.wg.Wait()
 
 	return e
 }
+
+func wait(wg *sync.WaitGroup, timeout time.Duration) bool {
+	done := make(chan struct{})
+	go func() {
+		wg.Wait()
+		close(done)
+	}()
+	select {
+	case <-done:
+		return true
+	case <-time.After(timeout):
+		return false
+	}
+}