fix: Race when writing to a closed pipe

kylecarbs · kylecarbs · commit 46b24f78ab53 · 2022-06-01T02:50:04.000Z
This is such an intermittent race it's difficult to track,
but regardless this is an improvement to the code.
diff --git a/provisionersdk/serve.go b/provisionersdk/serve.go
@@ -31,7 +31,7 @@ func Serve(ctx context.Context, server proto.DRPCProvisionerServer, options *Ser
 	if options.Listener == nil {
 		config := yamux.DefaultConfig()
 		config.LogOutput = io.Discard
-		stdio, err := yamux.Server(readWriteCloser{
+		stdio, err := yamux.Server(&readWriteCloser{
 			ReadCloser: os.Stdin,
 			Writer:     os.Stdout,
 		}, config)
@@ -54,6 +54,9 @@ func Serve(ctx context.Context, server proto.DRPCProvisionerServer, options *Ser
 	// short-lived processes that can be executed concurrently.
 	err = srv.Serve(ctx, options.Listener)
 	if err != nil {
+		if errors.Is(err, io.EOF) {
+			return nil
+		}
 		if errors.Is(err, context.Canceled) {
 			return nil
 		}
@@ -67,3 +70,8 @@ func Serve(ctx context.Context, server proto.DRPCProvisionerServer, options *Ser
 	}
 	return nil
 }
+
+type readWriteCloser struct {
+	io.ReadCloser
+	io.Writer
+}
diff --git a/provisionersdk/transport.go b/provisionersdk/transport.go
@@ -3,6 +3,7 @@ package provisionersdk
 import (
 	"context"
 	"io"
+	"net"
 
 	"github.com/hashicorp/yamux"
 	"storj.io/drpc"
@@ -17,22 +18,14 @@ const (
 
 // TransportPipe creates an in-memory pipe for dRPC transport.
 func TransportPipe() (*yamux.Session, *yamux.Session) {
-	clientReader, clientWriter := io.Pipe()
-	serverReader, serverWriter := io.Pipe()
+	c1, c2 := net.Pipe()
 	yamuxConfig := yamux.DefaultConfig()
 	yamuxConfig.LogOutput = io.Discard
-	client, err := yamux.Client(&readWriteCloser{
-		ReadCloser: clientReader,
-		Writer:     serverWriter,
-	}, yamuxConfig)
+	client, err := yamux.Client(c1, yamuxConfig)
 	if err != nil {
 		panic(err)
 	}
-
-	server, err := yamux.Server(&readWriteCloser{
-		ReadCloser: serverReader,
-		Writer:     clientWriter,
-	}, yamuxConfig)
+	server, err := yamux.Server(c2, yamuxConfig)
 	if err != nil {
 		panic(err)
 	}
@@ -44,11 +37,6 @@ func Conn(session *yamux.Session) drpc.Conn {
 	return &multiplexedDRPC{session}
 }
 
-type readWriteCloser struct {
-	io.ReadCloser
-	io.Writer
-}
-
 // Allows concurrent requests on a single dRPC connection.
 // Required for calling functions concurrently.
 type multiplexedDRPC struct {
