Fix stdout premature EOF

Never close attached stream before both stdout and stderr have written
all their buffered contents. Remove stdinCloser because it is not needed
any more as the stream is closed anyway after attach has finished.

Fixes #3631

Signed-off-by: Andy Goldstein <agoldste@redhat.com>

daemon/attach.go

@@ -83,7 +83,6 @@ func (daemon *Daemon) ContainerAttach(job *engine.Job) engine.Status {
 		var (
 			cStdin           io.ReadCloser
 			cStdout, cStderr io.Writer
-			cStdinCloser     io.Closer
 		)
 
 		if stdin {
@@ -94,7 +93,6 @@ func (daemon *Daemon) ContainerAttach(job *engine.Job) engine.Status {
 				io.Copy(w, job.Stdin)
 			}()
 			cStdin = r
-			cStdinCloser = job.Stdin
 		}
 		if stdout {
 			cStdout = job.Stdout
@@ -103,7 +101,7 @@ func (daemon *Daemon) ContainerAttach(job *engine.Job) engine.Status {
 			cStderr = job.Stderr
 		}
 
-		<-daemon.attach(&container.StreamConfig, container.Config.OpenStdin, container.Config.StdinOnce, container.Config.Tty, cStdin, cStdinCloser, cStdout, cStderr)
+		<-daemon.attach(&container.StreamConfig, container.Config.OpenStdin, container.Config.StdinOnce, container.Config.Tty, cStdin, cStdout, cStderr)
 		// If we are in stdinonce mode, wait for the process to end
 		// otherwise, simply return
 		if container.Config.StdinOnce && !container.Config.Tty {
@@ -113,7 +111,7 @@ func (daemon *Daemon) ContainerAttach(job *engine.Job) engine.Status {
 	return engine.StatusOK
 }
 
-func (daemon *Daemon) attach(streamConfig *StreamConfig, openStdin, stdinOnce, tty bool, stdin io.ReadCloser, stdinCloser io.Closer, stdout io.Writer, stderr io.Writer) chan error {
+func (daemon *Daemon) attach(streamConfig *StreamConfig, openStdin, stdinOnce, tty bool, stdin io.ReadCloser, stdout io.Writer, stderr io.Writer) chan error {
 	var (
 		cStdout, cStderr io.ReadCloser
 		nJobs            int
@@ -130,10 +128,10 @@ func (daemon *Daemon) attach(streamConfig *StreamConfig, openStdin, stdinOnce, t
 			go func() {
 				log.Debugf("attach: stdin: begin")
 				defer log.Debugf("attach: stdin: end")
-				// No matter what, when stdin is closed (io.Copy unblock), close stdout and stderr
 				if stdinOnce && !tty {
 					defer cStdin.Close()
 				} else {
+					// No matter what, when stdin is closed (io.Copy unblock), close stdout and stderr
 					defer func() {
 						if cStdout != nil {
 							cStdout.Close()
@@ -173,9 +171,6 @@ func (daemon *Daemon) attach(streamConfig *StreamConfig, openStdin, stdinOnce, t
 				if stdinOnce && stdin != nil {
 					defer stdin.Close()
 				}
-				if stdinCloser != nil {
-					defer stdinCloser.Close()
-				}
 				_, err := io.Copy(stdout, cStdout)
 				if err == io.ErrClosedPipe {
 					err = nil
@@ -189,9 +184,6 @@ func (daemon *Daemon) attach(streamConfig *StreamConfig, openStdin, stdinOnce, t
 	} else {
 		// Point stdout of container to a no-op writer.
 		go func() {
-			if stdinCloser != nil {
-				defer stdinCloser.Close()
-			}
 			if cStdout, err := streamConfig.StdoutPipe(); err != nil {
 				log.Errorf("attach: stdout pipe: %s", err)
 			} else {
@@ -213,9 +205,6 @@ func (daemon *Daemon) attach(streamConfig *StreamConfig, openStdin, stdinOnce, t
 				if stdinOnce && stdin != nil {
 					defer stdin.Close()
 				}
-				if stdinCloser != nil {
-					defer stdinCloser.Close()
-				}
 				_, err := io.Copy(stderr, cStderr)
 				if err == io.ErrClosedPipe {
 					err = nil
@@ -229,10 +218,6 @@ func (daemon *Daemon) attach(streamConfig *StreamConfig, openStdin, stdinOnce, t
 	} else {
 		// Point stderr at a no-op writer.
 		go func() {
-			if stdinCloser != nil {
-				defer stdinCloser.Close()
-			}
-
 			if cStderr, err := streamConfig.StderrPipe(); err != nil {
 				log.Errorf("attach: stdout pipe: %s", err)
 			} else {
@@ -251,8 +236,6 @@ func (daemon *Daemon) attach(streamConfig *StreamConfig, openStdin, stdinOnce, t
 			}
 		}()
 
-		// FIXME: how to clean up the stdin goroutine without the unwanted side effect
-		// of closing the passed stdin? Add an intermediary io.Pipe?
 		for i := 0; i < nJobs; i++ {
 			log.Debugf("attach: waiting for job %d/%d", i+1, nJobs)
 			if err := <-errors; err != nil {

daemon/exec.go

@@ -155,7 +155,6 @@ func (d *Daemon) ContainerExecStart(job *engine.Job) engine.Status {
 	var (
 		cStdin           io.ReadCloser
 		cStdout, cStderr io.Writer
-		cStdinCloser     io.Closer
 		execName         = job.Args[0]
 	)
 
@@ -183,10 +182,10 @@ func (d *Daemon) ContainerExecStart(job *engine.Job) engine.Status {
 		r, w := io.Pipe()
 		go func() {
 			defer w.Close()
+			defer log.Debugf("Closing buffered stdin pipe")
 			io.Copy(w, job.Stdin)
 		}()
 		cStdin = r
-		cStdinCloser = job.Stdin
 	}
 	if execConfig.OpenStdout {
 		cStdout = job.Stdout
@@ -204,7 +203,7 @@ func (d *Daemon) ContainerExecStart(job *engine.Job) engine.Status {
 		execConfig.StreamConfig.stdinPipe = ioutils.NopWriteCloser(ioutil.Discard) // Silently drop stdin
 	}
 
-	attachErr := d.attach(&execConfig.StreamConfig, execConfig.OpenStdin, false, execConfig.ProcessConfig.Tty, cStdin, cStdinCloser, cStdout, cStderr)
+	attachErr := d.attach(&execConfig.StreamConfig, execConfig.OpenStdin, false, execConfig.ProcessConfig.Tty, cStdin, cStdout, cStderr)
 
 	execErr := make(chan error)
 

integration-cli/docker_cli_run_test.go

@@ -4,6 +4,7 @@ import (
 	"bufio"
 	"bytes"
 	"fmt"
+	"io"
 	"io/ioutil"
 	"net"
 	"os"
@@ -2446,3 +2447,46 @@ func TestRunVolumesCleanPaths(t *testing.T) {
 
 	logDone("run - volume paths are cleaned")
 }
+
+// Regression test for #3631
+func TestRunSlowStdoutConsumer(t *testing.T) {
+	defer deleteAllContainers()
+
+	c := exec.Command("/bin/bash", "-c", dockerBinary+` run --rm -i busybox /bin/sh -c "dd if=/dev/zero of=/foo bs=1024 count=2000 &>/dev/null; catv /foo"`)
+
+	stdout, err := c.StdoutPipe()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if err := c.Start(); err != nil {
+		t.Fatal(err)
+	}
+	n, err := consumeSlow(stdout, 10000, 5*time.Millisecond)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	expected := 2 * 1024 * 2000
+	if n != expected {
+		t.Fatalf("Expected %d, got %d", expected, n)
+	}
+
+	logDone("run - slow consumer")
+}
+
+func consumeSlow(reader io.Reader, chunkSize int, interval time.Duration) (n int, err error) {
+	buffer := make([]byte, chunkSize)
+	for {
+		var readBytes int
+		readBytes, err = reader.Read(buffer)
+		n += readBytes
+		if err != nil {
+			if err == io.EOF {
+				err = nil
+			}
+			return
+		}
+		time.Sleep(interval)
+	}
+}