Merge pull request #2150 from mitchellh/f-docker

Docker bug fixes

builder/docker/builder.go

 package docker
 
 import (
+	"log"
+
 	"github.com/mitchellh/multistep"
 	"github.com/mitchellh/packer/common"
 	"github.com/mitchellh/packer/packer"
-	"log"
 )
 
 const BuilderId = "packer.docker"
@@ -31,6 +32,12 @@ func (b *Builder) Run(ui packer.Ui, hook packer.Hook, cache packer.Cache) (packe
 		return nil, err
 	}
 
+	version, err := driver.Version()
+	if err != nil {
+		return nil, err
+	}
+	log.Printf("[DEBUG] Docker version: %s", version.String())
+
 	steps := []multistep.Step{
 		&StepTempDir{},
 		&StepPull{},
@@ -70,8 +77,13 @@ func (b *Builder) Run(ui packer.Ui, hook packer.Hook, cache packer.Cache) (packe
 		return nil, rawErr.(error)
 	}
 
-	var artifact packer.Artifact
+	// If it was cancelled, then just return
+	if _, ok := state.GetOk(multistep.StateCancelled); ok {
+		return nil, nil
+	}
+
 	// No errors, must've worked
+	var artifact packer.Artifact
 	if b.config.Commit {
 		artifact = &ImportArtifact{
 			IdValue:        state.Get("image_id").(string),
@@ -81,6 +93,7 @@ func (b *Builder) Run(ui packer.Ui, hook packer.Hook, cache packer.Cache) (packe
 	} else {
 		artifact = &ExportArtifact{path: b.config.ExportPath}
 	}
+
 	return artifact, nil
 }
 

builder/docker/communicator.go

@@ -15,6 +15,7 @@ import (
 	"time"
 
 	"github.com/ActiveState/tail"
+	"github.com/hashicorp/go-version"
 	"github.com/mitchellh/packer/packer"
 )
 
@@ -22,6 +23,7 @@ type Communicator struct {
 	ContainerId  string
 	HostDir      string
 	ContainerDir string
+	Version      *version.Version
 
 	lock sync.Mutex
 }
@@ -41,7 +43,13 @@ func (c *Communicator) Start(remote *packer.RemoteCmd) error {
 	// This file will store the exit code of the command once it is complete.
 	exitCodePath := outputFile.Name() + "-exit"
 
-	cmd := exec.Command("docker", "attach", c.ContainerId)
+	var cmd *exec.Cmd
+	if c.canExec() {
+		cmd = exec.Command("docker", "exec", "-i", c.ContainerId, "/bin/sh")
+	} else {
+		cmd = exec.Command("docker", "attach", c.ContainerId)
+	}
+
 	stdin_w, err := cmd.StdinPipe()
 	if err != nil {
 		// We have to do some cleanup since run was never called
@@ -117,7 +125,7 @@ func (c *Communicator) UploadDir(dst string, src string, exclude []string) error
 			return os.MkdirAll(hostpath, info.Mode())
 		}
 
-		if info.Mode() & os.ModeSymlink == os.ModeSymlink {
+		if info.Mode()&os.ModeSymlink == os.ModeSymlink {
 			dest, err := os.Readlink(path)
 
 			if err != nil {
@@ -186,6 +194,15 @@ func (c *Communicator) Download(src string, dst io.Writer) error {
 	panic("not implemented")
 }
 
+// canExec tells us whether `docker exec` is supported
+func (c *Communicator) canExec() bool {
+	execConstraint, err := version.NewConstraint(">= 1.4.0")
+	if err != nil {
+		panic(err)
+	}
+	return execConstraint.Check(c.Version)
+}
+
 // Runs the given command and blocks until completion
 func (c *Communicator) run(cmd *exec.Cmd, remote *packer.RemoteCmd, stdin_w io.WriteCloser, outputFile *os.File, exitCodePath string) {
 	// For Docker, remote communication must be serialized since it

builder/docker/config.go

@@ -30,7 +30,7 @@ type Config struct {
 }
 
 func NewConfig(raws ...interface{}) (*Config, []string, error) {
-	c := new(Config)
+	var c Config
 
 	var md mapstructure.Metadata
 	err := config.Decode(&c, &config.DecodeOpts{
@@ -83,5 +83,5 @@ func NewConfig(raws ...interface{}) (*Config, []string, error) {
 		return nil, nil, errs
 	}
 
-	return c, nil, nil
+	return &c, nil, nil
 }

builder/docker/driver.go

@@ -2,6 +2,8 @@ package docker
 
 import (
 	"io"
+
+	"github.com/hashicorp/go-version"
 )
 
 // Driver is the interface that has to be implemented to communicate with
@@ -48,6 +50,9 @@ type Driver interface {
 
 	// Verify verifies that the driver can run
 	Verify() error
+
+	// Version reads the Docker version
+	Version() (*version.Version, error)
 }
 
 // ContainerConfig is the configuration used to start a container.

builder/docker/driver_docker.go

@@ -7,9 +7,11 @@ import (
 	"log"
 	"os"
 	"os/exec"
+	"regexp"
 	"strings"
 	"sync"
 
+	"github.com/hashicorp/go-version"
 	"github.com/mitchellh/packer/packer"
 	"github.com/mitchellh/packer/template/interpolate"
 )
@@ -263,3 +265,17 @@ func (d *DockerDriver) Verify() error {
 
 	return nil
 }
+
+func (d *DockerDriver) Version() (*version.Version, error) {
+	output, err := exec.Command("docker", "-v").Output()
+	if err != nil {
+		return nil, err
+	}
+
+	match := regexp.MustCompile(version.VersionRegexpRaw).FindSubmatch(output)
+	if match == nil {
+		return nil, fmt.Errorf("unknown version: %s", output)
+	}
+
+	return version.NewVersion(string(match[0]))
+}

builder/docker/driver_mock.go

@@ -2,6 +2,8 @@ package docker
 
 import (
 	"io"
+
+	"github.com/hashicorp/go-version"
 )
 
 // MockDriver is a driver implementation that can be used for tests.
@@ -63,6 +65,9 @@ type MockDriver struct {
 	StopCalled   bool
 	StopID       string
 	VerifyCalled bool
+
+	VersionCalled  bool
+	VersionVersion string
 }
 
 func (d *MockDriver) Commit(id string) (string, error) {
@@ -162,3 +167,8 @@ func (d *MockDriver) Verify() error {
 	d.VerifyCalled = true
 	return d.VerifyError
 }
+
+func (d *MockDriver) Version() (*version.Version, error) {
+	d.VersionCalled = true
+	return version.NewVersion(d.VersionVersion)
+}

builder/docker/step_provision.go

@@ -9,14 +9,23 @@ type StepProvision struct{}
 
 func (s *StepProvision) Run(state multistep.StateBag) multistep.StepAction {
 	containerId := state.Get("container_id").(string)
+	driver := state.Get("driver").(Driver)
 	tempDir := state.Get("temp_dir").(string)
 
+	// Get the version so we can pass it to the communicator
+	version, err := driver.Version()
+	if err != nil {
+		state.Put("error", err)
+		return multistep.ActionHalt
+	}
+
 	// Create the communicator that talks to Docker via various
 	// os/exec tricks.
 	comm := &Communicator{
 		ContainerId:  containerId,
 		HostDir:      tempDir,
 		ContainerDir: "/packer-files",
+		Version:      version,
 	}
 
 	prov := common.StepProvision{Comm: comm}