Changed file builder to support content or source file operation

builder/file/builder.go

@@ -6,7 +6,10 @@ any virutalization or network resources, it's very fast and useful for testing.
 */
 
 import (
+	"fmt"
+	"io"
 	"io/ioutil"
+	"os"
 
 	"github.com/mitchellh/multistep"
 	"github.com/mitchellh/packer/packer"
@@ -47,7 +50,35 @@ func (b *Builder) Prepare(raws ...interface{}) ([]string, error) {
 func (b *Builder) Run(ui packer.Ui, hook packer.Hook, cache packer.Cache) (packer.Artifact, error) {
 	artifact := new(FileArtifact)
 
-	ioutil.WriteFile(b.config.Filename, []byte(b.config.Contents), 0600)
+	if b.config.Source != "" {
+		source, err := os.Open(b.config.Source)
+		defer source.Close()
+		if err != nil {
+			return nil, err
+		}
+
+		target, err := os.OpenFile(b.config.Target, os.O_WRONLY, 0600)
+		defer target.Close()
+		if err != nil {
+			return nil, err
+		}
+
+		ui.Say(fmt.Sprintf("Copying %s to %s", source.Name(), target.Name()))
+		bytes, err := io.Copy(source, target)
+		if err != nil {
+			return nil, err
+		}
+		ui.Say(fmt.Sprintf("Copied %d bytes", bytes))
+		artifact.filename = target.Name()
+	} else {
+		// We're going to write Contents; if it's empty we'll just create an
+		// empty file.
+		err := ioutil.WriteFile(b.config.Target, []byte(b.config.Content), 0600)
+		if err != nil {
+			return nil, err
+		}
+		artifact.filename = b.config.Target
+	}
 
 	return artifact, nil
 }

builder/file/config.go

@@ -9,11 +9,15 @@ import (
 	"github.com/mitchellh/packer/template/interpolate"
 )
 
+var ErrTargetRequired = fmt.Errorf("target required")
+var ErrContentSourceConflict = fmt.Errorf("Cannot specify source file AND content")
+
 type Config struct {
 	common.PackerConfig `mapstructure:",squash"`
 
-	Filename string `mapstructure:"filename"`
-	Contents string `mapstructure:"contents"`
+	Source  string `mapstructure:"source"`
+	Target  string `mapstructure:"target"`
+	Content string `mapstructure:"content"`
 }
 
 func NewConfig(raws ...interface{}) (*Config, []string, error) {
@@ -32,12 +36,16 @@ func NewConfig(raws ...interface{}) (*Config, []string, error) {
 
 	var errs *packer.MultiError
 
-	if c.Filename == "" {
-		errs = packer.MultiErrorAppend(errs, fmt.Errorf("filename is required"))
+	if c.Target == "" {
+		errs = packer.MultiErrorAppend(errs, ErrTargetRequired)
 	}
 
-	if c.Contents == "" {
-		warnings = append(warnings, "contents is empty")
+	if c.Content == "" && c.Source == "" {
+		warnings = append(warnings, "Both source file and contents are blank; target will have no content")
+	}
+
+	if c.Content != "" && c.Source != "" {
+		errs = packer.MultiErrorAppend(errs, ErrContentSourceConflict)
 	}
 
 	if errs != nil && len(errs.Errors) > 0 {

builder/file/config_test.go

@@ -2,13 +2,24 @@ package file
 
 import (
 	"fmt"
+	"strings"
 	"testing"
 )
 
 func testConfig() map[string]interface{} {
 	return map[string]interface{}{
-		"filename": "test.txt",
-		"contents": "Hello, world!",
+		"source":  "src.txt",
+		"target":  "dst.txt",
+		"content": "Hello, world!",
+	}
+}
+
+func TestContentSourceConflict(t *testing.T) {
+	raw := testConfig()
+
+	_, _, errs := NewConfig(raw)
+	if !strings.Contains(errs.Error(), ErrContentSourceConflict.Error()) {
+		t.Errorf("Expected config error: %s", ErrContentSourceConflict.Error())
 	}
 }
 
@@ -18,18 +29,19 @@ func TestNoFilename(t *testing.T) {
 	delete(raw, "filename")
 	_, _, errs := NewConfig(raw)
 	if errs == nil {
-		t.Error("Expected config to error without a filename")
+		t.Errorf("Expected config error: %s", ErrTargetRequired.Error())
 	}
 }
 
 func TestNoContent(t *testing.T) {
 	raw := testConfig()
 
-	delete(raw, "contents")
+	delete(raw, "content")
+	delete(raw, "source")
 	_, warns, _ := NewConfig(raw)
 	fmt.Println(len(warns))
 	fmt.Printf("%#v\n", warns)
 	if len(warns) == 0 {
-		t.Error("Expected config to warn without any content")
+		t.Error("Expected config warning without any content")
 	}
 }