Merge pull request #511 from dotcloud/builder-cache

+ Builder: Add caching to docker builder

builder.go

@@ -165,6 +165,35 @@ func (builder *Builder) clearTmp(containers, images map[string]struct{}) {
 	}
 }
 
+func (builder *Builder) getCachedImage(image *Image, config *Config) (*Image, error) {
+	// Retrieve all images
+	images, err := builder.graph.All()
+	if err != nil {
+		return nil, err
+	}
+
+	// Store the tree in a map of map (map[parentId][childId])
+	imageMap := make(map[string]map[string]struct{})
+	for _, img := range images {
+		if _, exists := imageMap[img.Parent]; !exists {
+			imageMap[img.Parent] = make(map[string]struct{})
+		}
+		imageMap[img.Parent][img.Id] = struct{}{}
+	}
+
+	// Loop on the children of the given image and check the config
+	for elem := range imageMap[image.Id] {
+		img, err := builder.graph.Get(elem)
+		if err != nil {
+			return nil, err
+		}
+		if CompareConfig(&img.ContainerConfig, config) {
+			return img, nil
+		}
+	}
+	return nil, nil
+}
+
 func (builder *Builder) Build(dockerfile io.Reader, stdout io.Writer) (*Image, error) {
 	var (
 		image, base   *Image
@@ -183,7 +212,7 @@ func (builder *Builder) Build(dockerfile io.Reader, stdout io.Writer) (*Image, e
 			}
 			return nil, err
 		}
-		line = strings.TrimSpace(line)
+		line = strings.Replace(strings.TrimSpace(line), "	", " ", 1)
 		// Skip comments and empty line
 		if len(line) == 0 || line[0] == '#' {
 			continue
@@ -202,10 +231,12 @@ func (builder *Builder) Build(dockerfile io.Reader, stdout io.Writer) (*Image, e
 				if builder.runtime.graph.IsNotExist(err) {
 
 					var tag, remote string
-					if strings.Contains(remote, ":") {
-						remoteParts := strings.Split(remote, ":")
+					if strings.Contains(arguments, ":") {
+						remoteParts := strings.Split(arguments, ":")
 						tag = remoteParts[1]
 						remote = remoteParts[0]
+					} else {
+						remote = arguments
 					}
 
 					if err := builder.runtime.graph.PullRepository(stdout, remote, tag, builder.runtime.repositories, builder.runtime.authConfig); err != nil {
@@ -216,7 +247,6 @@ func (builder *Builder) Build(dockerfile io.Reader, stdout io.Writer) (*Image, e
 					if err != nil {
 						return nil, err
 					}
-
 				} else {
 					return nil, err
 				}
@@ -237,6 +267,14 @@ func (builder *Builder) Build(dockerfile io.Reader, stdout io.Writer) (*Image, e
 				return nil, err
 			}
 
+			if cache, err := builder.getCachedImage(image, config); err != nil {
+				return nil, err
+			} else if cache != nil {
+				image = cache
+				fmt.Fprintf(stdout, "===> %s\n", image.ShortId())
+				break
+			}
+
 			// Create the container and start it
 			c, err := builder.Create(config)
 			if err != nil {
@@ -344,10 +382,10 @@ func (builder *Builder) Build(dockerfile io.Reader, stdout io.Writer) (*Image, e
 
 			break
 		default:
-			fmt.Fprintf(stdout, "Skipping unknown instruction %s\n", instruction)
+			fmt.Fprintf(stdout, "Skipping unknown instruction %s\n", strings.ToUpper(instruction))
 		}
 	}
-	if base != nil {
+	if image != nil {
 		// The build is successful, keep the temporary containers and images
 		for i := range tmpImages {
 			delete(tmpImages, i)
@@ -355,9 +393,8 @@ func (builder *Builder) Build(dockerfile io.Reader, stdout io.Writer) (*Image, e
 		for i := range tmpContainers {
 			delete(tmpContainers, i)
 		}
-		fmt.Fprintf(stdout, "Build finished. image id: %s\n", base.ShortId())
-	} else {
-		fmt.Fprintf(stdout, "An error occured during the build\n")
+		fmt.Fprintf(stdout, "Build finished. image id: %s\n", image.ShortId())
+		return image, nil
 	}
-	return base, nil
+	return nil, fmt.Errorf("An error occured during the build\n")
 }

utils.go

@@ -474,3 +474,50 @@ func FindCgroupMountpoint(cgroupType string) (string, error) {
 
 	return "", fmt.Errorf("cgroup mountpoint not found for %s", cgroupType)
 }
+
+// Compare two Config struct. Do not compare the "Image" nor "Hostname" fields
+// If OpenStdin is set, then it differs
+func CompareConfig(a, b *Config) bool {
+	if a == nil || b == nil ||
+		a.OpenStdin || b.OpenStdin {
+		return false
+	}
+	if a.AttachStdout != b.AttachStdout ||
+		a.AttachStderr != b.AttachStderr ||
+		a.User != b.User ||
+		a.Memory != b.Memory ||
+		a.MemorySwap != b.MemorySwap ||
+		a.OpenStdin != b.OpenStdin ||
+		a.Tty != b.Tty {
+		return false
+	}
+	if len(a.Cmd) != len(b.Cmd) ||
+		len(a.Dns) != len(b.Dns) ||
+		len(a.Env) != len(b.Env) ||
+		len(a.PortSpecs) != len(b.PortSpecs) {
+		return false
+	}
+
+	for i := 0; i < len(a.Cmd); i++ {
+		if a.Cmd[i] != b.Cmd[i] {
+			return false
+		}
+	}
+	for i := 0; i < len(a.Dns); i++ {
+		if a.Dns[i] != b.Dns[i] {
+			return false
+		}
+	}
+	for i := 0; i < len(a.Env); i++ {
+		if a.Env[i] != b.Env[i] {
+			return false
+		}
+	}
+	for i := 0; i < len(a.PortSpecs); i++ {
+		if a.PortSpecs[i] != b.PortSpecs[i] {
+			return false
+		}
+	}
+
+	return true
+}