Merge remote-tracking branch 'dotcloud/master' into dhrp/docs

Conflicts:
	docs/sources/examples/python_web_app.rst

docs/sources/examples/python_web_app.rst

@@ -24,9 +24,9 @@ We set a URL variable that points to a tarball of a simple helloflask web app
 
 .. code-block:: bash
 
-    BUILD_JOB=$(docker run -t shykes/pybuilder:1d9aab3737242c65 /usr/local/bin/buildapp $URL)
+    BUILD_JOB=$(docker run -d -t shykes/pybuilder:latest /usr/local/bin/buildapp $URL)
 
-Inside of the "shykes/pybuilder" image there is a command called buildapp, we are running that command and passing the $URL variable from step 2 to it, and running the whole thing inside of a new container. BUILD_JOB will be set with the new container_id. "1d9aab3737242c65" came from the output of step 1 when importing image. also available from 'docker images'.
+Inside of the "shykes/pybuilder" image there is a command called buildapp, we are running that command and passing the $URL variable from step 2 to it, and running the whole thing inside of a new container. BUILD_JOB will be set with the new container_id.
 
 .. code-block:: bash
 
@@ -43,7 +43,7 @@ Save the changed we just made in the container to a new image called "_/builds/g
 
 .. code-block:: bash
 
-    WEB_WORKER=$(docker run -p 5000 $BUILD_IMG /usr/local/bin/runapp)
+    WEB_WORKER=$(docker run -d -p 5000 $BUILD_IMG /usr/local/bin/runapp)
 
 Use the new image we just created and create a new container with network port 5000, and return the container id and store in the WEB_WORKER variable.
 

graph.go

@@ -110,12 +110,44 @@ func (graph *Graph) Garbage() (*Graph, error) {
 	return NewGraph(path.Join(graph.Root, ":garbage:"))
 }
 
+// Check if given error is "not empty"
+// Note: this is the way golang do it internally with os.IsNotExists
+func isNotEmpty(err error) bool {
+	switch pe := err.(type) {
+	case nil:
+		return false
+	case *os.PathError:
+		err = pe.Err
+	case *os.LinkError:
+		err = pe.Err
+	}
+	return strings.Contains(err.Error(), " not empty")
+}
+
 func (graph *Graph) Delete(id string) error {
 	garbage, err := graph.Garbage()
 	if err != nil {
 		return err
 	}
-	return os.Rename(graph.imageRoot(id), garbage.imageRoot(id))
+	err = os.Rename(graph.imageRoot(id), garbage.imageRoot(id))
+	if err != nil {
+		if isNotEmpty(err) {
+			Debugf("The image %s is already present in garbage. Removing it.", id)
+			if err = os.RemoveAll(garbage.imageRoot(id)); err != nil {
+				Debugf("Error while removing the image %s from garbage: %s\n", id, err)
+				return err
+			}
+			Debugf("Image %s removed from garbage", id)
+			if err = os.Rename(graph.imageRoot(id), garbage.imageRoot(id)); err != nil {
+				return err
+			}
+			Debugf("Image %s put in the garbage", id)
+		} else {
+			Debugf("Error putting the image %s to garbage: %s\n", id, err)
+		}
+		return err
+	}
+	return nil
 }
 
 func (graph *Graph) Undelete(id string) error {

graph_test.go

@@ -158,6 +158,14 @@ func TestDelete(t *testing.T) {
 	}
 	assertNImages(graph, t, 1)
 
+	// Test delete twice (pull -> rm -> pull -> rm)
+	if err := graph.Register(archive, img1); err != nil {
+		t.Fatal(err)
+	}
+	if err := graph.Delete(img1.Id); err != nil {
+		t.Fatal(err)
+	}
+	assertNImages(graph, t, 1)
 }
 
 func assertNImages(graph *Graph, t *testing.T, n int) {