Fix issues in GCEImageService.

cloudbridge/cloud/providers/gce/services.py

@@ -275,12 +275,14 @@ class GCEImageService(BaseImageService):
         super(GCEImageService, self).__init__(provider)
         self._public_images = None
 
-    PUBLIC_IMAGE_PROJECTS = ['centos-cloud', 'coreos-cloud', 'debian-cloud',
+    _PUBLIC_IMAGE_PROJECTS = ['centos-cloud', 'coreos-cloud', 'debian-cloud',
                              'opensuse-cloud', 'ubuntu-os-cloud']
 
     def _retrieve_public_images(self):
+        if self._public_images is not None:
+            return
         self._public_images = []
-        for project in GCEImageService.PUBLIC_IMAGE_PROJECTS:
+        for project in GCEImageService._PUBLIC_IMAGE_PROJECTS:
             try:
                 response = self.provider.gce_compute \
                                         .images() \
@@ -298,8 +300,7 @@ class GCEImageService(BaseImageService):
         """
         Returns an Image given its name
         """
-        if self._public_images == None:
-            self._retrieve_public_images()
+        self._retrieve_public_images()
         try:
             image = self.provider.gce_compute \
                                   .images() \
@@ -313,30 +314,35 @@ class GCEImageService(BaseImageService):
             # match the pattern "[a-z](?:[-a-z0-9]{0,61}[a-z0-9])?".
             print("TypeError: {0}".format(type_error))
         except googleapiclient.errors.HttpError as http_error:
+            # If the image is not found in project-specific private images,
+            # look for this image in public images.
+            for public_image in self._public_images:
+                if public_image.name == image_name:
+                    return public_image
             print("googleapiclient.errors.HttpError: {0}".format(http_error))
-        for public_image in self._public_images:
-            if public_image.name == image_name:
-                return public_image
         return None
 
     def find(self, name, limit=None, marker=None):
         """
         Searches for an image by a given list of attributes
         """
-        if self._public_images == None:
-            self._retrieve_public_images()
+        self._retrieve_public_images()
         filters = {'name': name}
         images = []
-        try:
-            response = self.provider.gce_compute \
-                                    .images() \
-                                  .list(project=self.provider.project_name) \
-                                  .execute()
-            if 'items' in response:
-                images = [GCEMachineImage(self.provider, image) for image
-                          in response['items']]
-        except googleapiclient.errors.HttpError as http_error:
-            print("googleapiclient.errors.HttpError: {0}".format(http_error))
+        if (self.provider.project_name not in
+            GCEImageService._PUBLIC_IMAGE_PROJECTS):
+            try:
+                response = self.provider \
+                               .gce_compute \
+                               .images() \
+                               .list(project=self.provider.project_name) \
+                               .execute()
+                if 'items' in response:
+                    images = [GCEMachineImage(self.provider, image) for image
+                              in response['items']]
+            except googleapiclient.errors.HttpError as http_error:
+                print(
+                    "googleapiclient.errors.HttpError: {0}".format(http_error))
         images.extend(self._public_images)
         images = [image for image in images if image.name == filters['name']]
         return ClientPagedResultList(self.provider, images,
@@ -346,19 +352,22 @@ class GCEImageService(BaseImageService):
         """
         List all images.
         """
-        if self._public_images == None:
-            self._retrieve_public_images()
+        self._retrieve_public_images()
         images = []
-        try:
-            response = self.provider.gce_compute \
-                                  .images() \
-                                  .list(project=self.provider.project_name) \
-                                  .execute()
-            if 'items' in response:
-                images = [GCEMachineImage(self.provider, image) for image
-                          in response['items']]
-        except googleapiclient.errors.HttpError as http_error:
-            print("googleapiclient.errors.HttpError: {0}".format(http_error))
+        if (self.provider.project_name not in
+            GCEImageService._PUBLIC_IMAGE_PROJECTS):
+            try:
+                response = self.provider \
+                               .gce_compute \
+                               .images() \
+                               .list(project=self.provider.project_name) \
+                               .execute()
+                if 'items' in response:
+                    images = [GCEMachineImage(self.provider, image) for image
+                              in response['items']]
+            except googleapiclient.errors.HttpError as http_error:
+                print(
+                    "googleapiclient.errors.HttpError: {0}".format(http_error))
         images.extend(self._public_images)
         return ClientPagedResultList(self.provider, images,
                                      limit=limit, marker=marker)