fix(controller): build image from source_tag

'sha' is just metadata. it is not used as a tag on the registry.

The release ledger is append-only, which means that the latest image should be
used by default, with an optional source tag for rollbacks.

Author: Matthew Fisher

controller/api/models.py

@@ -462,7 +462,7 @@ class Meta:
     def __str__(self):
         return "{0}-v{1}".format(self.app.id, self.version)
 
-    def new(self, user, config=None, build=None, summary=None):
+    def new(self, user, config=None, build=None, summary=None, source_version='latest'):
         """
         Create a new application release using the provided Build and Config
         on behalf of a user.
@@ -473,11 +473,8 @@ def new(self, user, config=None, build=None, summary=None):
             config = self.config
         if not build:
             build = self.build
-        # construct fully-qualified build image
-        if build.sha:
-            source_image = '{}:{}'.format(build.image, build.sha)
-        else:
-            source_image = '{}:{}'.format(build.image, 'latest')
+        # always create a release off the latest image
+        source_image = '{}:{}'.format(build.image, source_version)
         # construct fully-qualified target image
         new_version = self.version + 1
         tag = 'v{}'.format(new_version)

controller/api/views.py

@@ -427,7 +427,8 @@ def rollback(self, request, *args, **kwargs):
             request.user,
             build=prev.build,
             config=prev.config,
-            summary=summary)
+            summary=summary,
+            source_version='v{}'.format(version))
         app.deploy(new_release)
         response = {'version': new_release.version}
         return Response(response, status=status.HTTP_201_CREATED)