Handle empty GitHub repositories and do not 500 if the repository cannot be read

endpoints/api/trigger.py

@@ -13,7 +13,8 @@ from endpoints.api.build import (build_status_view, trigger_view, RepositoryBuil
                                  get_trigger_config)
 from endpoints.common import start_build
 from endpoints.trigger import (BuildTrigger as BuildTriggerBase, TriggerDeactivationException,
-                               TriggerActivationException, EmptyRepositoryException)
+                               TriggerActivationException, EmptyRepositoryException,
+                               RepositoryReadException)
 from data import model
 from auth.permissions import UserAdminPermission
 
@@ -116,9 +117,14 @@ class BuildTriggerSubdirs(RepositoryParamResource):
           'status': 'success'
         }
       except EmptyRepositoryException as exc:
+        return {
+          'status': 'success',
+          'subdir': []
+        }
+      except RepositoryReadException as exc:
         return {
           'status': 'error',
-          'message': exc.msg
+          'message': exc.message
         }
     else:
       raise Unauthorized()

endpoints/trigger.py

@@ -38,6 +38,9 @@ class ValidationRequestException(Exception):
 class EmptyRepositoryException(Exception):
   pass
 
+class RepositoryReadException(Exception):
+  pass
+
 
 class BuildTrigger(object):
   def __init__(self):
@@ -209,9 +212,12 @@ class GithubBuildTrigger(BuildTrigger):
       return [os.path.dirname(elem.path) for elem in commit_tree.tree
               if (elem.type == u'blob' and
                   os.path.basename(elem.path) == u'Dockerfile')]
-    except GithubException:
-      msg = 'Unable to list contents of repository: %s' % source
-      raise EmptyRepositoryException(msg)
+    except GithubException as ge:
+      message = ge.data.get('message', 'Unable to list contents of repository: %s' % source)
+      if message == 'Branch not found':
+        raise EmptyRepositoryException()
+
+      raise RepositoryReadException(message)
 
   @staticmethod
   def _prepare_build(config, repo, commit_sha, build_name, ref):