Make API errors more informative

Fixes https://jira.coreos.com/browse/QUAY-999

endpoints/decorators.py

@@ -32,7 +32,7 @@ def parse_repository_name(include_tag=False,
                                                           include_tag=include_tag,
                                                           allow_library=features.LIBRARY_SUPPORT)
       except ImplicitLibraryNamespaceNotAllowed:
-        abort(400)
+        abort(400, message='A namespace must be specified explicitly')
 
       del kwargs[incoming_repo_kwarg]
       kwargs[ns_kwarg_name] = repo_name_components[0]
@@ -54,7 +54,7 @@ def param_required(param_name, allow_body=False):
     def decorated(*args, **kwargs):
       if param_name not in request.args:
         if not allow_body or param_name not in request.values:
-          abort(make_response('Required param: %s' % param_name, 400))
+          abort(400, message='Required param: %s' % param_name)
       return wrapped(*args, **kwargs)
     return decorated
   return wrapper
@@ -85,7 +85,7 @@ def check_anon_protection(func):
     if get_authenticated_context() and not get_authenticated_context().is_anonymous:
       return func(*args, **kwargs)
 
-    abort(401)
+    abort(401, message='Anonymous access is not allowed')
 
   return wrapper
 
@@ -117,7 +117,8 @@ def require_xhr_from_browser(func):
         if not has_xhr_header and not app.config.get('DEBUGGING') == True:
           logger.warning('Disallowed possible RTA to URL %s with user agent %s',
                          request.path, request.user_agent)
-          abort(400)
+          abort(400, message='API calls must be invoked with an X-Requested-With header ' +
+                'if called from a browser')
 
     return func(*args, **kwargs)
   return wrapper

util/http.py

@@ -19,7 +19,7 @@ DEFAULT_MESSAGE[409] = 'Conflict'
 DEFAULT_MESSAGE[501] = 'Not Implemented'
 
 
-def _abort(status_code, data_object, headers):
+def _abort(status_code, data_object, description, headers):
   # Add CORS headers to all errors
   options_resp = current_app.make_default_options_response()
   headers['Access-Control-Allow-Origin'] = '*'
@@ -31,7 +31,7 @@ def _abort(status_code, data_object, headers):
 
   # Report the abort to the user.
   # Raising HTTPException as workaround for https://github.com/pallets/werkzeug/issues/1098
-  new_exception = HTTPException(response=resp)
+  new_exception = HTTPException(response=resp, description=description)
   new_exception.code = status_code
   raise new_exception
 
@@ -42,11 +42,10 @@ def exact_abort(status_code, message=None):
   if message is not None:
     data['error'] = message
 
-  _abort(status_code, data, {})
+  _abort(status_code, data, message or None, {})
 
 
 def abort(status_code, message=None, issue=None, headers=None, **kwargs):
-
   message = (str(message) % kwargs if message else
              DEFAULT_MESSAGE.get(status_code, ''))
 
@@ -80,4 +79,4 @@ def abort(status_code, message=None, issue=None, headers=None, **kwargs):
   if headers is None:
     headers = {}
 
-  _abort(status_code, data, headers)
+  _abort(status_code, data, message, headers)