Added basic exception parsing for interaction w/ drivers

senlin/common/sdk.py

@@ -13,13 +13,157 @@
 '''
 SDK Client
 '''
+
+from oslo_serialization import jsonutils
+
 from openstack import connection
 from openstack import exceptions
 from openstack import user_preference
+from requests import exceptions as reqexc
 
 USER_AGENT = 'senlin'
 
 exc = exceptions
+verbose = False
+
+
+class BaseException(Exception):
+    '''An error occurred.'''
+    def __init__(self, message=None):
+        self.message = message
+
+    def __str__(self):
+        return self.message or self.__class__.__doc__
+
+
+class HTTPException(BaseException):
+    """Base exception for all HTTP-derived exceptions."""
+    code = 'N/A'
+
+    def __init__(self, error=None):
+        super(HTTPException, self).__init__(error)
+        try:
+            self.error = error
+            if 'error' not in self.error:
+                raise KeyError(_('Key "error" not exists'))
+        except KeyError:
+            # If key 'error' does not exist, self.message becomes
+            # no sense. In this case, we return doc of current
+            # exception class instead.
+            self.error = {'error': {'message': self.__class__.__doc__}}
+        except Exception:
+            self.error = {'error':
+                          {'message': self.message or self.__class__.__doc__}}
+
+    def __str__(self):
+        message = self.error['error'].get('message', 'Internal Error')
+        if verbose:
+            traceback = self.error['error'].get('traceback', '')
+            return (_('ERROR: %(message)s\n%(traceback)s') %
+                    {'message': message, 'traceback': traceback})
+        else:
+            code = self.error['error'].get('code', 'Unknown')
+            return _('ERROR(%(code)s): %(message)s') % {'code': code,
+                                                        'message': message}
+
+
+class ClientError(HTTPException):
+    pass
+
+
+class ServerError(HTTPException):
+    pass
+
+
+class ConnectionRefused(HTTPException):
+    # 111
+    pass
+
+
+class HTTPBadRequest(ClientError):
+    # 400
+    pass
+
+
+class HTTPUnauthorized(ClientError):
+    # 401
+    pass
+
+
+class HTTPForbidden(ClientError):
+    # 403
+    pass
+
+
+class HTTPNotFound(ClientError):
+    # 404
+    pass
+
+
+class HTTPInternalServerError(ServerError):
+    # 500
+    pass
+
+
+class HTTPNotImplemented(ServerError):
+    # 501
+    pass
+
+
+class HTTPServiceUnavailable(ServerError):
+    # 503
+    pass
+
+
+_EXCEPTION_MAP = {
+    111: ConnectionRefused,
+    400: HTTPBadRequest,
+    401: HTTPUnauthorized,
+    403: HTTPForbidden,
+    404: HTTPNotFound,
+    500: HTTPInternalServerError,
+    501: HTTPNotImplemented,
+    503: HTTPServiceUnavailable,
+}
+
+
+def parse_exception(ex):
+    '''Parse exception code and yield useful information.
+    :param details: details of the exception.
+    '''
+    if isinstance(ex, exc.HttpException):
+        record = jsonutils.loads(ex.details)
+    elif isinstance(ex, reqexc.RequestException):
+        # Exceptions that are not captured by SDK
+        code = ex.message[1].errno
+        record = {
+            'error': {
+                'code': code,
+                'message': ex.message[0],
+            }
+        }
+    else:
+        print(_('Unknown exception: %s') % ex)
+        return
+
+    try:
+        code = record['error']['code']
+    except KeyError as err:
+        print(_('Malformed exception record, missing field "%s"') % err)
+        print(_('Original error record: %s') % record)
+        return
+
+    if code in _EXCEPTION_MAP:
+        inst = _EXCEPTION_MAP.get(code)
+        return inst(record)
+    else:
+        return HTTPException(record)
+
+
+def ignore_not_found(ex):
+    parsed = parse_exception(ex)
+    if not isinstance(parsed, HTTPNotFound):
+        raise parsed
 
 
 def create_connection(context):