python-novaclient/novaclient/exceptions.py

# Copyright 2010 Jacob Kaplan-Moss
"""
Exception definitions.
"""


class UnsupportedVersion(Exception):
    """Indicates that the user is trying to use an unsupported
    version of the API"""
    pass


class CommandError(Exception):
    pass


class AuthorizationFailure(Exception):
    pass


class NoUniqueMatch(Exception):
    pass


class AuthSystemNotFound(Exception):
    """When the user specify a AuthSystem but not installed."""
    def __init__(self, auth_system):
        self.auth_system = auth_system

    def __str__(self):
        return "AuthSystemNotFound: %s" % repr(self.auth_system)


class NoTokenLookupException(Exception):
    """This form of authentication does not support looking up
       endpoints from an existing token."""
    pass


class EndpointNotFound(Exception):
    """Could not find Service or Region in Service Catalog."""
    pass


class AmbiguousEndpoints(Exception):
    """Found more than one matching endpoint in Service Catalog."""
    def __init__(self, endpoints=None):
        self.endpoints = endpoints

    def __str__(self):
        return "AmbiguousEndpoints: %s" % repr(self.endpoints)


class ConnectionRefused(Exception):
    """
    Connection refused: the server refused the connection.
    """
    def __init__(self, response=None):
        self.response = response

    def __str__(self):
        return "ConnectionRefused: %s" % repr(self.response)


class ClientException(Exception):
    """
    The base exception class for all exceptions this library raises.
    """
    def __init__(self, code, message=None, details=None, request_id=None,
                 url=None, method=None):
        self.code = code
        self.message = message or self.__class__.message
        self.details = details
        self.request_id = request_id
        self.url = url
        self.method = method

    def __str__(self):
        formatted_string = "%s (HTTP %s)" % (self.message, self.code)
        if self.request_id:
            formatted_string += " (Request-ID: %s)" % self.request_id

        return formatted_string


class BadRequest(ClientException):
    """
    HTTP 400 - Bad request: you sent some malformed data.
    """
    http_status = 400
    message = "Bad request"


class Unauthorized(ClientException):
    """
    HTTP 401 - Unauthorized: bad credentials.
    """
    http_status = 401
    message = "Unauthorized"


class Forbidden(ClientException):
    """
    HTTP 403 - Forbidden: your credentials don't give you access to this
    resource.
    """
    http_status = 403
    message = "Forbidden"


class NotFound(ClientException):
    """
    HTTP 404 - Not found
    """
    http_status = 404
    message = "Not found"


class MethodNotAllowed(ClientException):
    """
    HTTP 405 - Method Not Allowed
    """
    http_status = 405
    message = "Method Not Allowed"


class Conflict(ClientException):
    """
    HTTP 409 - Conflict
    """
    http_status = 409
    message = "Conflict"


class OverLimit(ClientException):
    """
    HTTP 413 - Over limit: you're over the API limits for this time period.
    """
    http_status = 413
    message = "Over limit"

    def __init__(self, *args, **kwargs):
        try:
            self.retry_after = int(kwargs.pop('retry_after'))
        except (KeyError, ValueError):
            self.retry_after = 0

        super(OverLimit, self).__init__(*args, **kwargs)


class RateLimit(OverLimit):
    """
    HTTP 429 - Rate limit: you've sent too many requests for this time period.
    """
    http_status = 429
    message = "Rate limit"


# NotImplemented is a python keyword.
class HTTPNotImplemented(ClientException):
    """
    HTTP 501 - Not Implemented: the server does not support this operation.
    """
    http_status = 501
    message = "Not Implemented"


# In Python 2.4 Exception is old-style and thus doesn't have a __subclasses__()
# so we can do this:
#     _code_map = dict((c.http_status, c)
#                      for c in ClientException.__subclasses__())
#
# Instead, we have to hardcode it:
_error_classes = [BadRequest, Unauthorized, Forbidden, NotFound,
                  MethodNotAllowed, Conflict, OverLimit, RateLimit,
                  HTTPNotImplemented]
_code_map = dict((c.http_status, c) for c in _error_classes)


def from_response(response, body, url, method=None):
    """
    Return an instance of an ClientException or subclass
    based on an requests response.

    Usage::

        resp, body = requests.request(...)
        if resp.status_code != 200:
            raise exception_from_response(resp, rest.text)
    """
    kwargs = {
        'code': response.status_code,
        'method': method,
        'url': url,
        'request_id': None,
    }

    if response.headers:
        kwargs['request_id'] = response.headers.get('x-compute-request-id')

        if 'retry-after' in response.headers:
            kwargs['retry_after'] = response.headers.get('retry-after')

    if body:
        message = "n/a"
        details = "n/a"

        if hasattr(body, 'keys'):
            error = body[body.keys()[0]]
            message = error.get('message', None)
            details = error.get('details', None)

        kwargs['message'] = message
        kwargs['details'] = details

    cls = _code_map.get(response.status_code, ClientException)
    return cls(**kwargs)