Common exception base class: CeleryException/CeleryWarning. Closes #2643

celery/exceptions.py

@@ -16,22 +16,33 @@ from billiard.exceptions import (  # noqa
     SoftTimeLimitExceeded, TimeLimitExceeded, WorkerLostError, Terminated,
 )
 
-__all__ = ['SecurityError', 'Ignore', 'QueueNotFound',
-           'WorkerShutdown', 'WorkerTerminate',
-           'ImproperlyConfigured', 'NotRegistered', 'AlreadyRegistered',
-           'TimeoutError', 'MaxRetriesExceededError', 'Retry',
-           'TaskRevokedError', 'NotConfigured', 'AlwaysEagerIgnored',
-           'InvalidTaskError', 'ChordError', 'CPendingDeprecationWarning',
-           'CDeprecationWarning', 'FixupWarning', 'DuplicateNodenameWarning',
-           'SoftTimeLimitExceeded', 'TimeLimitExceeded', 'WorkerLostError',
-           'Terminated']
+__all__ = [
+    'CeleryError', 'CeleryWarning', 'TaskPredicate',
+    'SecurityError', 'Ignore', 'QueueNotFound',
+    'WorkerShutdown', 'WorkerTerminate',
+    'ImproperlyConfigured', 'NotRegistered', 'AlreadyRegistered',
+    'TimeoutError', 'MaxRetriesExceededError', 'Retry',
+    'TaskRevokedError', 'NotConfigured', 'AlwaysEagerIgnored',
+    'InvalidTaskError', 'ChordError', 'CPendingDeprecationWarning',
+    'CDeprecationWarning', 'FixupWarning', 'DuplicateNodenameWarning',
+    'SoftTimeLimitExceeded', 'TimeLimitExceeded', 'WorkerLostError',
+    'Terminated',
+]
 
 UNREGISTERED_FMT = """\
 Task of kind {0} is not registered, please make sure it's imported.\
 """
 
 
-class SecurityError(Exception):
+class CeleryError(Exception):
+    pass
+
+
+class CeleryWarning(UserWarning):
+    pass
+
+
+class SecurityError(CeleryError):
     """Security related exceptions.
 
     Handle with care.
@@ -39,11 +50,55 @@ class SecurityError(Exception):
     """
 
 
-class Ignore(Exception):
+class TaskPredicate(CeleryError):
+    pass
+
+
+class Retry(TaskPredicate):
+    """The task is to be retried later."""
+
+    #: Optional message describing context of retry.
+    message = None
+
+    #: Exception (if any) that caused the retry to happen.
+    exc = None
+
+    #: Time of retry (ETA), either :class:`numbers.Real` or
+    #: :class:`~datetime.datetime`.
+    when = None
+
+    def __init__(self, message=None, exc=None, when=None, **kwargs):
+        from kombu.utils.encoding import safe_repr
+        self.message = message
+        if isinstance(exc, string_t):
+            self.exc, self.excs = None, exc
+        else:
+            self.exc, self.excs = exc, safe_repr(exc) if exc else None
+        self.when = when
+        Exception.__init__(self, exc, when, **kwargs)
+
+    def humanize(self):
+        if isinstance(self.when, numbers.Real):
+            return 'in {0.when}s'.format(self)
+        return 'at {0.when}'.format(self)
+
+    def __str__(self):
+        if self.message:
+            return self.message
+        if self.excs:
+            return 'Retry {0}: {1}'.format(self.humanize(), self.excs)
+        return 'Retry {0}'.format(self.humanize())
+
+    def __reduce__(self):
+        return self.__class__, (self.message, self.excs, self.when)
+RetryTaskError = Retry   # XXX compat
+
+
+class Ignore(TaskPredicate):
     """A task can raise this to ignore doing state updates."""
 
 
-class Reject(Exception):
+class Reject(TaskPredicate):
     """A task can raise this if it wants to reject/requeue the message."""
 
     def __init__(self, reason=None, requeue=False):
@@ -72,86 +127,46 @@ class ImproperlyConfigured(ImportError):
     """Celery is somehow improperly configured."""
 
 
-class NotRegistered(KeyError):
+class NotRegistered(KeyError, CeleryError):
     """The task is not registered."""
 
     def __repr__(self):
         return UNREGISTERED_FMT.format(self)
 
 
-class AlreadyRegistered(Exception):
+class AlreadyRegistered(CeleryError):
     """The task is already registered."""
 
 
-class TimeoutError(Exception):
+class TimeoutError(CeleryError):
     """The operation timed out."""
 
 
-class MaxRetriesExceededError(Exception):
+class MaxRetriesExceededError(CeleryError):
     """The tasks max restart limit has been exceeded."""
 
 
-class Retry(Exception):
-    """The task is to be retried later."""
-
-    #: Optional message describing context of retry.
-    message = None
-
-    #: Exception (if any) that caused the retry to happen.
-    exc = None
-
-    #: Time of retry (ETA), either :class:`numbers.Real` or
-    #: :class:`~datetime.datetime`.
-    when = None
-
-    def __init__(self, message=None, exc=None, when=None, **kwargs):
-        from kombu.utils.encoding import safe_repr
-        self.message = message
-        if isinstance(exc, string_t):
-            self.exc, self.excs = None, exc
-        else:
-            self.exc, self.excs = exc, safe_repr(exc) if exc else None
-        self.when = when
-        Exception.__init__(self, exc, when, **kwargs)
-
-    def humanize(self):
-        if isinstance(self.when, numbers.Real):
-            return 'in {0.when}s'.format(self)
-        return 'at {0.when}'.format(self)
-
-    def __str__(self):
-        if self.message:
-            return self.message
-        if self.excs:
-            return 'Retry {0}: {1}'.format(self.humanize(), self.excs)
-        return 'Retry {0}'.format(self.humanize())
-
-    def __reduce__(self):
-        return self.__class__, (self.message, self.excs, self.when)
-RetryTaskError = Retry   # XXX compat
-
-
-class TaskRevokedError(Exception):
+class TaskRevokedError(CeleryError):
     """The task has been revoked, so no result available."""
 
 
-class NotConfigured(UserWarning):
+class NotConfigured(CeleryWarning):
     """Celery has not been configured, as no config module has been found."""
 
 
-class AlwaysEagerIgnored(UserWarning):
+class AlwaysEagerIgnored(CeleryWarning):
     """send_task ignores CELERY_ALWAYS_EAGER option"""
 
 
-class InvalidTaskError(Exception):
+class InvalidTaskError(CeleryError):
     """The task has invalid data or is not properly constructed."""
 
 
-class IncompleteStream(Exception):
+class IncompleteStream(CeleryError):
     """Found the end of a stream of data, but the data is not yet complete."""
 
 
-class ChordError(Exception):
+class ChordError(CeleryError):
     """A task part of the chord raised an exception."""
 
 
@@ -163,9 +178,9 @@ class CDeprecationWarning(DeprecationWarning):
     pass
 
 
-class FixupWarning(UserWarning):
+class FixupWarning(CeleryWarning):
     pass
 
 
-class DuplicateNodenameWarning(UserWarning):
+class DuplicateNodenameWarning(CeleryWarning):
     """Multiple workers are using the same nodename."""