openstack
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oslo.messaging
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Document how call() handles remote exceptions 

This is tricky stuff, so document it carefuly.

Related-Bug: #1162063
Change-Id: Id197bf87e9a7ed222508efe5d5246003ac02680e
This commit is contained in:
Mark McLoughlin 2013-08-07 13:21:09 +01:00
parent ac2176cde3
commit bf171ede28
1 changed files with 18 additions and 0 deletions
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18
oslo/messaging/rpc/client.py
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@ -350,6 +350,24 @@ class RPCClient(object):
Method arguments must either be primitive types or types supported by
the client's serializer (if any).
The semantics of how any errors raised by the remote RPC endpoint
method are handled are quite subtle.
Firstly, if the remote exception is contained in one of the modules
listed in the allow_remote_exmods messaging.get_transport() parameter,
then it this exception will be re-raised by call(). However, such
locally re-raised remote exceptions are distinguishable from the same
exception type raised locally becayse re-raised remote exceptions are
modified such that their class name ends with the '_Remote' suffix so
you may do::
if ex.__class__.__name__.endswith('_Remote'):
# Some special case for locally re-raised remote exceptions
Secondly, if a remote exception is not from a module listed in the
allowed_remote_exmods list, then a messaging.RemoteError exception is
raised with all details of the remote exception.
:param ctxt: a request context dict
:type ctxt: dict
:param method: the method name