Hi All,
the following code makes RPyC 3.3.0 crash on my machine because of too
early reference counting decrease.
Please note the following conditions:
- Synchronous client call that passes a callback function to the server.
- Asynchronous callback (event) that calls the received callback function.
- The event passes an object back to the client whose class definition is
unknown on the client side.
After debugging the code and tracing the protocol, it seems that the
callback function is requested to be deleted from the local objects
dictionary on the client side,
before the callback on this function is actually executed. And the callback
call is actually delayed because the parameter class definition is unknown
on the client side.
Unfortunately, I haven't figured out where to fix the error.
I would assume that the delete request needs to be delayed until the
callback finished. Note that the callback is asynchronous.
Thanks for any help,
Rico
Server code:
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
import rpyc
import os
class URL (str):
pass
class DownloadService (rpyc.Service):
def exposed_download_url (self, url, finished):
a = rpyc.async(finished)
a(URL(url))
if __name__ == '__main__':
print os.getpid()
from rpyc.utils.server import ThreadedServer
serv = ThreadedServer(DownloadService, port=18812,
protocol_config={"allow_all_attrs": True})
serv.start()
Client code:
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
import logging
import rpyc
def finished (self, url):
print "Finished."
if __name__ == '__main__':
url = "http://www.car-it.com/wp-content/uploads/2014/02/13C1150_092.jpg";
logging.basicConfig(level=logging.DEBUG)
log = logging.getLogger(__name__)
con = rpyc.connect("localhost", port=18812, config={"allow_all_attrs":
True, "logger": log})
con.root.download_url(url, finished)
# Keep alive.
while True:
pass
Client side exception:
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
pydev debugger: starting (pid: 1988)
DEBUG:__main__:Exception caught
Traceback (most recent call last):
File "C:\Program Files
(x86)\Python27\lib\site-packages\rpyc\core\protocol.py", line 305, in
_dispatch_request
res = self._HANDLERS[handler](self, *args)
File "C:\Program Files
(x86)\Python27\lib\site-packages\rpyc\core\protocol.py", line 535, in
_handle_call
return self._local_objects[oid](*args, **dict(kwargs))
File "C:\Program Files
(x86)\Python27\lib\site-packages\rpyc\lib\colls.py", line 86, in __getitem__
return self._dict[key][0]
KeyError: 40805104
Protocol trace (seq, msg):
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Client:
Server:
-------
-------
--> REQ
(0, 1): GetRoot()
(0, 2): (41243912, 'DownloadService', 'pkgs.dlserv') <-- RESP
--> REQ
(1, 1): Inspect(41243912)
(1, 2): <List of methods>
<-- RESP
--> REQ
(2, 1): GetAttr(41243912, 'download_url')
(2, 2): (38883696, 'instancemethod', '__builtin__') <-- RESP
--> REQ
(3, 1): Call(38883696, url, finished=(40805104, 'function',
'__builtin__'))
(0, 1): Call(40805104, url=(41284640, 'URL', '__main__')) <-- REQ
(3, 2): None
<-- RESP
(1, 1): Del(40805104)
<-- REQ
--> REQ
(4, 1): Inspect(41284640)
(4, 2): <Class description>
<-- RESP
--> RESP
(1, 2): None
--> EXCP
(0, 3): KeyError(40805104)
--
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![http://www.car-it.com/wp-content/uploads/2014/02/13C1150_092.jpg"](http://www.car-it.com/wp-content/uploads/2014/02/13C1150_092.jpg"){kind=link}