Stephan Popp Stephan.Popp@iisb.fraunhofer.de writes:
If the pythonscript named taskDescription.fileName isn't there self.serverErrorCB is called - thats ok. But it prints: reason [Failure instance: Traceback from remote host -- Traceback unavailable]
But I need to know why the call failed. Can anyone please help me to get the traceback or the exception message that the server prints (exceptions.ImportError: No module named fitfunc2).
The returned Failure instance should still encapsulate the underlying exception information in the type and value fields, as is usual with Failure objects. One difference from a local Failure instance though is that type will be a string representation of the exception class and not the class object itself in the PB client context. If you stick with failure.trap() and failure.check() for explicit exception checks in errback chains, they handle both the direct class as well as string version, so errback code will work locally or via a PB client.
So you can still identify the root exception (ImportError). It just happens to not show up in the default __str__ output for the failure object (e.g., your print in your errback) but if you were to modify that print to explicitly print out the type and value fields, and not just let the failure object generate its own printable format, you can see the information. And checking for an exception itself rather than looking for textual information in a traceback is probably better for production code.
If you really want to see the traceback during development/debugging, you should see them output as a log message on the server side (if you have twisted logging going somewhere). Alternatively, I believe you can enable "unsafe" tracebacks (which sends the traceback to remote clients) by setting the unsafeTracebacks attribute in the factory on the side on which the exception is being generated - the PBServerFactory side in your case. For PBServerFactory, it's an optional argument to the constructor.