[infinispan-dev] HotRod exec operation tight coupling with JBoss Marshaller

[Galder Zamarreño]

Hi all,

While implement `exec` operation for the JS client, I've encountered an issue with how the exec parameters and return types are marshalled. 

The essence of the problem is that the server marshalls these objects instead of having the client drive how these are marshalled. As a result of this, for a JS or C++ client to be able to use `exec` with default configuration, they need to understand JBoss Marshaller format, which is not good.

I'm not sure this would have been unavoidable due to the characteristics of `exec` but I wanted to see if we can find a good way to solve or get around this issue. Long term, we need better encoding handling both for incoming and returning types, but the question is whether we can find a way to better solve this until then. Here are some options:

- For the C++ client, Vittorio has part implemented the JBoss Marshaller format [1], but I'm kinda reluctant to go down this path since that creates a lot of work for us as the number of types that can be discovered in a JBoss Marshaller format byte array are quite considerable [2]. We're bound to miss one of those and since clients could execute any script, the chances are high IMO...

- An alternative would be for the JS/C++ clients to only support exec when the marshaller is one that enables compatibility mode. The idea here is that for compatibility mode to work, all clients involved are going to be set up with a marshaller that can work for all of them. Working on such marshaller is time better spent than on implementing the JBoss Marshaller format. We had a separate discussion on this topic in another dev thread...

Any other ideas someone might have?

Cheers,

[1] https://github.com/infinispan/cpp-client/blob/master/include/infinispan/hotrod/JBasicMarshaller.h
[2] https://github.com/jboss-remoting/jboss-marshalling/blob/master/river/src/main/java/org/jboss/marshalling/river/Protocol.java
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Galder Zamarreño
Infinispan, Red Hat