[ovirt-devel] Vdsm api package

[Nir Soffer]

Hi all,

In the Vdsm call, we discussed a way to expose vdsm errors to its clients
(e.g, engine, hosted engine agent/setup).

The idea is to have a vdsmapi package, holding:
- errors.py - all public errors
- events.py - all events sent by vdsm
- client.py - library for communicating with vdsm
- schema.py - the client will use this to autogenerate online help and
validate messages
- schema.yaml - we probably need several files (gluster, events, etc.)

This will allow other projects talking with vdsm to do:

    from vdsmapi import client, errors
    ...
    try:
        client.list(vmId="xxxyyy")
    except errors.NoSuchVM:
        ...

(this is a fake example, the real api may be different)

Engine can build-require vdsmapi, and generate java module with the
public errors from
vdsmapi/errors.py module, instead of keeping this hardcoded in engine,
and updating
it every time vdsm adds new public error.

Vdsm will use this package when building response to clients.

Edi was concerned about sharing the errors module, so maybe we need a package:

vdsmapi/
    errors/
        network.py
        virt.py
        storage.py
        gluster.py

We can still expose all the errors via errors/__init__.py, so clients
do not have to care about
the area of the application the error come from.

Thoughts?

Nir