Python: Derive FluxExecutor from concurrent.futures.Executor

[jan-janssen]

In analogy to the FluxExecutorFuture being derived from concurrent.futures.Future now also the FluxExecutor is derived from concurrent.futures.Executor . This has two advantages, on the one hand the __enter__() and __exit__() functions are already defined and on the other hand frameworks which integrate interfaces for multiple Executors can check for classes derived from the concurrent.futures.Executor class.

[jameshcorbett]

When I wrote it I made a choice not to derive FluxExecutor from concurrent.futures.Executor, because the interface isn't the same. You can't take a FluxExecutor and treat it like an Executor. As the docstring of the class says:

    Inspired by the ``concurrent.futures.Executor`` class, with the following
    interface differences:

        - the ``submit`` method takes a ``flux.job.Jobspec`` instead of a
          callable and its arguments, and returns a ``FluxExecutorFuture``
          representing that job.
        - the ``map`` method is not supported, given that the executor consumes
          Jobspecs rather than callables.

I think these differences are significant and make it so that isinstance(FluxExecutor(), Executor) checks should not pass. Can you explain why you think they should pass?

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The diff coverage is 100.00%.

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Impacted Files	Coverage Δ
src/bindings/python/flux/job/executor.py	94.33% <100.00%> (ø)

[jan-janssen]

I think these differences are significant and make it so that isinstance(FluxExecutor(), Executor) checks should not pass. Can you explain why you think they should pass?

Makes sense - thanks for the explanation.