The post_process() method is skipped if `db_transaction = False`

If you set db_transaction = False on your service and implement a post_process() method, the post process method does not execute. While examining the code, it makes sense why because the on transaction commit hook is being used. However, the behavior is a bit obtuse especially if you are not familiar with the internals of the library.

The solution I propose is if db_transaction = False and a post_process() is implemented, then automatically execute the post_process() in sequence after the process(). This would be useful for services where transaction safety is not needed (like an API call, etc.) and would make the feature in parity when db_transaction = True.

I do believe it’s as easy as implementing a finally statement:

    @contextmanager
    def _process_context(self):
        """
        Returns the context for :meth:`process`
        :return:
        """
        if self.db_transaction:
            with transaction.atomic(using=self.using):
                if self.has_on_commit_action:
                    transaction.on_commit(self.post_process)
                yield
        else:
            try:
                yield
            finally:
                if self.has_on_commit_action:
                    self.post_process()

Note: I would likely rename has_on_commit_action to has_post_process_action since it would not be transaction related.

Alternatively, we could throw an exception if you define a post_process when transaction is false however I think making the feature act in parity is better.

Please let me know your thoughts and I’d be happy to make a PR.

[c17r]

Merged in #52, thanks!

[c17r]

I don’t think post_process should run if the main part of the process fails. I see the intent of post_process being for things like notifications/syncing/etc which shouldn’t fire if things have failed and the database hasn’t updated.

But I do think post_process should run regardless of the transaction setting as long as an exception doesn’t make it all the way to the library level.