Drop python-daemon and write our own daemon code

[moggers87]

Related to #89

Python-daemon has caused multiple issues in the past and is causing issues again. I'm not particularly happy with the developer's response either, it was basically "don't use pip as it doens't support setup_requires"... which is great except setup_requires is not standard and I don't want to go back to using easy_install... And why does the project need docutils in the first place?

Anyway!

The project isn't too big, we can probably strip what we don't need/are not interested in. The project is a mixed bag of Apache and GPLv3 licensed code - both which allow us to do what needs to be done.

[moggers87]

Also worth noting that lockfile (a dependency of python-daemon) is marked as deprecated by its author.

[jluttine]

Are you aware that there are any compatibility issues in using >2.2.0 of python-daemon? I installed python-daemon 2.2.3 and all unit tests of salmon passed so to me it seems ok.

[moggers87]

@jluttine yes, see #89 and https://pagure.io/python-daemon/issue/18

However, it seems that this commit: https://pagure.io/python-daemon/c/8352cace3ac22090474b40feed9e83f94e9d3e9e might have solved the actual issue.

[moggers87]

See #100 - will be interesting to see if it now installs correctly on pypy or not.

[moggers87]

#100 has been merged, thanks for prodding me to look into this again @jluttine 👍

[moggers87]

I'd still like to remove python-daemon, especially as it still relies on lockfile (which is deprecated) and I don't trust the author not to break pip installing again given the response received on https://pagure.io/python-daemon/issue/18

I'd consider this a low priority (at least until something breaks again 🙃 )

[jluttine]

Thanks! Not sure if related, but do you have any ideas why the current release fails unit tests on MacOS 10.13? https://gist.github.com/risicle/0b9e661fa0dc49d6f92d9225f6f5c86c

[moggers87]

The exceptions are coming from Python's mailbox module - it looks like a write permission error.