A very small framework for a very simple pattern: most networking daemon apps fetch data from some source, parse that data, and, based on data contents, send it elsewhere.

Just because I'm so tired seeing daemon logic, fetching logic, and sending logic all in one place.

You probably won't want to use this for low-level networking. I intend this to be used in the OSI Application Layer.

As simple as...

import pytheas.patterns
import pytheas.sfdaemon

class MyFetcher(pytheas.patterns.Fetcher):
    def fetch(self):
        # Implementations go

class MySender(pytheas.patterns.Sender):
    def send(self, data):
        # Implementations go

if __name__ == "__main__":
    myfetcher = MyFetcher()
    mysender = MySender()
    daemon = pytheas.sfdaemon.Pytheas(myfetcher, mysender)
    daemon.run()

Then, invoke your code as follows to properly daemonize:

nohup python codesrc.py > codesrc.out 2> &1 &

See this StackOverflow answer for more details on the invocations.

See the examples for concrete examples.

Yah. The early stages of this project wanted to feature the capability of creating daemons without having to use nohup and all those sigils. It used python-daemon to achieve that effect. However, as of this writing, it has been more than four years since python-daemon was last updated and, as I found out, python-daemon is not compatible with gevent.

geventdaemon looks worth a try but (again as of this writing) it has been two years since the last commit so I'm not expecting much.

If you want to give it a try (or maybe hack your own compatibility layer), just give me a shout (or a pull request).

You can communicate with a running daemon via the command server. By default, Pytheas listens to port 16981. You can specify your own port via the constructor of Pytheas.

pytheas.sfdaemon.Pytheas(fetcher, sender, port=8888)

You can also create your own command handler and pass it to the Pytheas constructor as follows:

TODO: Expand on this

pytheas.sfdaemon.Pytheas(fetcher, sender, command_interpreter=my_interpreter)

Q: I'm stingy with ports and don't need to signal to my daemons anyway. Can I instruct Pytheas to not run the command server?
A: Yes. Just pass port=None to the Pytheas constructor.

Q: What's the format for commands?
A: You can specify your own format for your own interpreter as long as it takes the newline character (\n) as a terminator. However, the reserved commands of Pytheas use JSON so you may want to adopt that for the sake of world peace.

Q: What are Pytheas' reserved commands?
A: Coming soon...

Wanted: more tests. Never used in production anywhere. Very proof-of-concept.

See also, todo below.

Linux? Yes.

Mac? Should be.

Windows? Windows?

More tests. Make stuff configurable. Did I mention more tests? What about better tests?

Also...

• Ensure fail-fast behavior.
• Allow for different fetch-send patterns (basic, queued, etc.).
• Add kill signal.

The examples fetch and send via Redis queues. The import path assume that Pytheas is installed in your system. This package is now in PyPI so just do

pip install Pytheas

The MIT License (MIT)

Copyright (c) 2014 Christian Andrei Estioco

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

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