Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]


Groups > comp.lang.python > #77819

Python stdout goes where under systemd? (Was: Example of python service running under systemd?)

Subject Python stdout goes where under systemd? (Was: Example of python service running under systemd?)
From Travis Griggs <travisgriggs@gmail.com>
Date 2014-09-12 12:05 -0700
References (3 earlier) <20140911212921.GB26465@arxnet.hu> <5412548A.1090507@gmail.com> <CAPTjJmq4fYOs-qvko9q9S=M7PNGOLPBTDiPZ6R0PvMrAULC=3g@mail.gmail.com> <20140912061806.GB3333@arxnet.hu> <CAPTjJmqTYmGy8WHm5a3Vo-A+vXjoXJWf4C0Nr7qXeBuHSEC_AQ@mail.gmail.com>
Newsgroups comp.lang.python
Message-ID <mailman.13981.1410548753.18130.python-list@python.org> (permalink)

Show all headers | View raw


Thanks all for the help/advice. I’m getting there.

To experiment/learn, I made a simple python program (/Foo/cyclic.py):
 
    #!/usr/bin/env python3

    import time

    while True:
        time.sleep(5)	
        with open('sound', 'r') as file:
            currentValue = file.read()
        otherValue = 'tick' if currentValue == 'tock' else 'tock'
        with open('sound', 'w') as file:
            file.write(otherValue)
        print(currentValue, '->', otherValue)

Run from the command line, this tick-tocks nicely, both outputting, as well as updating the ‘/Foo/sound’ file on a 5 second period.

I then created a simple .service file:

    [Unit]
    Description=Foo for learning service
    After=network-online.target
    
    [Service]
    Type=simple
    ExecStart=/Foo/cyclic.py
    WorkingDirectory=/Foo
    StandardOutput=journal
    
    [Install]
    WantedBy=multi-user.target

I chose to be “explicit” with some of the default options (Type and StandardOutput).
I finally executed:

    systemctl --system daemon-reload
    systemctl enable foo
    systemctl start foo

It seems to work. Almost. The file is being updated regularly (watch cat /Foo/sound shows the change happening). But I can’t seem to find the output from my print() statement. journalctl -f doesn’t show anything. Nor does tail -f /var/log/syslog or any of the others. It just seems to be going nowhere? Is there something I need to do special to get the print() output going somewhere logable?

Back to comp.lang.python | Previous | Next | Find similar | Unroll thread


Thread

Python stdout goes where under systemd? (Was: Example of python service running under systemd?) Travis Griggs <travisgriggs@gmail.com> - 2014-09-12 12:05 -0700

csiph-web