Unable to use Python keyring module from systemd service

Question

I want a python script to automatically start after boot on a linux computer. To achieve this I set up a systemd service:

[Unit]
Description=My Script Service
Wants=network-online.target
After=network-online.target
After=multi-user.target
StartLimitIntervalSec=3600
StartLimitBurst=60

[Service]
Type=idle
User=masterofpuppets
Restart=on-failure
RestartSec=60s
WorkingDirectory=/home/masterofpuppets
ExecStart=/home/masterofpuppets/mypythonscript.py

[Install]
WantedBy=multi-user.target

But I get an error:

sudo systemctl status mysystemd.service
● transfer_DB_remote_to_local.service - My Script Service
     Loaded: loaded (/etc/systemd/system/mysystemd.service; enabled; vendor preset: enabled)
     Active: activating (auto-restart) (Result: exit-code) since Mon 2022-11-21 11:49:46 CET; 55s ago
    Process: 19283 ExecStart=/home/masterofpuppets/mypythonscript.py (code=exited, status=1/FAILURE)
   Main PID: 19283 (code=exited, status=1/FAILURE)

The python script is

#!/usr/bin/env python3
# -*- coding: utf-8 -*-

import subprocess
import keyring
import time

DB_backup_from_server = f"mysqldump --single-transaction --quick -v -h 192.168.0.97 -u {keyring.get_password('serverDB', 'user')} -p'{keyring.get_password('serverDB', 'pw')}' testDB > ~/testDB_backup.sql"
restore_backup_to_local_DB = f"mysql -v -u {keyring.get_password('mysqlDB', 'user')} -p'{keyring.get_password('mysqlDB', 'pw')}' testDB < ~/testDB_backup.sql"

commands = [DB_backup_from_server, restore_backup_to_local_DB]

execution_interval = 60*60
t0 = time.time() - execution_interval
while True:
    if time.time() - t0 > execution_interval:
        t0 = time.time()
        for cmd in commands:
            subprocess.run(cmd, 
                            stdout = subprocess.PIPE, 
                            universal_newlines = True,
                            shell = True)
    time.sleep(60)

There are no errors if I start it manually.

This is a similar issue, but the suggested solution doesn't help in my case.

Edit:

journalctl -u mysystemd.service
Nov 21 14:36:37 masterofpuppets-pc systemd[1]: Started My Script Service.
Nov 21 14:36:38 masterofpuppets-pc mypythonscript.py[47110]: Traceback (most recent call last):
Nov 21 14:36:38 masterofpuppets-pc mypythonscript.py[47110]:   File "/home/masterofpuppets/mypythonscript.py
Nov 21 14:36:38 masterofpuppets-pc mypythonscript.py[47110]:     DB_backup_from_server = f"mysqldump --single-transaction --quick -v -h 192.168.0.38 -u {keyring.get_>
Nov 21 14:36:38 masterofpuppets-pc mypythonscript.py[47110]:   File "/usr/lib/python3/dist-packages/keyring/core.py", line 57, in get_password
Nov 21 14:36:38 masterofpuppets-pc mypythonscript.py[47110]:     return _keyring_backend.get_password(service_name, username)
Nov 21 14:36:38 masterofpuppets-pc mypythonscript.py[47110]:   File "/usr/lib/python3/dist-packages/keyring/backends/fail.py", line 25, in get_password
Nov 21 14:36:38 masterofpuppets-pc mypythonscript.py[47110]:     raise NoKeyringError(msg)
Nov 21 14:36:38 masterofpuppets-pc mypythonscript.py[47110]: keyring.errors.NoKeyringError: No recommended backend was available. Install a recommended 3rd party bac>
Nov 21 14:36:38 masterofpuppets-pc systemd[1]: mysystemd.service: Main process exited, code=exited, status=1/FAILURE
Nov 21 14:36:38 masterofpuppets-pc systemd[1]: mysystemd.service: Failed with result 'exit-code'.
Nov 21 14:37:38 masterofpuppets-pc systemd[1]: mysystemd.service: Scheduled restart job, restart counter is at 143.
Nov 21 14:37:38 masterofpuppets-pc systemd[1]: Stopped My Script Service.

Check if there is something in the logs journalctl -u mysystemd. — VPfB
– VPfB, Commented Nov 21, 2022 at 13:05
there seems to be a problem with keyring, but I don't know how to fix it. — masterofpuppets
– masterofpuppets, Commented Nov 21, 2022 at 13:48
Anyhow, if you're running this as a system service, it's not supposed to be running as your user account, so there's no reasonable expectation for it to have access to any individual user's keyring. The details depend on the specific implementation, but many keyrings aren't available unless they're running as part of a logged-in user's graphical session. You could create a user service that's part of your session (thus only running when you're logged in), and it might not have this issue. — Charles Duffy
– Charles Duffy, Commented Nov 21, 2022 at 13:49
Store the password in a file: serverfault.com/questions/110738/… Do not use command line options to specify a password, it is not secure. — VPfB
– VPfB, Commented Nov 21, 2022 at 15:39
That's true. Putting a password in a command line completely negates any advantages you would have gotten from using a keyring in the first place; it's visible to anyone who looks at ps at the right moment (before mysql redacts it, which can only happen after its startup has finished). — Charles Duffy
– Charles Duffy, Commented Nov 21, 2022 at 15:50

masterofpuppets · Accepted Answer · 2022-11-21 20:27:38Z

0

Thanks to the hints, I now got it working via a user unit service. The file is located at ~/.config/systemd/user/myuserunit.service

[Unit]
StartLimitIntervalSec=3600
StartLimitBurst=60

[Service]
Type=simple
Restart=on-failure
RestartSec=60s
ExecStart=/home/masterofpuppets/mypythonscript.py

[Install]
WantedBy=default.target

enabling the service

systemctl --user daemon-reload
systemctl --user enable myuserunit.service

Now it automatically starts after reboot/login.

answered Nov 21, 2022 at 20:27

masterofpuppets

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