Using setup.py to install python project as a systemd service

Question

I have a python project and I want to be able to install it using something like python setup.py install so that the installation automatically creates a systemd service.

I'm having some trouble, most probably setting the paths or imports correctly.

My environment:

• Ubuntu 15.04
• Python 2.7 (although it would be great to make it work in py3 too).

Project Structure:

+ top-folder
  + super_project
    + folder1
      __init__.py
      file1.py
    + folder2
      __init__.py
      file2.py
    __init__.py
    main.py
  setup.py
  setup.cfg

setup.py:

from setuptools.command.install import install
from setuptools import setup, find_packages
import subprocess
import os


class CustomInstallCommand(install):

  def run(self):
    install.run(self)
    current_dir_path = os.path.dirname(os.path.realpath(__file__))
    create_service_script_path = os.path.join(current_dir_path, 'super_project', 'install_scripts', 'create_service.sh')
    subprocess.check_output([create_service_script_path])

setup(
  name='super-project',
  author='Myself',
  version='0.0.1',
  description='My Description',
  packages=find_packages(exclude=['contrib', 'docs']),
  # this will create the /usr/local/bin/super-project entrypoint script
  entry_points={
    'console_scripts': [
      'super-project = super_project.main:main'
    ]
  },
  cmdclass={'install': CustomInstallCommand}
)

main.py

from super_project.folder1.file1 import Class1
from super_project.folder2.file2 import Class2
import logging


def main():
  logging.info('Executing super-project...')
  (...)
  logging.info('super-project execution finished.')

if __name__ == '__main__':
  main()

setup.cfg

[bdist_wheel]
universal=1

create_service.sh (more or less):

SYSTEMD_SCRIPT_DIR=$( cd  $(dirname "${BASH_SOURCE:=$0}") && pwd)
cp -f "$SYSTEMD_SCRIPT_DIR/super-project.service" /lib/systemd/system
chown root:root /lib/systemd/system/super-project.service

systemctl daemon-reload
systemctl enable super-project.service

super-project.service

[Unit]
Description=Super Description

[Service]
Type=simple
ExecStart=/usr/local/bin/super-service
Restart=always

[Install]
WantedBy=multi-user.target

The installation of the package generates the following output:

$ sudo python setup.py install --record files.txt
running install
running build
running build_py
copying super_project/main.py - build/lib.linux-x86_64-2.7/super_project
running install_lib
copying build/lib.linux-x86_64-2.7/super_project/__init__.py - /usr/local/lib/python2.7/dist-packages/super_project
copying build/lib.linux-x86_64-2.7/super_project/main.py - /usr/local/lib/python2.7/dist-packages/super_project
copying build/lib.linux-x86_64-2.7/super_project/db/__init__.py - /usr/local/lib/python2.7/dist-packages/super_project/db
copying build/lib.linux-x86_64-2.7/super_project/db/db_gateway.py - /usr/local/lib/python2.7/dist-packages/super_project/db
(...)
byte-compiling /usr/local/lib/python2.7/dist-packages/super_project/__init__.py to
__init__.pyc
byte-compiling /usr/local/lib/python2.7/dist-packages/super_project/main.py to
main.pyc
byte-compiling /usr/local/lib/python2.7/dist-packages/super_project/db/__init__.py to
__init__.pyc
byte-compiling /usr/local/lib/python2.7/dist-packages/super_project/db/db_gateway.py
to db_gateway.pyc
(...)
running install_egg_info
running egg_info
writing requirements to super_project.egg-info/requires.txt
writing super_project.egg-info/PKG-INFO
writing top-level names to super_project.egg-info/top_level.txt
writing dependency_links to super_project.egg-info/dependency_links.txt
writing entry points to super_project.egg-info/entry_points.txt
reading manifest file 'super_project.egg-info/SOURCES.txt'
writing manifest file 'super_project.egg-info/SOURCES.txt'
Copying super_project.egg-info to /usr/local/lib/python2.7/dist-packages/super_project-0.0.1.egg-info
running install_scripts
Installing ai-scenario-qa script to /usr/local/bin
writing list of installed files to 'files.txt'

The super-project file is created in /usr/local/bin:

#!/usr/bin/python
# EASY-INSTALL-ENTRY-SCRIPT: 'super-project==0.0.1','console_scripts','super-project'
__requires__ = 'super-project==0.0.1'
import sys
from pkg_resources import load_entry_point

if __name__ == '__main__':
    sys.exit(
        load_entry_point('super-project==0.0.1', 'console_scripts', 'super-project')()
    )

The installation seems successful, although:

$ systemctl status super-project.service
● super-project.service
   Loaded: not-found (Reason: No such file or directory)
   Active: inactive (dead)

The error I can see in /var/log/syslog:

 Feb 16 20:48:34  systemd[1]: Starting  Super Description...
 Feb 16 20:48:34  super-project[22517]: Traceback (most recent call last):
 Feb 16 20:48:34  super-project[22517]: File "/usr/local/bin/super-project", line 9, in <module
 Feb 16 20:48:34  super-project[22517]: load_entry_point('super-project==0.0.1', 'console_scripts', 'super-project')()
 Feb 16 20:48:34  super-project[22517]: File "/usr/lib/python2.7/dist-packages/pkg_resources/__init__.py", line 521, in load_entry_point
 Feb 16 20:48:34  super-project[22517]: return get_distribution(dist).load_entry_point(group, name)
 Feb 16 20:48:34  super-project[22517]: File "/usr/lib/python2.7/dist-packages/pkg_resources/__init__.py", line 2632, in load_entry_point
 Feb 16 20:48:34  super-project[22517]: return ep.load()
 Feb 16 20:48:34  super-project[22517]: File "/usr/lib/python2.7/dist-packages/pkg_resources/__init__.py", line 2312, in load
 Feb 16 20:48:34  super-project[22517]: return self.resolve()
 Feb 16 20:48:34  super-project[22517]: File "/usr/lib/python2.7/dist-packages/pkg_resources/__init__.py", line 2318, in resolve
 Feb 16 20:48:34  super-project[22517]: module = __import__(self.module_name, fromlist=['__name__'], level=0)
 Feb 16 20:48:34  super-project[22517]: ImportError: No module named main
 Feb 16 20:48:34  systemd[1]: super-project.service: main process exited, code=exited, status=1/FLURE
 Feb 16 20:48:34  systemd[1]: Unit super-project.service entered fled state.
 Feb 16 20:48:34  systemd[1]: super-project.service failed.
 Feb 16 20:48:34  systemd[1]: super-project.service holdoff time over, scheduling restart.
 Feb 16 20:48:34  systemd[1]: start request repeated too quickly for super-project.service
 Feb 16 20:48:34  systemd[1]: Failed to start Super Description.
 Feb 16 20:48:34  systemd[1]: Unit super-project.service entered fled state.
 Feb 16 20:48:34  systemd[1]: super-project.service failed.

As can be seen, the module main cannot be found. This is the main problem.

When changing code/conf, I remove the super-project/service as follows:

$ sudo systemctl disable super-project.service
$ sudo rm -f /lib/systemd/system/super-project.service
$ sudo systemctl daemon-reload
$ su
# cat files.txt | xargs rm -r

On the other hand:

• If I execute $ super-project from /usr/local/bin/, the script starts correctly (no import exception) but the configuration files cannot be read (most probably because of relative/absolute path issues).
• If I execute $ super-project from top-folder (folder containing the project code/files) the script runs perfectly

What am I missing? I've spend a lot of time searching what the issue might be. It seems that the package is correctly set up in the dist-packages directory and all the service files are correctly created once the setup is executed.

I've read things about using from __future__ import absolute_import, but I'm not sure if I have to add that to my main.py (it does not work) or to all the files in my project.

Answer 1

You get an ImportError, because the module in question is not in sys.path or not accessible, because of some file system permissions.
Here's a script to check file system permissions of a given distribution, group and name.

chk_perm.py

from pkg_resources import get_distribution
import os
import sys

dist, group, name = sys.argv[1:]
dist = get_distribution(dist)
location = dist.location
einfo = dist.get_entry_info(group, name)
if not einfo:
    print('No such group "{}" or name "{}"'.format(group, name))
    sys.exit(1)
m_name = einfo.module_name
path = format(os.path.join(location, *m_name.split('.')))
path = path if os.access(path, os.F_OK) else '{}.py'.format(path)
print('If path "{}" exists: {}'.format(path, os.access(path, os.F_OK) if path.endswith('.py') else True))
print('If path "{}" readable: {}'.format(path, os.access(path, os.R_OK)))

Test;

$ python chk_perm.py setuptools console_scripts easy_install
If path "lib/python2.7/site-packages/setuptools/command/easy_install.py" exists: True
If path "lib/python2.7/site-packages/setuptools/command/easy_install.py" readable: True

$ foo
Traceback (most recent call last):
  File "bin/foo", line 9, in <module>
    load_entry_point('mypkg==0.0.4', 'console_scripts', 'foo')()
  File "lib/python2.7/site-packages/pkg_resources/__init__.py", line 549, in load_entry_point
    return get_distribution(dist).load_entry_point(group, name)
  File "lib/python2.7/site-packages/pkg_resources/__init__.py", line 2542, in load_entry_point
    return ep.load()
  File "lib/python2.7/site-packages/pkg_resources/__init__.py", line 2202, in load
    return self.resolve()
  File "lib/python2.7/site-packages/pkg_resources/__init__.py", line 2208, in resolve
    module = __import__(self.module_name, fromlist=['__name__'], level=0)
ImportError: No module named main

$ python chk_perm.py mypkg console_scripts foo
If path "lib/python2.7/site-packages/pkg/main.py" exists: True
If path "lib/python2.7/site-packages/pkg/main.py" readable: False

$ ls -l lib/python2.7/site-packages/pkg/main.py 
-rw-rw---- 1 root root 104 Mar  6 22:52 lib/python2.7/site-packages/pkg/main.py

$ sudo chmod o+r lib/python2.7/site-packages/pkg/main.py
$ ls -l lib/python2.7/site-packages/pkg/main.py 
-rw-rw-r-- 1 root root 104 Mar  6 22:52 lib/python2.7/site-packages/pkg/main.py

$ python chk_perm.py mypkg console_scripts foo
If path "lib/python2.7/site-packages/pkg/main.py" exists: True
If path "lib/python2.7/site-packages/pkg/main.py" readable: True

$ foo
App is running