I've got a Windows 7 environment where I need to develop a Python Windows Service using Python 3.4. I'm using pywin32's win32service module to setup the service and most of the hooks seem to be working ok.
The problem is when I attempt to run the service from source code (using python service.py install
followed by python service.py start
). This uses PythonService.exe to host service.py - but I'm using a venv virtual environment and the script can't find it's modules (error message discovered with python service.py debug
).
Pywin32 is installed in the virtualenv and in looking at the source code of PythonService.exe, it dynamically links in Python34.dll, imports my service.py and invokes it.
How can I get PythonService.exe to use my virtualenv when running my service.py?
Thanks very much for posting this question and a solution. I took a slightly different approach which might also be useful. It is pretty difficult to find working tips for Python services, let alone doing it with a virtualenv. Anyway...
This is using Windows 7 x64, Python 3.5.1 x64, pywin32-220 (or pypiwin32-219).
C:\Python35\python -m venv myvenv
call myvenv\scripts\activate.bat
pip install pypiwin32
, pip install path\to\pywin32.whl
python myvenv\Scripts\pywin32_postinstall.py -install
.
C:\Windows\System32
. The DLL's are named pythoncom35.dll
and pywintypes35.dll
. So virtual environments on the same machine on the same major Python point release will share these... it's a minor tradeoff :)myvenv\Lib\site-packages\win32\pythonservice.exe
to myvenv\Scripts\pythonservice.exe
_exe_path_
to point to this relocated exe. This will become the service binPath. For example: _exe_path_ = os.path.join(*[os.environ['VIRTUAL_ENV'], 'Scripts', 'pythonservice.exe'])
.I think why this works is that Python looks upwards to figure out where the Libs folders are and based on that sets package import paths, similar to the accepted answer. When pythonservice.exe is in the original location, that doesn't seem to work smoothly.
It also resolves DLL linking problems (discoverable with depends.exe from http://www.dependencywalker.com/). Without the DLL business sorted out, it won't be possible to import from the *.pyd files from venv\Lib\site-packages\win32
as modules in your scripts. For example it's needed allow import servicemanager
; as servicemanager.pyd
is not in the package as a .py file, and has some cool Windows Event Log capabilities.
One of the problems I had with the accepted answer is that I couldn't figure out how to get it to accurately pick up on package.egg-link paths that are created when using setup.py develop
. These .egg-link files include the path to the package when it's not located in the virtualenv under myvenv\Lib\site-packages
.
If it all went smoothly, it should be possible to install, start and test the example win32 service (from an Admin prompt in the activated virtualenv):
python venv\Lib\site-packages\win32\Demos\service\pipeTestService.py install
python venv\Lib\site-packages\win32\Demos\service\pipeTestService.py start
python venv\Lib\site-packages\win32\Demos\service\pipeTestServiceClient.py
Another important note in all this is that the service will execute the python code in a completely separate environment to the one you might run python myservice.py debug
. So for example os.environ['VIRTUAL_ENV']
will be empty when running the service. This can be handled by either:
os.environ
.I read all the answers, but no solution can fix my problem.
After carefully researched David K. Hess's code, I made some change, and it finally works.
But my reputation doesn't enough, so I just post the code here.
# 1. Custom your Project's name and Virtual Environment folder's name
# 2. Import this before all third part models
# 3. If you still failed, check the link below:
# https://stackoverflow.com/questions/34696815/using-pythonservice-exe-to-host-python-service-while-using-virtualenv
# 2019-05-29 by oraant, modified from David K. Hess's answer.
import os, sys, site
project_name = "PythonService" # Change this for your own project !!!!!!!!!!!!!!
venv_folder_name = "venv" # Change this for your own venv path !!!!!!!!!!!!!!
if sys.executable.lower().endswith("pythonservice.exe"):
# Get root path for the project
service_directory = os.path.abspath(os.path.dirname(__file__))
project_directory = service_directory[:service_directory.find(project_name)+len(project_name)]
# Get venv path for the project
def file_path(x): return os.path.join(project_directory, x)
venv_base = file_path(venv_folder_name)
venv_scripts = os.path.join(venv_base, "Scripts")
venv_packages = os.path.join(venv_base, 'Lib', 'site-packages')
# Change current working directory from PythonService.exe location to something better.
os.chdir(project_directory)
sys.path.append(".")
prev_sys_path = list(sys.path)
# Manually activate a virtual environment inside an already initialized interpreter.
os.environ['PATH'] = venv_scripts + os.pathsep + os.environ['PATH']
site.addsitedir(venv_packages)
sys.real_prefix = sys.prefix
sys.prefix = venv_base
# Move some sys path in front of others
new_sys_path = []
for item in list(sys.path):
if item not in prev_sys_path:
new_sys_path.append(item)
sys.path.remove(item)
sys.path[:0] = new_sys_path
How to use it? It's simple, just paste it into a new python file, and import it before any third part model like this:
import service_in_venv # import at top
import win32serviceutil
import win32service
import win32event
import servicemanager
import time
import sys, os
........
And now you should fix your problem.
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