Python Virtual Environment Setup in Jenkins
Python’s Virtual Environments Feature presents a unique opportunity with CI/CD tooling — where users congregate to publish and execute code of their own devising. Developers might use different versions of the same package (creating dependency conflicts), or they might simply need a newer version of a package than is on the system by default.
Or, with security-centric implementations, developers don’t get root access, which prevents package installation outside of userspace.
The Virtual Environments feature allows users to set up a container of sorts (albeit very limited) that permits installing of ephemeral packages (and specific package versions) to prevent dependency conflicts.
Prerequisites
Set Jenkins Global Parameters
Under Jenkins -> Manage Jenkins -> System, configure the Shell executable to /bin/bash. It's blank by default (Bourne Shell):
Install Packages (example from Debian 12)
Consuming Virtual Environments in a Jenkins Job
Consuming a virtual env ( venv) in Jenkins is now relatively straightforward. Here's an example from my Certificate Checker
1 python3 -m venv checkcerts_env 2 source checkcerts_env/bin/activate 3 python3 -m pip install requests ruamel.YAML pyOpenSSL fqdn 4 python3 check-certificates.py -f certs_list.jsonWith this example, I create a virtual environment (fresh every time) named checkcerts_env. It's not as necessary to create a venv with a unique name inside the Jenkins workspace if it's cleaned on run, but I prefer the extra safety.
The source command changes python3's environment to checkcerts_env. You can verify immediately after with:
1 (checkcerts_env) jenkins@localhost:~/workspace/certificate-tracker$ which python 2 /var/lib/jenkins/workspace/certificate-tracker/checkcerts_env/bin/pythonFrom there, pip can install packages unique to this ephemeral workspace. Keep in mind this will slow execution down quite a bit, which is a fair trade for reliable outcomes.
Originally published at https://blog.engyak.co on July 2, 2023.
