venvfromfile

A simple runnable Python package that sets up virtual environments as specified in a configuration file using the builtin venv module.

Examples

The configuration files for the construction of virtual environments are .yaml files like the following example (compare venv_devel.yaml in the root directory of this repo):

min_version: ">=3.7"
venv_configs:
  - directory: venv@venvfromfile
    requirement_files:
    - requirements.txt
    pth_paths:
    - src

This constructs a virtual environment next to the configuration file if at least Python 3.7 is used. The directory will be named "venv@venvfromfile" and requirements from a file "requirements.txt" which should be placed next to the configuration file will be installed in the virtual environment. Additionally, a file "venv@venvfromfile.pth" is installed in the virtual environment containing the path to the directory "src" relative to the configuration file. This instructs Python to search this path for installed packages when importing. More information on .pth files can be found in the documentation of the site module (builtin).

Note that all relative paths specified in the configuration files are interpreted relative to the configuration file. This includes, for example the directory names of the virtual environment.

For further information on the available options see the classes contained in the conf.py module and their fields' docstrings.

In order to construct the virtual environment specified by the file above, the package can be invoked as

python -m venvfromfile filename.yaml

where filename.yaml is the file name of the configuration file.

For further information on available command line options type

python -m venvfromfile -h

Another simple example:

min_version: ">=3.7"
venv_configs:
  - directory: py37
    max_version: "<=3.7"
  - directory: py38_39
    min_version: ">=3.8"
    max_version: "<3.10"

This would construct a plain virtual environment without any requirements in the "py37" directory if Python version 3.7 or below is used and in the "py38_39" directory if the Python version is above 3.8 and strictly below 3.10. Note that the first comparison will only hold for Python version 3.7 exactly, since the entire config only applies to Python versions 3.7 and above.

Installation

You can install this package directly from git:

pip install git+https://github.com/devds96/venvfromfile

Alternatively, clone the git repo and run in its root directory:

pip install .