Multienv

• Requirements Installation
• Pyenvs
• Pyenvs config

Requirements Installation

multienv requires python>=12 and uses pyyaml.

It can be installed using pip:

pip install multienv

Or using conda refering to the cosmoloj channel:

conda install multienv -c cosmoloj

Pyenvs

pyenvs is a tool of python configuration file management.

usage: pyenvs [-h] {info,config} ...

Multi environment management.

positional arguments:
  {info,config}  available commands
    info         get general info
    config       generates environment configurations

options:
  -h, --help     show this help message and exit

Pyenvs config

usage: pyenvs config [-h] [--encoding [ENCODING]] [--output [OUTPUT]] [file]

positional arguments:
  file                  path to the configuration file

options:
  -h, --help            show this help message and exit
  --encoding [ENCODING]
                        the configuration file encoding (default to utf-8)
  --output [OUTPUT]     the environment file output directory

The pyenvs config command parameterizes environment/requirement files by environments.

For instance, suppose you have to maintain a python program using multienv as a dependency.

Setting a Conda environment will resemble to setting a file like this (environment_strict.yml):

dependencies:
- python=3.12

But testing purposes would require to add some dependencies specific to the testing environment. For instance (environment_pytest.yml):

dependencies:
- python=3.12
- pytest=7.4.4

Similarly, running a linter would require another specific environment (environment_pylint.yml):

dependencies:
- python=3.12
- pylint=3.2.2

And running a linter for the test files, would require another one (environment_pylint_pytest.yml):

dependencies:
- python=3.12
- pylint=3.2.2
- pytest=7.4.4

Defining environment files is one of the way to proceed, but manually adding dependencies to an environment defined by a minimal dependency file is another one, although less synthetic. Compare:

conda env create -n default -f environment_strict.yml
conda env create -n pylint_pytest -f environment_strict.yml
conda install pylint=3.2.2 pytest=7.4.4
conda env create -n pylint -f environment_strict.yml
conda install pylint=3.2.2
conda env create -n pytest -f environment_strict.yml
conda install pytest=7.4.4

to:

conda env create -n pylint_pytest -f environment_strict.yml
conda env create -n pylint_pytest -f environment_pylint_pytest.yml
conda env create -n pylint_pytest -f environment_pylint.yml
conda env create -n pylint_pytest -f environment_pytest.yml

Both ways to proceed implies maintaining a coherent set of dependency versions in several places, either in command line arguments or in environment files. The purpose of pyenvs config is to manage a coherent dependency version set in a single configuration files from which generating all the specific environment files.

The configuration mapping the previous environment definitions is specified in a single multienv.yml file. multienv.yml is the default configuration file name, located by default in the current working directory.

configuration:
  formatters:
    - conda:
        strict_environment: strict

dependencies:
  - id: python
    version: '3.12'
  - id: pylint
    version: 3.2.2
    environments: [lint]
  - id: pytest
    version: 7.4.4
    environments: [test]

Running:

pyenvs config

Generates three environment files. The strict environment only includes the dependencies without specific environment. Those dependencies are interpreted to be strictly necessary to all environments as functional dependencies of the program.

The environment_strict.yml conda environment file:

name: strict
dependencies:
- python=3.12

Other dependencies enumerates environment tags which are used to defines each one an environment adding to the stric dependencies, all the dependencies mentioning the environment tag.

The environment_lint.yml conda environment file:

name: lint
dependencies:
- python=3.12
- pylint=3.2.2

The environment_test.yml conda environment file:

name: test
dependencies:
- python=3.12
- pytest=7.4.4

The strict environment is only generated because it is explicitly parameterized with a name ("strict") in the configuration file. In a same way, a default environment file in only generated if the configuration file contains a parameter given its name.

configuration:
  formatters:
    - conda:
        strict_environment: strict
        default_environment: default

dependencies:
  - id: python
    version: '3.12'
  - id: pylint
    version: 3.2.2
    environments: [lint]
  - id: pytest
    version: 7.4.4
    environments: [test]

Using this updated environment file would have produced one more environemnt_default.yml conda environment file:

name: default
dependencies:
- python=3.12
- pylint=3.2.2
- pytest=7.4.4

From now, all the dependency versions can be managed from a single configuration files for all the environment needed by the contextual usage of the program.