How to set specific environment variables when activating conda environment?

Does anyone know how to automatically set environment variables when activating an env in conda? I have tried editing */bin/activate, but that adds the new environment variables for every new env that is created. I want to set env variables that are specific to each env.

Solution 1:

Use the files $CONDA_PREFIX/etc/conda/activate.d and $CONDA_PREFIX/etc/conda/deactivate.d, where $CONDA_PREFIX is the path to the environment.

See the section on managing environments in the official documentation for reference.

Solution 2:

Environment Variables as Configuration Settings

Conda v4.8 introduced a new command-line interface in the conda-env tool for managing environment variables on a per-environment basis. The command is conda env config vars and here is the help description as of v4.8.3 for the command overall:

$ conda env config vars -h
usage: conda-env config vars [-h] {list,set,unset} ...

Interact with environment variables associated with Conda environments

Options:

positional arguments:
  {list,set,unset}
    list            List environment variables for a conda environment
    set             Set environment variables for a conda environment
    unset           Unset environment variables for a conda environment

optional arguments:
  -h, --help        Show this help message and exit.

examples:
    conda env config vars list -n my_env
    conda env config vars set MY_VAR=something OTHER_THING=ohhhhya
    conda env config vars unset MY_VAR

Perhaps a bit verbose, but it avoids having to manually manage files in etc/conda/(de|)activate.d.

YAML Specification

Added in Conda v4.9, there is now support for automatic defining of environment-specific variables as part of an environment YAML definition. For example,

name: foo
channels:
  - defaults
dependencies:
  - python
variables:
  MY_VAR: something
  OTHER_VAR: ohhhhya

which would set up the environment variables MY_VAR and OTHER_VAR to be set and unset on environment activation and deactivation, respectively.