Automatically activate conda environments in zsh

conda_auto_env.zsh

# Auto activate conda environments
# - If an `environment.yml` or `.venv` file is in the current directory,
#   the environment specified by that file is activated
#     - `environment.yml` files are parsed
#     - `.venv` files must contain just the name of the environment
# - If no such files are present and no environment is already activated, then
#   we try to activate an environment with the same name as the current directory
# - Assumes that the conda installation is at $HOME/miniconda3
# Modified from:
# https://github.com/chdoig/conda-auto-env
conda_auto_env() {
  # Get environment name from files if available
  if [ -e "environment.yaml" ]; then
    # Parse environment.yml file
    ENV_NAME=$(head -n 1 environment.yaml | cut -f2 -d ' ')
  elif [ -e ".venv" ]; then
    # Parse the .venv file
    ENV_NAME=$(cat .venv)
  fi
  # If we're not in that environment now, try to activate it
  if [[ $CONDA_PREFIX != *$ENV_NAME* ]]; then
    source activate $ENV_NAME &>/dev/null
  # Otherwise, if we're not in any environment, check if the current
  # directory name is an environment and try to activate that
  elif [[ $CONDA_PREFIX == '' ]]; then
    # Get current directory name
    CWD=$(basename $(pwd))
    if [[ -e "$HOME/miniconda3/envs/$CWD" ]]; then
      source activate $CWD &>/dev/null
    fi
  fi
}