Provides the conda env interface to Conda environments.

To install conda env with conda, run the following command in your root environment:

$ conda install -c conda conda-env

All of the usage is documented via the --help flag.

$ conda env --help
usage: conda-env [-h] {create,export,list,remove} ...

positional arguments:
  {attach,create,export,list,remove,upload,update}
    attach              Embeds information describing your conda environment
                        into the notebook metadata
    create              Create an environment based on an environment file
    export              Export a given environment
    list                List the Conda environments
    remove              Remove an environment
    upload              Upload an environment to anaconda.org
    update              Updates the current environment based on environment
                        file

optional arguments:
  -h, --help            show this help message and exit

conda-env allows creating environments using the environment.yml specification file. This allows you to specify a name, channels to use when creating the environment, and the dependencies. For example, to create an environment named stats with numpy and pandas create an environment.yml file with this as the contents:

name: stats
dependencies:
  - numpy
  - pandas

Then run this from the command line:

$ conda env create
Fetching package metadata: ...
Solving package specifications: .Linking packages ...
[      COMPLETE      ] |#################################################| 100%
#
# To activate this environment, use:
# $ source activate numpy
#
# To deactivate this environment, use:
# $ source deactivate
#

Your output might vary a little bit depending on whether you have the packages in your local package cache.

You can explicitly provide an environment spec file using -f or --file and the name of the file you would like to use.

The default channels can be excluded by adding nodefaults to the list of channels. This is equivalent to passing the --override-channels option to most conda commands, and is like defaults in the .condarc channel configuration but with the reverse logic.

name: stats
channels:
  - javascript
dependencies:
  - python=3.4   # or 2.7 if you are feeling nostalgic
  - bokeh=0.9.2
  - numpy=1.9.*
  - nodejs=0.10.*
  - flask
  - pip:
    - Flask-Testing

Recommendation: Always create your environment.yml file by hand.

If you have jinja2 available in the environment, environment.yml files will be rendered with it before processing.

name: pytest
dependencies:
{% for i in ['xunit', 'coverage','mock'] %}
  - pytest-{{ i }}
{% endfor %}

In this example, the previous file with jinja2 syntax is equivalent to:

name: pytest
dependencies:
  - pytest-xunit
  - pytest-coverage
  - pytest-mock

When using jinja2, on top of the usual template capabilities, you have access to the following variables:

• root: The directory containing environment.yml
• os: Python's os module.

name: oracle
dependencies:
  - oracle_instantclient

# List type environment variables will be joined with os.pathsep (':' in unix, ';' in windows).
# These values will be inserted in front of any existing value in the current environment.
# e.g.:
#   current PATH: "/usr/local/bin:/usr/bin"
#   new     PATH: "{{ root }}/bin:/usr/local/bin:/usr/bin"
environment:
  - ORACLE_HOME: /usr/local/oracle_instantclient
  - PATH:
    - {{ root }}/bin

aliases:
  run_db: bash {{ root }}/bin/run_db.sh

You can use an includes tag to include content from other environment.yml files.

This tag is a list of paths to other environment files:

name: project_a
dependencies:
  - pytest

name: project_b
dependencies:
  - pytest-xunit
includes:
  - {{ root }}/project_a

In this example, the previous file for project_b is equivalent to:

name: project_b
dependencies:
  - pytest
  - pytest-xunit

conda-env will always try to maintain a proper dependency order (e.g. PATHs defined in A will appear before B, or, an alias defined in A will be overridden by an alias with the same name in B).