environment.yml

conda-lock has first class support for environment.yml files.

If no --file argument is specified conda-lock will look for an environment.yml file in the current directory.

Basic example

environment.yml

channels:
  - conda-forge
dependencies:
  - python=3.9
  - pandas

Extensions

conda-lock makes use of a number of non-standard extensions to the format in order to enable additional functionality.

Platform specification

You may specify the platforms you wish to target by default directly in an environment.yml using the (nonstandard) platforms key:

environment.yml

channels:
  - conda-forge
dependencies:
  - python=3.9
  - pandas
platforms:
  - osx-arm64
  - linux-64

If you specify target platforms on the command line with -p, these will override the values in the environment specification. If neither platforms nor -p are provided, conda-lock will fall back to a default set of platforms.

Categories

You may wish to split your dependencies into separate files for better organization, e.g. a environment.yml for production dependencies and a dev-environment.yml for development dependencies. You can assign all the dependencies parsed from a single file to a category using the (nonstandard) category key.

dev-environment.yml

channels:
  - conda-forge
dependencies:
  - pytest
  - mypy=0.910
category: dev

The default category is main.

These can be used in a compound specification as follows.

conda-lock --file environment.yml --file dev-environment.yml

Preprocessing Selectors

You may use preprocessing selectors supported by conda-build meta.yaml files to specify platform-specific dependencies.

environment.yml

channels:
  - conda-forge
dependencies:
  - python=3.9
  - pywin32 # [win]
platforms:
  - linux-64
  - win-64

There are currently some limitations to selectors to be aware of: - Only OS-specific selectors are currently supported. See Conda's documentation for the list of supported selectors. Selectors related to Python or Numpy versions are not supported - conda-lock supports an additional unique selector osx64. It is true if the platform is macOS and the Python architecture is 64-bit and uses x86. - not, and, and or clauses inside of selectors are not supported - Comparison operators (==, >, <, etc) are not supported