Simple, perfectly reproducible, environments with nix specified using an YAML file.

Example, write to a file called env.nml:

nixml: v0.0
snapshot: stable-19.03
packages:
  - lang: python
    version: 2
    modules:
      - numpy
      - scipy
      - matplotlib
      - mahotas
      - jupyter
      - scikitlearn

Now, run

nixml shell

and you will be dropped into an environment containing the packages listed above, as was up to date in March 2019. Conceptually, the environment will always be generated from scratch, but caching means that the first time will take significantly longer (including, it will download all dependencies). Afterwards, it should take a few seconds at most.

This environment will be like a typical conda/pip/virtualenv/... environment: if will place the corresponding binaries at the front of the PATH so that they are picked with high priority, but, alternatively, you can generate a pure environment, which will contain only the packages that you specify. This avoids accidental use of packages that are not part of the environment:

nixml shell --pure

Finally, you can run

nixml generate

to just create the nixml.nix corresponding to the enviroment.

• Python
• nix

It's a YaML file

nixml: version of nixml to use. Currently, only v0.0 is supported.

snapshot: This is the package version to use. Currently, only stable-19.03 is available, but general syntax is {stable,unstable}-{year}.{month}.

packages: A list of packages, which are grouped into language blocks. Currently supported:

• python: Python language environment, specify the version (version) and modules.
• texlive: Texlive packages
• nix: Generic packages (i.e., vim or bash)

• Luis Pedro Coelho (email: [email protected] on twitter: @luispedrocoelho)