.. post:: 2026-10-02
   :tags: conda-forge, recipe, recipe.yaml, conda
   :category: conda-forge
   :author: Tim Cera
   :location: Gainesville, FL
   :language: en

Version 1 of conda-forge recipe.yaml
------------------------------------
TLDR 1; Add "conda_build_tool: rattler-build" to "conda-forge.yml" and then
"conda smithy rerender".

TLDR 2; Maybe wait for conda-forge to convert the feedstocks to use the new
recipe.yaml format.

rattler-build is a new build tool for conda packages that is designed to be
faster and more efficient than the current conda-build tool.  It is the build
tool for version 1 of the conda-forge recipe.yaml format.

Three Blind Mice
-----------------
There are three ways to make a conda-forge recipe.yaml file:

* Convert recipe/meta.yaml to recipe/recipe.yaml with conda-recipe-manager.  In
  my opinion this was the best one.::

    # install conda-recipe-manager
    conda install conda-recipe-manager

    # typically run this in the root of the feedstock
    # I recommend using the --also-test-latest-python option to test the recipe
    # with the latest version of Python
    conda-recipe-manager convert --also-test-latest-python recipe/meta.yaml > recipe/recipe.yaml

* Use "grayskull" to create a fresh recipe.yaml file from "pypi".::

    # install grayskull
    conda install grayskull

    # typically run this in the root of the feedstock
    grayskull pypi <package-name> --use-v1-format --strict-conda-forge --output recipe/recipe.yaml

* Use "rattler-build" to create a fresh recipe.yaml file from "pypi".  This is
  the recommended way to create a new recipe.yaml file for conda-forge.::

    # install rattler-build
    conda install rattler-build

    # typically run this in the root of the feedstock
    rattler-build generate-recipe pypi --write <package-name>

There was no consistency in the three generated recipe.yaml files.  If you
already have a recipe/meta.yaml file, I recommend using the first method to
convert it to recipe.yaml.  If you are creating a new recipe.yaml file,
I recommend using the third method with rattler-build.

Clean Up
--------
If you are converting from and existing package, once you have a recipe.yaml
file, you have to delete the recipe/meta.yaml file.

Then there are some tools that you can use to check the recipe.yaml file for
errors.  I recommend::

    # install conda-smithy
    conda install conda-smithy

    # typically run this in the root of the feedstock
    # note you have to give it the directory of the recipe.yaml file, not the
    # file itself
    conda smithy recipe-lint recipe

    # then make sure it builds locally
    ./build-locally.py

The Undocumented
----------------
I could not find any documentation for this next part and only discovered by
looking at existing recipe.yaml feedstocks.  You must add the following to the
"conda-forge.yml" file in the root of the feedstock::

    conda_build_tool: rattler-build

Once you have that line added to the "conda-forge.yml" file, you have to run
"conda smithy rerender" to update the feedstock to use the new recipe.yaml
format.::

    # install conda-smithy
    conda install conda-smithy

    # typically run this in the root of the feedstock
    conda smithy rerender

That took a long time to figure out.  To see all of the existing feedstocks
that have been converted to the new recipe.yaml format, you can use the link
https://github.com/search?q=org%3Aconda-forge+path%3Arecipe.yaml&type=code

Soapbox
=======
Why they didn't have an if statement where recipe/meta.yaml uses conda-build
and recipe/recipe.yaml uses rattler-build is beyond me.  There can only be one
or the other in the recipe directory.