Get package version for conda meta.yaml from source file

Question

I\'m trying to reorganize my python package versioning so I only have to update the version in one place, preferably a python module or a text file. For all the places I nee

Answer 1

There are lots of ways to get to your endpoint. Here's what conda itself does...

The source of truth for conda's version information is __version__ in conda/__init__.py. It can be loaded programmatically within python code as from conda import __version__ as you suggest. It's also hard-wired into setup.py here (note this code too), so from the command line python setup.py --version is the canonical way to get that information.

In 1.x versions of conda-build, putting a line

$PYTHON setup.py --version > __conda_version__.txt

in build.sh would set the version for the built package using our source of truth. The __conda_version__.txt file is deprecated, however, and it will likely be removed with the release of conda-build 2.0. In recent versions of conda-build, the preferred way to do this is to use load_setup_py_data() within a jinja2 context, which will give you access to all the metadata from setup.py. Specifically, in the meta.yaml file, we'd have something like this

package:
  name: conda
  version: "{{ load_setup_py_data().version }}"

---

Now, how the __version__ variable is set in conda/__init__.py...

What you see in the source code is a call to the auxlib.packaging.get_version() function. This function does the following in order

1. look first for a file conda/.version, and if found return the contents as the version identifier
2. look next for a VERSION environment variable, and if set return the value as the version identifier
3. look last at the git describe --tags output, and return a version identifier if possible (must have git installed, must be a git repo, etc etc)
4. if none of the above yield a version identifier, return None

Now there's just one more final trick. In conda's setup.py file, we set cmdclass for build_py and sdist to those provided by auxlib.packaging. Basically we have

from auxlib import packaging
setup(
    cmdclass={
        'build_py': packaging.BuildPyCommand,
        'sdist': packaging.SDistCommand,
    }
)

These special command classes actually modify the conda/__init__.py file in built/installed packages so the __version__ variable is hard-coded to a string literal, and doesn't use the auxlib.packaging.get_version() function.

---

In your case, with not wanting to tag every release, you could use all of the above, and from the command line set the version using a VERSION environment variable. Something like

VERSION=1.0.0alpha1 conda build conda.recipe

In your build section meta.yaml recipe, you'll need add a script_env key to tell conda-build to pass the VERSION environment variable all the way through to the build environment.

build:
  script_env:
    - VERSION