Conda Build Templates

[srossross]

Perhaps it would be good to revamp the conda build template files. And make them a first class citizen:

Some ideas:

1. Load templates from meta.yaml.template this should result in a auto generated meta.yaml

   • This would result in better understanding of failed builds becuse of unclear template variables

2. Currently there are two passes of the build: 1 - to fetch the build sources 2. to render the meta.yaml from the template. Perhaps we can make this more clear in the yaml file maybe using the --- yaml syntax

   # File: meta.yaml.template
   # Required information
   # This can not be templated
   source: ...
   --- 
   # Template vars
   build: 
    number: {{ var }}

3. Allow for user contributed build extensions (conda packages) that can define template variables etc. eg:

   # File: meta.yaml.template
   source: ...
   build_ext_modules:
     - conda-build-etx-auto-build-numbers
   ---
   build:
      number: {{ my_great_build_number_generator() }}
   

   in this example conda build . would install/require the conda package conda-build-etx-auto-build-numbers to be installed into the root environment before the build starts.

cc @kalefranz @mcg1969

[srossross]

I started thinking about item 3 when writing a response for Anaconda-Platform/anaconda-server#258

[srossross]

cc @msarahan

[msarahan]

I don't think you need conda-build-ext-modules. I think Jinja2's function definition as filters (http://jinja.pocoo.org/docs/dev/api/#writing-filters) will suffice, and that's something we're working on in #966. There's a nice demo at #848 (comment)

That's number 2 on my priorities, after #953. I think it will probably take me another couple of weeks to get to it.

[srossross]

Thanks @msarahan That solution looks great.

It would also be nice to have reusable extension components, rather than copy the jinja_context.py file from recipe to recipe.

[msarahan]

My hope is that there will be 2 jinja_context.py files: one global, and another per-recipe. Same with the config yaml files. We'll merge these, with the local stuff overriding the global stuff. Conda-build will probably maintain a sane base file - this might be a third, which would be overridden by both the user's global, and the recipe-local.

[github-actions]

Hi there, thank you for your contribution!

This issue has been automatically marked as stale because it has not had recent activity. It will be closed automatically if no further activity occurs.

If you would like this issue to remain open please:

1. Verify that you can still reproduce the issue at hand
2. Comment that the issue is still reproducible and include:
   - What OS and version you reproduced the issue on
   - What steps you followed to reproduce the issue

NOTE: If this issue was closed prematurely, please leave a comment.

Thanks!