Who am I?

• Filipe Fernandes
• Involved in the IOOS conda channel
• Now deeply involved in the conda-forge community channel

The problem

The Python scientific community always wanted a package manager that is cross platform, does not require sudo, and let's Python be awesome. The conda package manager solved that problem, but created a new ones.

more about the problem

The defaults cannot keep up with the pace of the scientific community and many users/communities channels were created to fill in that gap. That led to duplication of effort, recipe fragmentation, unstable environments when mixing and matching packages from different channels, etc.

Let's take a step back: what is a conda channel?

• Is similar to a Linux repository (or app store)
• The service is hosted for free at Continuum's Anaconda Cloud
• We can upload pre-compiled binaries using the conda package manager

Well... What is a conda?

• An open-source packaging system developed for, and used by, the scientific software community.
• From their own webpage:
• "Package Everything!"
• "And share your repositories with clients or colleagues."

Why use conda?

• Reproducible environments are easy to create
• Better solution than wheels for Python packages that depend on external libraries
• One recipe for multiple platforms (no apt-get, yum, brew, etc)

The solution

The conda-forge organization was created with to be a transparent, open, community led organization, to build conda packages and, hopefully, provide a stable source for packages while reducing the effort duplication and recipe fragmentation.

What do we mean by community?

Having a community-governed package channel for conda and a community process for submitting, verifying, and storing signed project releases

https://conda-forge.github.io/

The conda-forge channel

• 70 contributors
• 474 packages
• Available platforms are: Linux-64, Windows-32/64, and OS X
• You can install with conda install -c conda-forge gdal

Builds

• The recipes are hosted on GitHub
• AppVeyor ➛ Windows
• Travis-CI ➛ OSX
• CircleCI+Docker ➛ Linux

Automation

• The point of entry is staged-recipes
• The tooling lives in conda-smithy
• Once the PR is accepted a GitHub team is created based on the maintainers list
• The maintainers have commit rights only to their own recipes

Linter

Issues

How to use the channel?

conda config --add channels conda-forge

curl -L http://bit.ly/tutorial -o environment.yml

conda env create environment.yml

The tutorial environment file

name: geopython
channels:
    - conda-forge
dependencies:
    - python=2.7
    - jupyter
    - matplotlib
    .
    .
    .

How to contribute?

• Report problems
• Request packages or new releases
• Send PRs adding/fixing packages

Submitting a new recipe

• Fork https://github.com/conda-forge/staged-recipes
• Submit the PR
• The recipe will be built and, once merged, it will trigger the feedstock
• At the feedstock the recipe will be re-built and uploaded to the channel

Creating a recipe

{% set version = "1.0" %}

package:
  name: example
  version: {{ version }}

source:
  fn: example-{{ version }}.tar.gz
  url: https://pypi.python.org/example-{{ version }}.tar.gz
  md5: 842b44f8c95517ed5b792081a2370da1
  patches:
    - some.patch

build:
  number: 0
  script: script: pip install --no-deps .

requirements:
  build:
    - python
    - pip
  run:
    - python

test:
  imports:
    - example
  commands:
    - example --version

about:
  home: https://example.com/examples/
  license: BSD 3-Clause
  summary: An example package

extra:
  recipe-maintainers:
    - GitHubHandle

The truth about creating recipes

• conda skeleton pypi <packages>
• Search, download, copy, and paste

Maintaining recipes in the feedstock

{% set version = "1.0" %}

package:
  name: example
  version: {{ version }}

source:
  fn: example-{{ version }}.tar.gz
  url: https://pypi.python.org/example-{{ version }}.tar.gz
  md5: 842b44f8c95517ed5b792081a2370da1
  patches:
    - some.patch

build:
  number: 0
  .
  .
  .

Maintenance example part 0: the PR

Maintenance example part 1: the actual changes

Maintenance example part 2: provenance

How to find us?

Github

Gitter

Mailing list

Questions?

http://xkcd.com/1629/