Picky for Conda documentation¶

Note

This project is not currently maintained and conda-lock is suggested as an alternative.

Picky is a tool for making sure that the packages you have installed in a conda environment match those you have specified.

The recommended workflow is to have an environment.yaml that contains your abstract requirements and an environment.lock.yaml that contains your concrete requirements.

An abstract set of requirements contains the minimal amount of information to install all the packages your projects needs and any maximum or minimum version requirements there may be. For example:

channels:
  - conda-forge
  - defaults
dependencies:
  - python=3
  - pandas < 0.19
  - pip:
    - testfixtures >= 6.0.0

Concrete requirements contain all the detail needed to exactly reproduce the current environment. Given the abstract requirements above, concrete requirements would look something like:

name: myproject
channels:
  - conda-forge
  - defaults
dependencies:
  - appnope=0.1.0=py27hb466136_0
  - numpy=1.11.3=py27h8a80b8c_4
  - pandas=0.18.1=np111py27_0
  ...
  - pip:
    - testfixtures==6.0.1

So, the rough workflow of a project starting from scratch would be:

conda create -n yourproject -c simplistix python=X.Y picky-conda
Add abstract dependencies, including your major Python version and picky-conda, along with any packages that need to be installed with pip, to environment.yaml. After each modification of environment.yaml, run conda env update as follows:
```
$ conda env update --file environment.yaml
```
If you use conda install or pip install to install packages, you will need to remember to add those packages to your environment.yaml afterwards.
When you want to release to production or share your environment with other developers, lock your current exact dependencies with:
```
$ picky lock
```
The resultant environment.lock.yaml should be version controlled.
When setting up the environment elsewhere, the concrete requirements should be used:
```
$ conda env create --force --file environment.lock.yaml
```
If this is as part of an automated testing process, you should also do the following once the environment is set up to make sure there are no unpinned dependencies:
```
$ picky check
```

Configuring Picky¶

Picky can be configured by placing a file called picky.yaml in the same directory as your environment.yaml. Example content could be:

detail: version
develop:
  mypackage: .
ignore:
  # mac-only:
  - appnope

Each of the sections is optional and explained below.

Lock Detail Level¶

The build part of a conda version is the bit after the second = and is specific to the target operating system. If your environment.lock.yaml will be used on multiple operating systems, you can exclude the build part of versions by placing detail: version in your picky.yaml.

If this is done, your concrete requirements will end up looking like the following:

name: myproject
channels:
  - conda-forge
  - defaults
dependencies:
  - appnope=0.1.0
  - numpy=1.11.3
  - pandas=0.18.1
  ...
  - pip:
    - testfixtures==6.0.1

Ignoring Packages¶

Some packages are only installed on a particular operating system. conda env does not currently support operating-specific dependencies. To work around this, you can include package names in the ignore section of picky.yaml and they will not be included in any generated environment.lock.yaml.

If the sample picky.yaml was used, then the resultant concrete requirements produced by picky lock would be:

name: myproject
channels:
  - conda-forge
  - defaults
dependencies:
  - numpy=1.11.3
  - pandas=0.18.1
  ...
  - pip:
    - testfixtures==6.0.1

Note the absence of the appnope package.

Installing Packages with pip in Development Mode¶

It’s often handy to install an application’s source using pip install -e in order to get python packages importable and console scripts set up. However, conda env export currently reports packages installed in this way incorrectly.

To help with all this, you can include a mapping of packages to be installed in this way to their paths on disk in picky.yaml and will use that to create appropriate entries in your environment.lock.yaml.