conda-deps 0.0.4

Generate conda environment files from Python source code

Purpose

The goal of conda_deps is to generate a conda environment file as a result of the dependencies found in a repository. At the moment, it only translates Python and R dependencies but it would be great to have it working for other programming languages as well.

conda_deps translates import statements in Python source code like:

import numpy
import scipy

into a conda environment yaml file:

name: testenv

channels:
- conda-forge
- bioconda
- defaults

dependencies:
- python
- numpy
- scipy

For R it translates library imports like:

library(reshape2)
library(ggplot2)

into:

name: testenv

channels:
- conda-forge
- bioconda
- defaults

dependencies:
- r-base
- r-reshape2    
- r-ggplot2

Installation

conda_deps only works in Python 3 and will only scan properly Python 3 source code. There should be no restriction in the case of R.

conda_deps has been uploaded to conda-forge so you can install it with:

# if you don't have conda available:
curl -O https://repo.continuum.io/miniconda/Miniconda3-latest-Linux-x86_64.sh
bash Miniconda3-latest-Linux-x86_64.sh -b -p conda-install
source conda-install/etc/profile.d/conda.sh 
conda update --all --yes

# once conda is available:
conda create --name conda_deps --channel conda-forge conda_deps
conda activate conda_deps
conda_deps --help

Usage

This is how you scan a single Python or R file:

conda_deps </path/to/filename>

The script can also scan folders:

conda_deps </path/to/folder/>

In case you want to exclude one or more subfolders, use the --exclude-folder option one or more times:

conda_deps --exclude-folder </path/to/folder/folder1> </path/to/folder>

You may also want to scan additonal files of folders:

python conda_deps.py </path/to/folder> --include-files my-script.py --include-files </another/folder>

How it works

Python source code

The script uses Python's Abstract Syntax Trees to parse files ending in .py. It looks for import <module> statements, and discards the modules belonging to the Python Standard Library (e.g. import os). It assumes that <module> has a corresponding conda package with the same name (e.g. import numpy corresponds to conda install numpy). However, that is not always the case and you can provide a proper translation between the module name and its corresponding conda package (e.g. import yaml will require conda install pyyaml) via the python_deps.json file, which will be loaded into a dictionary at the beginning of the script. It looks like this:

{
    "Bio":"biopython",
    "Cython":"cython",
    "bs4":"beautifulsoup4",
    "bx":"bx-python",
    "lzo":"python-lzo",
    "pyBigWig":"pybigwig",
    "sklearn":"scikit-learn",
    "web":"web.py",
    "weblogolib":"python-weblogo",
    "yaml":"pyyaml"
}    

The dictionary key is the name in import <module> and the value is the name of the conda package.

The python_deps.json file is meant to be useful for generic use. However, it is possible to include additional json files specific to your project:

conda_deps --include-py-json my_project.json </path/to/project/>

The translations in my_project.json will take priority over those in python_deps.json.

If you find that there are missing translations in the general purpose python_deps.json file, please feel free to open a pull request to add more.

R source code

In the case of R files, it uses grep to look for library(name) regular expressions in files ending in .R. The same way we use a json file to detail translations for Python, we use the r_deps.json file which will be loaded into a dictionary at the beginning of the script. Here is how it looks like:

{
    "dplyr":"r-dplyr",
    "edgeR":"bioconductor-edger",
    "flashClust":"r-flashclust",
    "gcrma":"bioconductor-gcrma",
    "ggplot2":"r-ggplot2",
    "gplots":"r-gplots",
    "gridExtra":"r-gridextra",
    "grid":"r-gridbase",
    "gtools":"r-gtools",
    "hpar":"bioconductor-hpar",
    "knitr":"r-knitr",
    "limma":"bioconductor-limma",
    "maSigPro":"bioconductor-masigpro",
}

In this case the dictionary key is the name in library(name) and the value is the name of the conda package.

If you are missing a translation in r_deps.json you can either open a pull request to add it or include it in your own json file:

conda_deps --include-r-json my_project.json </path/to/project/>

Please note that the translations in my_project.json will take priority over those in r_deps.json.

Related tools

• snakefood: a more comprehensive tool but it works only with Python 2.
• pipreqs: does a similar job but for requirements.txt files and pip.

References

• https://docs.python.org/3/library/ast.html#module-ast
• http://bit.ly/2rDf5xu
• http://bit.ly/2r0Uv9t
• https://github.com/titusjan/astviewer