snakefmt 0.1.3

The uncompromising Snakemake code formatter

Snakefmt

This repository provides formatting for Snakemake files. It follows the design and specifications of Black.

⚠️WARNING⚠️: snakefmt modifies files in-place by default, thus we strongly recommend ensuring your files are under version control before doing any formatting. This is also to protect you from bugs as the project is still new. You can also pipe the file in from stdin, which will print it to the screen, or use the --diff or --check options. See Usage for more details.

Table of Contents

• Install
  • PyPi
  • Conda
  • Containers
  • Local
• Example File
• Usage
  • Basic Usage
  • Full Usage
• Configuration
• Design
  • Syntax
  • Formatting
• Editor Integration
• Plug Us
• Changes
• Contributing

Install

PyPi

pip install snakefmt

Conda

conda install -c bioconda snakefmt

Containers

Docker

docker pull snakemake/snakefmt
docker run -it snakemake/snakefmt snakefmt --help

You can find all the available tags on the Docker Hub repository.

Singularity

URI="docker://snakemake/snakefmt"
singularity exec "$URI" snakefmt --help

The above will use the latest version. If you want to specify a version then use a tag like so.

VERSION="0.1.3"
URI="docker://snakemake/snakefmt:${VERSION}"

Local

These instructions include installing poetry.

# install poetry
curl -sSL https://raw.githubusercontent.com/python-poetry/poetry/master/get-poetry.py | python3

git clone https://github.com/snakemake/snakefmt && cd snakefmt
# install snakefmt in a new environment
poetry install
# activate the environment so snakefmt is available on your PATH
poetry shell

Example File

Input

from snakemake.utils import min_version
min_version("5.14.0")
configfile: "config.yaml" # snakemake keywords are treated like classes i.e. 2 newlines
SAMPLES = ['s1', 's2'] # strings are normalised
CONDITIONS = ["a", "b", "longlonglonglonglonglonglonglonglonglonglonglonglonglonglonglong"] # long lines are wrapped
include: "rules/foo.smk" # 2 newlines

rule all:
    input: "data/results.txt" # newlines after keywords enforced and trailing comma

rule gets_separated_by_two_newlines:
    input:
        files = expand("long/string/to/data/files/gets_broken_by_black/{sample}.{condition}",sample=SAMPLES, condition=CONDITIONS)
if True:
    rule can_be_inside_python_code:
        input: "parameters", "get_indented"
        threads: 4 # Numeric params stay unindented
        params: key_val = "PEP8_formatted"
        run:

                print("weirdly_spaced_string_gets_respaced")

Output

from snakemake.utils import min_version

min_version("5.14.0")


configfile: "config.yaml" # snakemake keywords are treated like classes i.e. 2 newlines


SAMPLES = ["s1", "s2"] # strings are normalised
CONDITIONS = [
    "a",
    "b",
    "longlonglonglonglonglonglonglonglonglonglonglonglonglonglonglong",
]  # long lines are wrapped


include: "rules/foo.smk" # 2 newlines


rule all:
    input:
        "data/results.txt", # newlines after keywords enforced and trailing comma


rule gets_separated_by_two_newlines:
    input:
        files=expand(
            "long/string/to/data/files/gets_broken_by_black/{sample}.{condition}",
            sample=SAMPLES,
            condition=CONDITIONS,
        ),


if True:

    rule can_be_inside_python_code:
        input:
            "parameters",
            "get_indented",
        threads: 4 # Numeric params stay unindented
        params:
            key_val="PEP8_formatted",
        run:
            print("weirdly_spaced_string_gets_respaced")

Usage

Basic Usage

Format a single Snakefile.

snakefmt Snakefile

Format all Snakefiles within a directory.

snakefmt workflows/

Format a file but write the output to stdout.

snakefmt - < Snakefile

Full Usage

$ snakefmt --help
Usage: snakefmt [OPTIONS] [SRC]...

  The uncompromising Snakemake code formatter.

  SRC specifies directories and files to format. Directories will be
  searched for file names that conform to the include/exclude patterns
  provided.

  Files are modified in-place by default; use diff, check, or  `snakefmt - <
  Snakefile` to avoid this.

Options:
  -l, --line-length INT  Lines longer than INT will be wrapped.  [default: 88]
  --check                Don't write the files back, just return the status.
                         Return code 0 means nothing would change. Return code
                         1 means some files would be reformatted. Return code
                         123 means there was an error.

  -d, --diff             Don't write the files back, just output a diff for
                         each file to stdout.

  --compact-diff         Same as --diff but only shows lines that would change
                         plus a few lines of context.

  --include PATTERN      A regular expression that matches files and
                         directories that should be included on recursive
                         searches.  An empty value means all files are
                         included regardless of the name.  Use forward slashes
                         for directories on all platforms (Windows, too).
                         Exclusions are calculated first, inclusions later.
                         [default: (\.smk$|^Snakefile)]

  --exclude PATTERN      A regular expression that matches files and
                         directories that should be excluded on recursive
                         searches.  An empty value means no paths are
                         excluded. Use forward slashes for directories on all
                         platforms (Windows, too). Exclusions are calculated
                         first, inclusions later.  [default: (\.snakemake|\.eg
                         gs|\.git|\.hg|\.mypy_cache|\.nox|\.tox|\.venv|\.svn|_
                         build|buck-out|build|dist)]

  -c, --config PATH      Read configuration from PATH. By default, will try to
                         read from `./pyproject.toml`

  -h, --help             Show this message and exit.
  -V, --version          Show the version and exit.
  -v, --verbose          Turns on debug-level logging.

Check

--check

Does not write any formatted code back to file. It will instead check whether any changes would be made. It returns one of three possible exit codes:

0 - indicates no changes would be made

$ echo 'include: "foo.txt"' | snakefmt --check -                                        
[INFO] 1 file(s) would be left unchanged 🎉
$ echo "Exit code: $?"
Exit code: 0

1 - indicates changes would be made

$ echo 'include:"foo.txt"' | snakefmt --check - 
[INFO] 1 file(s) would be changed 😬
$ echo "Exit code: $?"
Exit code: 1

123 - indicates there was an error such as invalid syntax

$ echo 'include:' | snakefmt --check -            
[ERROR] L2: In include definition.
[INFO] 1 file(s) contains errors 🤕
$ echo "Exit code: $?"
Exit code: 123

Compact diff

--compact-diff

Does not write any formatted code back to file. It will instead print a compact diff of how the code looks before and after formatting. The diff is compact as it only prints the lines that will change, with a few lines of surrounding context.

$ echo 'x = 1\ny = 3\n\n\nrule foo:\n\tinput: "foo.txt"' | snakefmt --compact-diff -
=====> Diff for stdin <=====

--- original
+++ new
@@ -3,4 +3,5 @@
 
 
 rule foo:
-       input: "foo.txt"
+    input:
+        "foo.txt",

[INFO] All done 🎉

The above example shows that the variable assignments at the beginning of the file are not included in the compact diff (but would be included in a full diff).

Diff

--diff

Does not write any formatted code back to file. It will instead print a diff of how the code looks before and after formatting.

$ echo 'rule foo:\n\tinput: "foo.txt"' | snakefmt --diff -
=====> Diff for stdin <=====

  rule foo:
-       input: "foo.txt"
+     input:
+         "foo.txt",

[INFO] All done 🎉

If multiple files are specified, a diff for each file is written to stdout, separated by =====> Diff for <filepath> <=====.

Configuration

snakefmt is able to read project-specific default values for its command line options from a pyproject.toml file. In addition, it will also load any black configurations you have in the same file.

By default, snakefmt will search in your current directory for a file named pyproject.toml. If your configuration file is located somewhere else or called something different, then specify the location with --config.

Any options you pass on the command line will take precedence over default values in the configuration file.

Example

pyproject.toml

[tool.snakefmt]
line-length = 90
include = '\.smk$|^Snakefile|\.py$'

# snakefmt passes these options on to black
[tool.black]
target-version = ["py37"]

In this example we increase the --line-length value and also include python (*.py) files for formatting - this effectively runs black on them. snakefmt will also pass on the [tool.black] settings, internally, to black.

Design

Syntax

snakefmt's parser will spot syntax errors in your snakefiles:

• Unrecognised keywords
• Duplicate keywords
• Invalid parameters
• Invalid python code

But snakefmt not complaining does not guarantee your file is entirely error-free.

Formatting

Python code is blacked.

Snakemake-specific syntax is formatted following the same principles: see PEP8.

Editor Integration

For instructions on how to integrate snakefmt into your editor of choice, refer to docs/editor_integration.md

Plug Us

If you can't get enough of badges, then feel free to show others you're using snakefmt in your project.

Markdown

[![Code style: snakefmt](https://img.shields.io/badge/code%20style-snakefmt-000000.svg)](https://github.com/snakemake/snakefmt)

ReStructuredText

.. image:: https://img.shields.io/badge/code%20style-snakefmt-000000.svg
    :target: https://github.com/snakemake/snakefmt

Changes

See CHANGELOG.md.

Contributing

Please refer to CONTRIBUTING.md.