Crimson converts non-standard bioinformatics tool outputs to JSON or YAML.
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You can also use your local clone with git send-email.


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crimson converts non-standard bioinformatics tool outputs to JSON or YAML.

Currently it can convert outputs of the following tools:

The conversion can be done using the command line interface or by calling the tool-specificparser functions in your Python script.


crimson is available on the Python Package Index and you can install it via pip:

$ pip install crimson

It is also available on BioConda, both through the conda package manager or as a Docker container.


#As a command line tool

The general command is crimson {program_name} and by default the output is written to stdout. For example, to use the picard parser, you would execute:

$ crimson picard /path/to/a/picard.metrics

You can also specify a file name directly to write to a file. The following command will write the output to a file named converted.json:

$ crimson picard /path/to/a/picard.metrics converted.json

Some parsers may also accept additional input format. The FastQC parser, for example, also works if you specify a path to a FastQC output directory:

$ crimson fastqc /path/to/a/fastqc/dir

or path to a zipped result:

$ crimson fastqc /path/to/a/fastqc_result.zip

When in doubt, use the --help flag:

$ crimson --help            # for the general help
$ crimson fastqc --help     # for parser-specific (FastQC) help

#As a Python library function

Generally, the function to import is located at crimson.{program_name}.parser. For example, to use the picard parser in your script, you can do:

from crimson import picard

# You can specify the input file name as a string ...
parsed = picard.parse("/path/to/a/picard.metrics")

# ... or a file handle
with open("/path/to/a/picard.metrics") as src:
    parsed = picard.parse(src)


  • Not enough tools use standard output formats.
  • Writing and re-writing the same parsers across different scripts is not a productive way to spend the day.

#Local Development

Setting up a local development requires that you set up all of the supported Python versions. We recommend using pyenv for this.

The following steps can be your guide for your local development setup:

# Clone the repository and cd into it.
$ git clone https://git.sr.ht/~bow/crimson
$ cd crimson

# Create your virtualenv.
# If you already have pyenv installed, you may use the Makefile rule below.
$ make dev-pyenv

# Install the package along with its development dependencies.
$ make dev

# Run the test and linter suite to verify the setup.
$ make lint test


If you are interested, crimson accepts the following types contribution:

  • Documentation additions (if anything seems unclear, feel free to open an issue)
  • Bug reports
  • Support for tools' outputs which can be converted to JSON or YAML.

For any of these, feel free to open an issue in the issue tracker or submit a pull request.


crimson is BSD-licensed. Refer to the LICENSE file for the full license.