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Contains classes and helpers to build a workflow, and provide options to convert to CWL / WDL

Project description

Janis (janis-pipelines) (Alpha)

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Janis is a framework creating specialised, simple workflow definitions that are then transpiled to
Common Workflow Language or Workflow Definition Language.

Documentation is available here:


WARNING: this project is work-in-progress and is provided as-is without warranty of any kind. There may be breaking changes committed to this repository without notice.

Janis gives you an API to build computational workflows and will generate a workflow description in CWL (v1.2) and WDL (version development). By using Janis, you get type-safety, portability and reproducibility across all of your execution environments.

Janis requires a Python installation > 3.6, and can be installed through PIP (project page):

# Install janis and the toolkits
pip3 install janis-pipelines 

There are two ways to use Janis:

  • Build workflows (and translate to CWL / WDL)
  • Run tools or workflows with CWLTool or Cromwell

Latest versions

Check the table below for the latest released versions of Janis (janis -v):

Repository Version
Janis PyPI version
janis-assistant PyPI version
janis-bioinformatics PyPI version
janis-core PyPI version
janis-pipelines PyPI version
janis-templates PyPI version
janis-unix PyPI version

Example workflow

Let's construct a simple example that takes a string input, calls the echo tool and exposes the Echo tool's output as a workflow output.

# write the workflow to ``
cat <<EOT >>
import janis as j
from import Echo

w = j.WorkflowBuilder("hello_world")

w.input("input_to_print", j.String)
w.step("echo", Echo(inp=w.input_to_print))
w.output("echo_out", source=w.echo.out)

# Translate workflow to WDL
janis translate wdl

# Run the workflow
janis run -o helloworld-tutorial --input_to_print "Hello, World!"

# See your output
cat helloworld-tutorial/echo_out
# Hello, World!

How to use Janis


In addition, there are fully self-guided workshops that more broadly go through the functionality of Janis:


Sometimes it's easier to learn by examples, here are a few hand picked examples:


There are two toolboxes currently available on Janis:


Further information: About

This project was produced as part of the Portable Pipelines Project in partnership with:


Through conference or talks, this project has been referenced by the following titles:

  • Walter and Eliza Hall Institute Talk (WEHI) 2019: Portable Pipelines Project: Developing reproducible bioinformatics pipelines with standardised workflow languages
  • Bioinformatics Open Source Conference (BOSC) 2019: Janis: an open source tool to machine generate type-safe CWL and WDL workflows
  • Victorian Cancer Bioinformatics Symposium (VCBS) 2019: Developing portable variant calling pipelines with Janis
  • GIW / ABACBS 2019: Janis: A Python framework for Portable Pipelines
  • Australian BioCommons, December 2019: Portable pipelines: build once and run everywhere with Janis


v0.9.0 Backwards Compatability

NOTE: Version 0.9.0 brings changes to output directories and camel case changes

  • Janis watch will be incompatible with previously run workflows
  • Your configs might break, as previous versions of janis were not cautious about camel case.
  • Your templates might not work with unrecognised keys (try changing them to camel case instead)
  • Changes to BamBai indexes, format is now .bam.bai

See the CHANGELOG for more information.


Further information: Development

To get help with Janis, please ask a question on Gitter or raise an issue on GitHub.

If you find an issue with the tool definitions, please see the relevant issue page:

This project is work-in-progress and is still in developments. Although we welcome contributions, due to the immature state of this project we recommend raising issues through the Github issues page for Pipeline related issues.

Information about the project structure and more on contributing can be found within the documentation.

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