A repository for hosting nextflow [`DSL2`](https://www.nextflow.io/docs/edge/dsl2.htmlhttps://www.nextflow.io/docs/edge/dsl2.html) module files and subworkflows containing tool-specific process definitions and their associated documentation.
The DSLv2 features for Nextflow are new for everyone and not just beginners. We discussed some terminology terms to discuss things related to modules & subworkflows more appropriately:
* *Module*: A `process`that can be used between different pipelines, which is atomic (i.e. can/should not be divided further).
* *Subworkflow*: A combined set of modules, that combine a logical step in a pipeline using multiple modules together. Example: A preprocessing subworkflow for FastQ input, that could be (re-) used across multiple pipelines to QC input FastQ files.
* *Workflow*: What DSLv1 users would consider a pipeline, e.g. from input to potentially complex output. Can either consist of individual modules, a large monolithic script as in DSLv1 or a combination of subworkflows (or any combination of these three).
The Nextflow [`include`](https://www.nextflow.io/docs/edge/dsl2.html#modules-include) statement can be used within your pipelines in order to load module files that you have available locally.
You should be able to get a good idea as to how other people are using module files by looking at pipelines available in nf-core e.g. [`nf-core/rnaseq`](https://github.com/nf-core/rnaseq/pull/162)
The module files hosted in this repository define a set of processes for software tools such as `fastqc`, `trimgalore`, `bwa` etc. This allows you to share and add common functionality across multiple pipelines in a modular fashion.
> The definition and standards for module files are still under discussion amongst the community but hopefully, a description should be added here soon!
If you want to use an existing module file available in `nf-core/modules`, and you're running on a system that has no internet connection, you'll need to download the repository (e.g. `git clone https://github.com/nf-core/modules.git`) and place it in a location that is visible to the file system on which you are running the pipeline. Then run the pipeline by creating a custom config file called e.g. `custom_module.conf` containing the following information:
If you decide to upload your module file to `nf-core/modules` then this will ensure that it will be automatically downloaded, and available at run-time to all nf-core pipelines, and to everyone within the Nextflow community! See [`nf-core/modules/nf`](https://github.com/nf-core/modules/tree/master/nf) for examples.
> The definition and standards for module files are still under discussion amongst the community but hopefully, a description should be added here soon!
If you want to add a new module config file to `nf-core/modules` please test that your pipeline of choice runs as expected by using the [`-include`](https://www.nextflow.io/docs/edge/dsl2.html#modules-include) statement with a local version of the module file.
Please add some documentation to the top of the module file in the form of native Nextflow comments. This has to be specified in a particular format as you will be able to see from other examples in the [`nf-core/modules/nf`](https://github.com/nf-core/modules/tree/master/nf) directory.
[Fork](https://help.github.com/articles/fork-a-repo/) the `nf-core/modules` repository to your own GitHub account. Within the local clone of your fork add the module file to the [`nf-core/modules/nf`](https://github.com/nf-core/modules/tree/master/nf) directory. Please keep the naming consistent between the module and documentation files e.g. `bwa.nf` and `bwa.md`, respectively.
Commit and push these changes to your local clone on GitHub, and then [create a pull request](https://help.github.com/articles/creating-a-pull-request-from-a-fork/) on `nf-core/modules` GitHub repo with the appropriate information.
We will be notified automatically when you have created your pull request, and providing that everything adheres to nf-core guidelines we will endeavour to approve your pull request as soon as possible.
