The Nextflow [`-c`](https://www.nextflow.io/docs/latest/config.html) parameter can be used with nf-core pipelines in order to load custom config files that you have available locally.
However, if you or other people within your organisation are likely to be running nf-core pipelines regularly it may be a good idea to use/create a custom config file that defines some generic settings unique to the computing environment within your organisation.
The config files hosted in this repository define a set of parameters which are specific to compute environments at different Institutions but generic enough to be used with all nf-core pipelines.
All nf-core pipelines inherit the functionality provided by Nextflow, and as such custom config files can contain parameters/definitions that are available to both.
For example, if you have the ability to use [Singularity](https://sylabs.io/singularity/) on your HPC you can add and customize the Nextflow [`singularity`](https://www.nextflow.io/docs/latest/config.html#scope-singularity) scope in your config file.
Similarly, you can define a Nextflow [`executor`](https://www.nextflow.io/docs/latest/executor.html) depending on the job submission process available on your cluster.
In contrast, the `params` section in your custom config file will typically define parameters that are specific to nf-core pipelines.
You should be able to get a good idea as to how other people are customising the execution of their nf-core pipelines by looking at some of the config files in [`nf-core/configs`](https://github.com/nf-core/configs/tree/master/conf).
If you want to use an existing config available in `nf-core/configs`, and you're running on a system that has no internet connection, you'll need to download the config file and place it in a location that is visible to the file system on which you are running the pipeline.
Then run the pipeline with `--custom_config_base` or `params.custom_config_base` set to the location of the directory containing the repository files:
Alternatively, instead of using the configuration profiles from this repository, you can run your pipeline directly calling the single institutional config file that you need with the `-c` parameter.
> Note that the nf-core/tools helper package has a `download` command to download all required pipeline files + singularity containers + institutional configs in one go for you, to make this process easier.
If you decide to upload your custom config file to `nf-core/configs` then this will ensure that your custom config file will be automatically downloaded, and available at run-time to all nf-core pipelines, and to everyone within your organisation.
You will simply have to specify `-profile <config_name>` in the command used to run the pipeline.
See [`nf-core/configs`](https://github.com/nf-core/configs/tree/master/conf) for examples.
Please also make sure to add an extra `params` section with `params.config_profile_description`, `params.config_profile_contact` and `params.config_profile_url` set to reasonable values.
Users will get information on who wrote the configuration profile then when executing a nf-core pipeline and can report back if there are things missing for example.
If the user's hostname contains this string at the start of a run or when a run fails and their profile does not contain the profile name, a warning message will be printed.
If you want to add a new custom config file to `nf-core/configs` please test that your pipeline of choice runs as expected by using the [`-c`](https://www.nextflow.io/docs/latest/config.html) parameter.
You will have to create a [Markdown document](https://www.markdownguide.org/getting-started/) outlining the details required to use the custom config file within your organisation.
You might orientate yourself using the [Template](docs/template.md) that we provide and filling out the information for your cluster there.
[Fork](https://help.github.com/articles/fork-a-repo/) the [`nf-core/configs`](https://github.com/nf-core/configs/) repository to your own GitHub account.
Within the local clone of your fork add the custom config file to the [`conf/`](https://github.com/nf-core/configs/tree/master/conf) directory, and the documentation file to the [`docs/`](https://github.com/nf-core/configs/tree/master/docs) directory.
You will also need to edit and add your custom profile to the [`nfcore_custom.config`](https://github.com/nf-core/configs/blob/master/nfcore_custom.config) file in the top-level directory of the clone.
You will also need to edit and add your custom profile to the [`README.md`](https://github.com/nf-core/configs/blob/master/README.md) file in the top-level directory of the clone.
In order to ensure that the config file is tested automatically with GitHub Actions please add your profile name to the `profile:` scope in [`.github/workflows/main.yml`](.github/workflows/main.yml). If you forget to do this the tests will fail with the error:
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 the `nf-core/configs` 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.
Institutional configs work because the pipeline `nextflow.config` file loads the [`nf-core/configs/nfcore_custom.config` config file](https://github.com/nf-core/configs/blob/master/nfcore_custom.config), which in turn loads the institutional configuration file based on the profile `<PROFILE>` supplied on the command line.
To add in pipeline-specific institutional configs, we add a second `includeConfig` call in the pipeline `nextflow.config` file, which loads the `pipeline/<PIPELINE>.config` file from the [`nf-core/configs`](https://github.com/nf-core/configs) repo.
This file has `<PIPELINE>` specific institution configuration again with different profiles `<PROFILE>`.
The pipeline `nextflow.config` file should first load the generic institutional configuration file and then the pipeline-specific institutional configuration file.
Within the local clone of your fork, if not already present, add the following to `nextflow.config`**after** the code that loads the generic nf-core/configs config file:
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 the `nf-core/<PIPELINE>` 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.
[Fork](https://help.github.com/articles/fork-a-repo/) the [`nf-core/configs`](https://github.com/nf-core/configs/) repository to your own GitHub account.
And add or edit the following files in the local clone of your fork.
Make sure to add an extra `params` section with `params.config_profile_description`, `params.config_profile_contact` to the top of `pipeline/<PIPELINE>.config` and set to reasonable values.
Users will get information on who wrote the pipeline-specific configuration profile then when executing the nf-core pipeline and can report back if there are things missing for example.
Add the documentation file to the `docs/pipeline/<PIPELINE>/` directory.
You will also need to edit and add your custom profile to the [`README.md`](https://github.com/nf-core/configs/blob/master/README.md) file in the top-level directory of the clone.
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 the `nf-core/configs` GitHub repo with the appropriate information.
