nf-quilt

Nextflow plugin for reading and writing Quilt packages

nf-quilt is a Nextflow plugin developed by Quilt Data, Inc. that enables you read and write directly to Quilt packages wherever your Nextflow pipeline currently uses s3 URIs. It works with any Amazon S3-compatible object store, as long as you have the appropriate credentials.

Quilt packages are versioned, immutable, and shareable data containers that store data, metadata, and documentation as a single atomic unit. They are accessible even by non-technical users via the Quilt Platfrom, a graphical web catalog which runs either in your private AWS cloud or on open.quiltdata.com.

Writing to Quilt Packages

For example, if your current pipeline writes to an S3 bucket specified by the environment variable $WRITE_BUCKET:

nextflow run nf-core/rnaseq --outdir "s3://$WRITE_BUCKET/nf_quilt/rnaseq"

All you have to do is add the nf-quilt plugin to your command line:

nextflow run nf-core/rnaseq -plugins nf-quilt --outdir "s3://$WRITE_BUCKET/nf_quilt/rnaseq"

This will automatically create a nicely-formmated Quilt package with all the metadata from that run.

Use nextflow.config to configure the plugin

To avoid having to manually specify the plugin, you can add it to your nextflow.config file:

plugins {
    id 'nf-quilt'
}

This also works with Nextflow Tower, where you can add the plugin to the "Advanced Options -> Nextflow config file".

As of v0.9+, you can also add a quilt section to your nextflow.config file to specify the metadata and other plugin behaviors:

quilt {
    catalog = 'open.quiltdata.com'
    force = false  // replace (instead of update) existing packages
    meta = [pipeline: 'nf-core/rnaseq']
}

See "Configuration" below for more details.

Working With Quilt+ URIs (Optional)

When using the nf-quilt plugin, you can use Quilt+ URIs (instead of S3 URIs) to specify the package you want to read or write. For example, the URI for the package created from the initial example would be:

quilt+s3://$WRITE_BUCKET#package=nf_quilt/rnaseq

Input URIs

Versioned Quilt+ URIs can be used as input URIs in your Nextflow pipeline, to ensure you know precisely which data you are using. For example, this is a specific version of the output from nf-core/sarek:

quilt+s3://$READ_BUCKET#package=nf-core/sarek@8a2164f48be8e0d6385f64b76b74a8543e9fb1b12a8eff6daeaffa653d52fcf7

If are using the Quilt Platform, you can find the Quilt+ URI for a package in the <> CODE | URI section at the top of the package page.

Output URIs

You can specify a Quilt+ URI as the --outdir parameter in your Nextflow pipeline if you want to specify the package name and metadata for the output, but don't care about the precise location in S3. For example:

nextflow run nf-core/rnaseq --outdir "quilt+s3://$WRITE_BUCKET?key=value#package=nf_quilt/rnaseq"

The key=value part is optional, and can be used to specify metadata for the package, which will be added to the metadata automatically generated by the plugin. This is particularly when working with Quilt workflows, which require specific metadata to be present before a package can be created.

CLI Usage

If your workflow supports --input and --outdir parameters, you can use them to specify the Quilt+ URIs. For example:

nextflow run main.nf --input "quilt+s3://$READ_BUCKET#package=nf-core/sarek@8a2164f48be8e0d6385f64b76b74a8543e9fb1b12a8eff6daeaffa653d52fcf7" --outdir "quilt+s3://$WRITE_BUCKET?key=value#package=test/my-sarek-processor"

Note that you need to quote the URIs to prevent the shell from interpreting the ? and # characters.

Configurations

There are a number of additional parameters you can set in order to customize the behavior of the plugin:

• catalog: specify the DNS hostname of the Quilt catalog to use (default: open.quiltdata.com)
• force: completely replace the existing package, rather than updating it (default: false)
• meta: specify a map of metadata to add to the package (default: {})
• msg: specify the commit message template to use when saving the package
• pkg: specify the name of the package to read or write, when using an S3 URI (default: the first two path components)
• readme: specify a template string for the package README_NF_QUILT.md file
• workflow: specify the name of a Quilt workflow on that bucket to use for metadata validation (default: None)

NOTE: These configurations were previously specified as part of the Quilt+ URI. That functionality has been deprecated, and may be removed in a future release.

Template Strings

Version 0.3.4 and later allow you to customize both the msg and readme via template strings that use these ${variables}:

• cmd: the current command line
• meta: the complete metadata
• msg: the current commit message
• nextflow: the current Nextflow configuration
• now: the ISO 8601 date and time
• pkg: the package name

Note that the full meta is usually extremely large. You should use conditional keys to extract only the metadata you need, if present. For example:

quilt {
    meta = [pipeline: 'nf-core/rnaseq']
    msg = "${meta['config']?.get('runName')}: ${meta['cmd']}"
    readme = '''
# ${pkg}

## ${now}

## Run Command

${cmd}

### Workflow

- **workflow run name**: ```${meta['workflow']?.get('runName')}```
- **scriptFile**: ```${meta['workflow']?.get('scriptFile')}```
- **sessionI**: ```${meta['workflow']?.get('sessionId')}```
- **start**: ```${meta['time_start']}```
- **complete**: ```${meta['time_complete']}```

### Nextflow

${nextflow}

### Processes

`${meta['workflow']?.get('stats')?.getAt('processes')}`
    '''
}