ext

The ext directive defines user-defined properties.

Usage

For example:

process star {
    container "biocontainers/star:${task.ext.version}"

    input:
    path genome
    tuple val(sampleId), path(reads)

    script:
    """
    STAR --genomeDir $genome --readFilesIn $reads ${task.ext.args ?: ''}
    """
}

In this example, the process container version is controlled by ext.version, and the script supports additional command line arguments through ext.args.

The ext directive can be set in the process definition:

process hello {
    ext version: '2.5.3', args: '--alpha --beta'

    // ...
}

You can also set it in the Nextflow configuration:

process.ext.version = '2.5.3'
process.ext.args = '--alpha --beta'