tag

The tag directive defines a custom identifier for each task execution. For example:

process hello {
    tag "$code"

    input:
    val code

    script:
    """
    echo $code
    """
}

workflow {
    ch_codes = channel.of('alpha', 'gamma', 'omega')
    hello(ch_codes)
}

The above example logs each task with its corresponding tag:

[6e/28919b] Submitted process > hello (alpha)
[d2/1c6175] Submitted process > hello (gamma)
[1c/3ef220] Submitted process > hello (omega)

Tags are a useful way to track related tasks in a pipeline run. Tasks can be identified by tag in the execution log and the trace report.

note

The name of a task in both reports and lineage is defined as <process> (<tag>).

note

The tag directive is not related to the label directive. Process labels are only used for shared process configuration, not for tracking.