Nextflow

ICA supports running pipelines defined using Nextflow. See this tutorial for an example.

In order to run Nextflow pipelines, the following process-level attributes within the Nextflow definition must be considered.

System Information

Info
Details

Nextflow version

20.10.0, 22.04.3 (default)

Executor

Kubernetes

Nextflow Version

You can select the Nextflow version while building a pipeline as follows:

interface

GUI

Select the Nextflow version at Projects > your_project > flow > pipelines > your_pipeline > Details tab.

API

Select the Nextflow version by setting it in the optional field "pipelineLanguageVersionId". When not set, a default Nextflow version will be used for the pipeline.

Compute Node

For each compute type, you can choose between the scheduler.illumina.com/lifecycle: standard (default - AWS on-demand) or scheduler.illumina.com/lifecycle: economy (AWS spot instance) tiers.

Compute Type

To specify a compute type for a Nextflow process, use the pod directive within each process. Set the annotation to scheduler.illumina.com/presetSize and the value to the desired compute type. A list of available compute types can be found here. The default compute type, when this directive is not specified, is standard-small (2 CPUs and 8 GB of memory).

pod annotation: 'scheduler.illumina.com/presetSize', value: 'fpga-medium'

Inputs

Inputs are specified via the XML input form or JSON-based input form. The specified code in the XML will correspond to the field in the params object that is available in the workflow. Refer to the tutorial for an example.

Outputs

Outputs for Nextflow pipelines are uploaded from the out directory in the attached shared filesystem. The publishDir directive can be used to symlink (recommended), copy or move data to the correct folder. Data will be uploaded to the ICA project after the pipeline execution completes.

publishDir 'out', mode: 'symlink'

Nextflow Configuration

During execution, the Nextflow pipeline runner determines the environment settings based on values passed via the command-line or via a configuration file (see Nextflow Configuration documentation). When creating a Nextflow pipeline, use the nextflow.config tab in the UI (or API) to specify a nextflow configuration file to be used when launching the pipeline.

Syntax highlighting is determined by the file type, but you can select alternative syntax highlighting with the drop-down selection list.

The following configuration settings will be ignored if provided as they are overridden by the system:

executor.name
executor.queueSize
k8s.namespace
k8s.serviceAccount
k8s.launchDir
k8s.projectDir
k8s.workDir
k8s.storageClaimName
k8s.storageMountPath
trace.enabled
trace.file
trace.fields
timeline.enabled
timeline.file
report.enabled
report.file
dag.enabled
dag.file

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