Wave containers

Wave is a container provisioning service integrated with Nextflow. It allows the building, uploading and managing of container images required by your data analysis workflows on-demand, during the pipeline execution in a fully automated manner.

Getting started

Note

This feature requires Nextflow 22.10.0 or later.

Nextflow installation

If you have already installed Nextflow, update to the latest version using this command:

nextflow -self-update

If you don’t have Nextflow already installed, install it with the command below:

curl get.nextflow.io | bash

Wave configuration

Wave can be used in any Nextflow pipeline by adding the following snippet to your nextflow.config file:

wave {
  enabled = true
}

tower {
  accessToken = '<your access token>'
}

Tip

The use of the Tower access token is not mandatory, however, it’s required to enable access to private repositories and it allows higher service rate limits compared to anonymous users.

Use cases

Authenticate private repositories

Wave allows the use of private repositories in your Nextflow pipelines. The repository access keys need to be provided via the Nextflow Tower credentials manager feature.

Once the credentials have been created, you only need to specify your Tower account access token in your pipeline configuration file. If the credentials were created in a Tower organization workspace, specify the workspace ID as well in the config file as shown below:

tower {
  accessToken = '<your access token>'
  workspaceId = '<your workspace id>'
}

Build module containers

Wave can build and provision container images on-demand for your Nextflow pipelines.

To enable this feature, add the Dockerfile of the container to be built in the module directory where the pipeline process is defined. When Wave is enabled, it automatically uses the Dockerfile to build the required container, upload to the registry, and uses the container to carry out the tasks defined in the module.

Tip

Make sure the process does not declare a container directive, otherwise it will take precedence over the Dockerfile definition.

If a process uses a container directive and you still want to build the container using the Dockerfile provided in the module directory, add the following setting to the pipeline config file:

wave.strategy = ['dockerfile','container']

The above line instructs Wave to give the module Dockerfile priority over process container directives.

Warning

Wave currently does not support ADD, COPY and other Dockerfile commands that access files in the host file system.

Build Conda based containers

Wave allows the provisioning of containers based on the conda directive used by the processes in your pipeline. This is a quick alternative to building Conda packages in the local computer. Moreoever, this enables the use of Conda packages in your pipeline when deploying it in cloud-native platforms such as AWS Batch and Kubernetes, which do not allow the (easy) use of the Conda package manager.

Having Wave enabled in your pipeline, there’s nothing else to do other than define the conda requirements in the pipeline processes provided the same process does not also specify a container directive or a Dockerfile.

In the latter case, add the following setting to your pipeline configuration:

wave.strategy = ['conda']

The above setting instructs Wave to only use the conda directive to provision the pipeline containers, ignoring the use of the container directive and any Dockerfile(s).

Push to a private repository

Containers built by Wave are uploaded to the Wave default repository hosted on AWS ECR with name 195996028523.dkr.ecr.eu-west-1.amazonaws.com/wave/build. The images in this repository are automatically deleted after 1 week from the date of their push.

If you want to store Wave containers in your own container repository use the following settings in the Nextflow configuration file:

wave.build.repository = 'example.com/your/build-repo'
wave.build.cacheRepository = 'example.com/your/cache-repo'

The first repository is used to store the built container images. The second one is used to store the individual image layers for caching purposes.

The repository access keys need to be specified using the Tower credentials manager as specified in the Authenticate private repositories section.

Advanced settings

The following configuration options are available:

Name	Description
wave.enabled	Enable/disable the execution of Wave containers
wave.endpoint	The Wave service endpoint (default: https://wave.seqera.io)
wave.build.repository	The container repository where image built by Wave needs to be uploaded (note: the corresponding credentials need to be provided in your Nextflow Tower account).
wave.build.cacheRepository	The container repository used to cache image layers build by the Wave service (note: the corresponding credentials need to be provided in your Nextflow Tower account).
wave.conda.mambaImage	The Mamba container image is used to build Conda based container. This is expected to be micromamba-docker image.
wave.conda.commands	One or more commands to be added to the Dockerfile used by build a Conda based image.
wave.strategy	The strategy to be used when resolving ambiguous Wave container requirement (default: 'container,dockerfile,conda')

More examples

Check out the Wave showcase repository for more examples how to use Wave containers.