Common Workflow Language integration with Arvados » History » Version 6

Peter Amstutz, 08/08/2016 03:58 PM

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h1. Common Workflow Language integration with Arvados
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The main integration is @arvados-cwl-runner@.  This tool is used both as a client to submit a job to run the workflow (@arvados-cwl-runner --submit@) and for running the workflow directly (@arvados-cwl-runner --local@).  When the user starts a CWL workflow from workbench, it functions similar to @--submit@ mode.
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Because submit mode works by creating a "runner" job whose purpose is to manage execution of the workflow, it requires an @arvados/jobs@ Docker image with an up-to-date @arvados-cwl-runner@.
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When running a workflow:
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# The user submits a workflow by running @arvados-cwl-runner@ or through workbench, this creates an "workflow job"
# The workflow job is dispatched to a compute node (Compute1)
# The workflow job runs @arvados-cwl-runner@ in a @arvados/jobs@ Docker container with the associated CWL workflow and workflow inputs as job inputs
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# The runner job is responsible for actually executing the workflow:
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## Create a job for each workflow step 
## Submit the job to API server (Job A)
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## Wait for the job to complete
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## Get the output collection for the job (Output A)
## Compute the resulting CWL output object for the workflow step (Result A)
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## Iterate over the workflow until all steps have been executed and final workflow output is available
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# Return the final workflow result
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