A documentation string for this object, or an array of strings which should be concatenated.
Declares hints applying to either the runtime environment or the workflow engine that may be helpful in executing this workflow step. It is not an error if an implementation cannot satisfy all hints, however the implementation may report a warning.
The unique identifier for this object.
Defines the input parameters of the workflow step. The process is ready to run when all required input parameters are associated with concrete values. Input parameters include a schema for each parameter which is used to validate the input object. It may also be used build a user interface for constructing the input object.
A short, human-readable label of this object.
Defines the parameters representing the output of the process. May be used to generate and/or validate the output object.
Declares requirements that apply to either the runtime environment or the workflow engine that must be met in order to execute this workflow step. If an implementation cannot satisfy all requirements, or a requirement is listed which is not recognized by the implementation, it is a fatal error and the implementation must not attempt to run the process, unless overridden at user option.
Specifies the process to run.
Required if scatter is an array of more than one element.
If defined, only run the step when the expression evaluates to
true. If false the step is skipped. A skipped step
produces a null on each output.
Document fragment to load this record object from.
Base URI to generate child document IDs against.
Context for loading URIs and populating objects.
ID at this position in the document (if available)
Generated using TypeDoc
Auto-generated class implementation for https://w3id.org/cwl/cwl#WorkflowStep
A workflow step is an executable element of a workflow. It specifies the underlying process implementation (such as
CommandLineToolor anotherWorkflow) in therunfield and connects the input and output parameters of the underlying process to workflow parameters.Scatter/gather
To use scatter/gather, ScatterFeatureRequirement must be specified in the workflow or workflow step requirements.
A "scatter" operation specifies that the associated workflow step or subworkflow should execute separately over a list of input elements. Each job making up a scatter operation is independent and may be executed concurrently.
The
scatterfield specifies one or more input parameters which will be scattered. An input parameter may be listed more than once. The declared type of each input parameter is implicitly becomes an array of items of the input parameter type. If a parameter is listed more than once, it becomes a nested array. As a result, upstream parameters which are connected to scattered parameters must be arrays.All output parameter types are also implicitly wrapped in arrays. Each job in the scatter results in an entry in the output array.
If any scattered parameter runtime value is an empty array, all outputs are set to empty arrays and no work is done for the step, according to applicable scattering rules.
If
scatterdeclares more than one input parameter,scatterMethoddescribes how to decompose the input into a discrete set of jobs.dotproduct specifies that each of the input arrays are aligned and one element taken from each array to construct each job. It is an error if all input arrays are not the same length.
nested_crossproduct specifies the Cartesian product of the inputs, producing a job for every combination of the scattered inputs. The output must be nested arrays for each level of scattering, in the order that the input arrays are listed in the
scatterfield.flat_crossproduct specifies the Cartesian product of the inputs, producing a job for every combination of the scattered inputs. The output arrays must be flattened to a single level, but otherwise listed in the order that the input arrays are listed in the
scatterfield.Conditional execution (Optional)
Conditional execution makes execution of a step conditional on an expression. A step that is not executed is "skipped". A skipped step produces
nullfor all output parameters.The condition is evaluated after
scatter, using the input object of each individual scatter job. This means over a set of scatter jobs, some may be executed and some may be skipped. When the results are gathered, skipped steps must benullin the output arrays.The
whenfield controls conditional execution. This is an expression that must be evaluated withinputsbound to the step input object (or individual scatter job), and returns a boolean value. It is an error if this expression returns a value other thantrueorfalse.Conditionals in CWL are an optional feature and are not required to be implemented by all consumers of CWL documents. An implementation that does not support conditionals must return a fatal error when attempting execute a workflow that uses conditional constructs the implementation does not support.
Subworkflows
To specify a nested workflow as part of a workflow step, SubworkflowFeatureRequirement must be specified in the workflow or workflow step requirements.
It is a fatal error if a workflow directly or indirectly invokes itself as a subworkflow (recursive workflows are not allowed).