Class PortPassThroughSource<TOutput>

A dataflow worker that passes rows from an upstream input port belonging to a different worker (normally residing under a different parent), to the Output port on this worker. This is mainly used when encapsulating a child dataflow worker with an input port (i.e. a transform or target) inside a parent dataflow worker, and passing the parent input port rows to the child input port. This allows using dataflow (and other) workers as building blocks when creating new dataflow workers.

The parent worker can have any number of input and output ports, as well as any number of child workers, and would add a PortPassThroughSource for each port to pass from parent to a child worker, and a PortPassThroughTarget<TInputOutput> for each port to pass from a child worker to the parent. Use both PortPassThroughSource and PortPassThroughTarget to create a parent transform.

Note that the parent must await the completion of the PortPassThroughSource worker before it itself completes, otherwise the parent input port will not be completely emptied and will raise an exception.

Please also see the Compose Target with Pass-through example.

Inheritance
Object
WorkerParent
WorkerBase
WorkerBase<PortPassThroughSource<TOutput>>
PortPassThroughSource<TOutput>
Implements
Inherited Members
Namespace: actionETL
Assembly: actionETL.dll
Syntax
public class PortPassThroughSource<TOutput> : WorkerBase<PortPassThroughSource<TOutput>>, IDisposeOnFinished where TOutput : class
Type Parameters
Name Description
TOutput

The type of each row.

Constructors

PortPassThroughSource(WorkerParent, String, InputPort<TOutput>)

Initializes a new instance of the PortPassThroughSource<TOutput> dataflow worker that pass rows from an upstream input port belonging to a different worker, to the Output port on this worker. This is mainly used when encapsulating a child dataflow worker with an input port (i.e. a transform or target) inside a parent dataflow worker, and passing the parent input port rows to the child input port.

Declaration
public PortPassThroughSource(WorkerParent parentWorker, string workerName, InputPort<TOutput> inputPort)
Parameters
Type Name Description
WorkerParent parentWorker

The parent worker. Cannot be null.
String workerName

Name of the worker.

Set to a prefix plus a trailing "/" (e.g. "MyPrefix-/") to generate a unique name from the prefix plus an increasing number starting at 1.

While less useful, set to null, whitespace or "/" to generate a unique name from the worker type plus an increasing number starting at 1.

The name cannot otherwise contain "/", and cannot start with double underscore "__".

InputPort<TOutput> inputPort

The upstream (non-sibling worker) input port to take rows from.
Exceptions
Type Condition
ArgumentException

workerName:

  • Workers with the same parent must have unique names.
  • Worker and worker system names cannot contain '/' or start with double underscore '__'.
ArgumentNullException

workerParent - All workers must have a parent. The top level workers have the worker system as parent.
InvalidOperationException
  • Cannot add child worker to parent which has completed. Are you adding it to the correct parent?
  • Cannot add worker to parent, since its children have been started. Are you adding it to the correct parent?

Properties

Output

Gets the output port for sending rows to downstream workers.

Declaration
public OutputPort<TOutput> Output { get; }
Property Value
Type Description
OutputPort<TOutput>

PassThroughInput

Gets or sets the input port belonging to a different worker, from which to take and pass-through rows.

Declaration
public InputPort<TOutput> PassThroughInput { get; set; }
Property Value
Type Description
InputPort<TOutput>

The pass-through input port.

Methods

RunAsync()

This method can be overridden to add custom functionality to the derived worker that runs before and after the main processing. In this case, the base class base.RunAsync() must be called for the worker to function correctly.

Typically, this worker is used without overriding this method.

Declaration
protected override async Task<OutcomeStatus> RunAsync()
Returns
Type Description
Task<OutcomeStatus>

A Task describing the success or failure of the worker. An asynchronous async implementation would e.g. return OutcomeStatus.Succeeded on success, while a synchronous implementation would return OutcomeStatus.SucceededTask.
Overrides

Implements