Using a Subflow as a Source

You can use a subflow as the first stage in a flow to read data from a source and even perform some processing on the data before passing it to the parent flow. You can create a subflow that is as simple as a single source stage that is configured in a way that you want to reuse in multiple flows, or you could create a more complex subflow that reads data then processes it in some way before passing it to the parent flow.

In Spectrum Enterprise Designer, click File > New > Dataflow > Subflow.
Drag the appropriate data source from the palette to the canvas and configure it.

For example, if you want the subflow to read data from a comma-separated file, you would drag a Read from File stage to the canvas.
If you want the subflow to process the data in some way before sending it to the parent flow, add additional stages as needed to perform the preprocessing you want.
At the end of the flow, add an Output stage and configure it.

This allows the data from the subflow to be sent to the parent flow.

For example, if you created a subflow that reads data from a file then uses a Transformer stage to trim white space and standardize the casing of a field, you would have a subflow that looks like this:
Double-click the Output stage and select the fields you want to pass into the parent flow.
Select File > Save and save the subflow.
Select File > Expose to make the subflow available to include in flows.
In the flow where you want to include the subflow, drag the subflow from the palette to the canvas.
Connect the subflow to the flow stage you want.

Note: Since the subflow contains a source stage rather than an Input stage, the subflow icon only has an output port. It can only be used as a source in the flow.

The parent flow now uses the subflow you created as input. For example, if you created a subflow named "Read from File and Transform" and you add the subflow and connect it to a Broadcaster stage, your flow would look like this: