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.
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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:
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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:
