Hands-On Software Engineering with Golang

Implementing the input source worker

In order to begin a new pipeline run, users are expected to provide an input source that generates the application-specific payloads that drive the pipeline. All user-defined input sources must implement the Source interface, whose definition is as follows:

type Source interface {
    Next(context.Context) bool
    Payload() Payload
    Error() error
}

The Source interface contains the standard set of methods that you would expect for any data source that supports iteration:

• Next attempts to advance the iterator. It returns false if either no more data is available or an error occurred.
• Payload returns the a new Payload instance after a successful call to the iterator's Next method.
• Error returns the last error ...