Interface Input

api.go:58–82

Input is an interface representing an object that produces (fetches) datas for the filter.

// Input is an interface representing an object that produces
// (fetches) datas for the filter.
type Input interface {
	// Start fetching data and pushing it into the channel.
	// If this call blocks forever, the topology is permanent and
	// acts like a long-running daemon; if this calls exits after
	// it has finished, the topology is meant to be run as a task
	// to process a fixed-size input, and baker will cleanly shutdown
	// after all inputs have been fully processed.
	Run(output chan<- *Data) error

	// Force the input to stop as clean as possible, at a good boundary.
	// This is usually issued at the user's request of exiting the process.
	// For instance, it might make sense to finish processing the current
	// batch of data or the current file, and then save in stable storage
	// the checkpoint to resume it later.
	Stop()

	// Return stats about the input
	Stats() InputStats

	// This function is called when the filter is finished with
	// the memory received through the input channel. Since the
	// memory was allocated by Input, it is returned to it
	// so that it might be recycled.
	FreeMem(data *Data)
}

// Filter represents a data filter; a filter is a function that processes
// records. A filter can discard, transform, forward and even create records.