segments

Documentation

Overview

This package is home to all pipeline segment implementations. Generally, every segment lives in its own package, implements the Segment interface, embeds the BaseSegment to take care of the I/O side of things, and has an additional init() function to register itself using RegisterSegment.

Index

• Variables
• func RegisterSegment(name string, s Segment)
• func TestSegment(name string, config map[string]string, msg *flow.FlowMessage) *flow.FlowMessage
• type BaseSegment
  • func (segment *BaseSegment) Rewire(in <-chan *flow.FlowMessage, out chan<- *flow.FlowMessage)
• type Segment
  • func LookupSegment(name string) Segment

Variables

var (
	ContainerVolumePrefix = ""
)

Functions

func RegisterSegment

func RegisterSegment(name string, s Segment)

Used by Segments to register themselves in their init() functions. Errors and exits immediately on conflicts.

func TestSegment

func TestSegment(name string, config map[string]string, msg *flow.FlowMessage) *flow.FlowMessage

Used by the tests to run single flow messages through a segment.

Types

type BaseSegment

type BaseSegment struct {
	In  <-chan *flow.FlowMessage
	Out chan<- *flow.FlowMessage
}

Serves as a basis for any Segment implementations. Segments embedding this type only need the New and the Run methods to be compliant to the Segment interface.

func (*BaseSegment) Rewire

func (segment *BaseSegment) Rewire(in <-chan *flow.FlowMessage, out chan<- *flow.FlowMessage)

This function rewires this Segment with the provided channels. This is typically called only by pipeline.New() and present in any Segment implementation.

type Segment

type Segment interface {
	New(config map[string]string) Segment                      // for reading the provided config
	Run(wg *sync.WaitGroup)                                    // goroutine, must close(segment.Out) when segment.In is closed
	Rewire(<-chan *flow.FlowMessage, chan<- *flow.FlowMessage) // embed this using BaseSegment
}

This interface is central to an Pipeline object, as it operates on a list of them. In general, Segments should embed the BaseSegment to provide the Rewire function and the associated vars.

func LookupSegment

func LookupSegment(name string) Segment

Used by the pipeline package to convert segment names in configuration to actual Segment objects.