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Overview

faas-flow allows you to realize OpenFaaS function composition with ease. By defining a simple pipeline, you can orchestrate multiple functions without having to worry about internals.

import faasflow "github.com/s8sg/faas-flow"

func Define(flow *faasflow.Workflow, context *faasflow.Context) (err error) {
  flow.Apply("Func1").Apply("Func2")
}

After building and deploying, it will give you a function that orchestrates calling Func2 with the output of Func1

Pipeline Definition

By supplying a number of pipeline operators, complex composition can be achieved with little work:

The above pipeline can be achieved with little, but powerfull code:

SYNC-Chain

func Define(flow *faasflow.Workflow, context *faasflow.Context) (err error) {
     flow.Apply("func1").Apply("func2").
	  Modify(func(data []byte) ([]byte, error) {
	  	// Do something
		return data, nil
	  })
     return nil
}

AYNC-Chain

func Define(flow *faasflow.Workflow, context *faasflow.Context) (err error) {

     dag := flow.Dag()
     dag.AddFunction("n1", "func1")
     dag.AddFunction("n2", "func2").
        Modify(func(data []byte) ([]byte, error) {
	        // Do something
               	return data
        }).
     dag.Callback("n3","storage.io/bucket?id=3345612358265349126&file=result.dat")
     dag.AddEdge("n1", "n2")
     dag.AddEdge("n2", "n3")
     flow.OnFailure(func(err error) {
              // failure handler
        }).
        Finally(func(state string) {
              // cleanup code
        })
     
     return nil
}

DAG-Call and Parallel

func Define(flow *faasflow.Workflow, context *faasflow.Context) (err error) {

     dag := flow.Dag()
     dag.AddModifier("n1", func(data []byte) ([]byte, error) {
     		// do something
		return data, nil
     })
     dag.AddFunction("n2", "func1")
     dag.AddFunction("n3", "func2").Modify("n4", func(data []byte) ([]byte, error) {
     		// do something
		return data, nil
     })
     dag.AddCallback("n4", "storage.io/bucket?id=3345612358265349126&file=result")
     dag.AddEdge("n1", "n2")
     dag.AddEdge("n1", "n3")
     dag.AddEdge("n2", "n4")
     dag.AddEdge("n3", "n4")

     return nil
}

Dynamic Branching
Check example dag: https://github.com/s8sg/branching-in-faas-flow