Step Machine

Easiest way to handle errors that happen in the middle of a proccess

Background

When you have a collections of steps that need to run and you need to handle errors when something bad happen you can use this package to run and resume those workloads.

Gettings started

Let see a brief example:

package main

import (
	"fmt"

	"github.com/jaswdr/stepmachine"
)

func sum(last stepmachine.Step, current stepmachine.Step) error {
	result := 2 + 2
	current.Set("result", result)
	return nil
}

func addFive(last stepmachine.Step, current stepmachine.Step) error {
	result := last.Get("result").(int)
	result += 5
	current.Set("result", result)
	return nil
}

func main() {
	// declare all steps
	sumStep := stepmachine.NewStep("sum", sum)
	addFiveStep := stepmachine.NewStep("addFive", addFive)

	// create a new step machine with the sumStep as initial step
	m := stepmachine.NewMachine("my step machine name", sumStep, addFiveStep)

	// run the step machine
	lastStep, err := m.Run("", nil)
	if err != nil {
		panic(err)
	}

	fmt.Println(lastStep.Get("result").(int)) // 9

	// if something bad happen you only need to resume the machine
    	savedValues := map[string]interface{}{
        	"result": 5,
    	}
    	m.Resume("addFiveStep", savedValues)
	_, err = m.Run()
	if err != nil {
		panic(err)
	}

	fmt.Println(m.Get("result").(int)) // 9
}

Logging

Is possible to log inside a step and print in the end, use Step.Println() to log a message and Machine.Stack() to retrieve the log stack with all messages.

Author

Jonathan A. Schweder <jonathanschweder@gmail.com>