Workflow

An easy-to-use workflow automation library for Go. Supports conditional branching, parallel execution, embedded scripting, and execution checkpointing.

Think of it like a lightweight hybrid of Temporal and AWS Step Functions.

When defining steps, you have access to string templating and scripting features using the Risor language.

Main Concepts

| Concept | Description | |---------|-------------| | Workflow | A repeatable process defined as a directed graph of steps | | Steps | Individual nodes in the workflow graph | | Activities | Functions that perform the actual work | | Edges | Define flow between steps | | Execution | A single run of a workflow | | State | Shared mutable state that persists for the duration of an execution |

How They Work Together

Workflows define Steps that execute Activities. An Execution is a single run of a workflow. When a step finishes, its outgoing Edges are evaluated and the next step(s) are selected based on any associated conditions. The State may be read and written to by the activities.

Quick Example

package main

import (
	"context"
	"fmt"
	"log"

	"github.com/deepnoodle-ai/workflow"
	"github.com/deepnoodle-ai/workflow/activities"
)

func main() {

	attempt := 0

	myOperation := func(ctx workflow.Context, input map[string]any) (string, error) {
		attempt++
		if attempt < 3 { // Simulated failure
			return "", fmt.Errorf("service is temporarily unavailable")
		}
		return "SUCCESS", nil
	}

	w, err := workflow.New(workflow.Options{
		Name: "demo",
		Steps: []*workflow.Step{
			{
				Name:     "Call My Operation",
				Activity: "my_operation",
				Store:    "result",
				Retry:    []*workflow.RetryConfig{{MaxRetries: 2}},
				Next:     []*workflow.Edge{{Step: "Finish"}},
			},
			{
				Name:     "Finish",
				Activity: "print",
				Parameters: map[string]any{
					"message": "🎉 Workflow completed successfully! Result: ${state.result}",
				},
			},
		},
	})
	if err != nil {
		log.Fatal(err)
	}

	execution, err := workflow.NewExecution(workflow.ExecutionOptions{
		Workflow: w,
		Logger:   workflow.NewLogger(),
		Activities: []workflow.Activity{
			workflow.NewTypedActivityFunction("my_operation", myOperation),
			activities.NewPrintActivity(),
		},
	})
	if err != nil {
		log.Fatal(err)
	}

	if err := execution.Run(context.Background()); err != nil {
		log.Fatal(err)
	}
}