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Petal Flow Getting Started

Getting Started

Section titled “Getting Started”

This guide walks you through building your first Petal Flow workflow graph.

Prerequisites

Section titled “Prerequisites”
  • Go 1.21 or later
  • A Go module initialized (go mod init)

Installation

Section titled “Installation”
Terminal window
go get github.com/petal-labs/petalflow

Your First Workflow

Section titled “Your First Workflow”
  1. Create a graph — Graphs are containers for nodes and edges.
  2. Add nodes — Nodes perform work on the envelope data.
  3. Set the entry point — Define where execution begins.
  4. Run with the runtime — Execute the graph and get results.
package main


import (
    "context"
    "fmt"
    "strings"


    "github.com/petal-labs/petalflow"
)


func main() {
    // Create a new graph with a name
    g := petalflow.NewGraph("hello")


    // Create a function node that transforms input
    node := petalflow.NewFuncNode("greet", func(ctx context.Context, env *petalflow.Envelope) (*petalflow.Envelope, error) {
        name := env.GetVarString("name")
        env.SetVar("greeting", fmt.Sprintf("Hello, %s!", strings.ToUpper(name)))
        return env, nil
    })


    // Add the node and set it as the entry point
    g.AddNode(node)
    g.SetEntry("greet")


    // Create an envelope with initial data
    env := petalflow.NewEnvelope().WithVar("name", "world")


    // Run the graph
    runtime := petalflow.NewRuntime()
    result, err := runtime.Run(context.Background(), g, env, petalflow.DefaultRunOptions())
    if err != nil {
        fmt.Printf("Error: %v\n", err)
        return
    }


    fmt.Println(result.GetVarString("greeting"))
    // Output: Hello, WORLD!
}

Next Steps

Section titled “Next Steps”