sequential

Sequential Workflow Example

This example demonstrates the most basic usage of gorkflow: a linear sequence of steps where the output of one step becomes the input of the next.

Overview

The workflow performs a simple mathematical operation: (Val1 + Val2) * Mult, and then formats the result into a string.

It showcases:

• Type-safe data passing: How data flows between steps using Go generics.
• Step Configuration: Setting retries, timeouts, and backoff strategies per step.
• Sequential Execution: Using .Sequence() to chain steps.

Workflow Structure

The workflow consists of three steps executed in order:

1. Add Step (add):

   • Input: WorkflowInput (Val1, Val2, Mult)
   • Action: Adds Val1 and Val2.
   • Output: AddOutput (Sum, Mult) - Passes Mult through for the next step.

2. Multiply Step (multiply):

   • Input: AddOutput (Value, Mult)
   • Action: Multiplies the sum from the previous step by Mult.
   • Output: MultiplyOutput (Value)
   • Configuration: This step overrides default settings with 5 retries and exponential backoff.

3. Format Step (format):

   • Input: MultiplyOutput (Value)
   • Action: Formats the final number into a message string.
   • Output: FormatOutput (Message)

Data Flow

graph LR
    Input[WorkflowInput] --> Add[Add Step]
    Add -->|AddOutput| Multiply[Multiply Step]
    Multiply -->|MultiplyOutput| Format[Format Step]
    Format --> Output[FormatOutput]

Loading

Running the Example

1. Start the Server:

   go run main/main.go

   The server will start on http://localhost:3000.

2. Trigger the Workflow: Send a POST request to start the workflow:

   curl -X POST http://localhost:3000/api/v1/workflows/simple-math \
     -H "Content-Type: application/json" \
     -d '{"val1": 10, "val2": 5, "mult": 2}'

3. Check Status: Use the runId returned from the previous request:

   curl http://localhost:3000/api/v1/workflows/<runId>

Key Code Concepts

Defining Steps

Steps are defined using gorkflow.NewStep. Notice how the input and output types are strongly typed:

func NewAddStep() *gorkflow.Step[WorkflowInput, AddOutput] {
    return gorkflow.NewStep(
        "add",
        "Add Numbers",
        func(ctx *gorkflow.StepContext, input WorkflowInput) (AddOutput, error) {
            // ... implementation
        },
    )
}

Building the Workflow

The workflow is assembled using the builder pattern:

builder.NewWorkflow("sequential", "Simple Math Workflow").
    Sequence(
        NewAddStep(),
        NewMultiplyStep(),
        NewFormatStep(),
    ).
    Build()