workflow.fan_out

Operation: workflow.fan_out
Category: workflow
Tags: fan-out, parallel, dynamic

Explode an array into N parallel dynamic branches

Runtime

Type: Native (built-in)
Timeout: 300s
Retries: 3 (ExponentialWithJitter)

Inputs

Name	Type	Required	Default	Description
items	JSON	Yes	—	Array of items to fan out

Outputs

Name	Type	Description
items	JSON	Array passed through for branch spawning
count	Number	Number of items

Usage

TypeScript

import { WorkflowBuilder } from "@fabric-platform/sdk";

const workflow = new WorkflowBuilder("my-workflow")
  .node("workflow-fan-out", "transform", (n) =>
    n.config({
      operation: "workflow.fan_out",
      // ... node-specific config
    })
  )
  .build();

Python

from fabric_platform import FabricClient

fabric = FabricClient(api_key="fab_xxx")

wf_id = fabric.upsert_workflow("my-workflow", nodes=[
    {
        "key": "workflow-fan-out",
        "kind": "transform",
    },
])

Rust

use fabric_sdk::FabricClient;

let client = FabricClient::new("http://localhost:3001", api_key)?;

let wf_id = client.upsert_workflow("my-workflow", serde_json::json!({
    "nodes": [{
        "key": "workflow-fan-out",
        "kind": "transform"
    }]
})).await?;

curl

curl -X POST http://localhost:3001/v1/workflow-definitions \
  -H "Authorization: Bearer $FABRIC_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "name": "my-workflow",
    "nodes": [{
      "key": "workflow-fan-out",
      "kind": "transform"
    }]
  }'

Example

{
  "key": "fan-out-segments",
  "operation": "workflow.fan_out",
  "config": { "branch_kind": "process-segment" },
  "inputs": [{ "name": "items", "path": "$context.segments" }],
  "outputs": [{ "name": "count", "path": "$context.segment_count" }]
}

Common Errors

Missing required input: items

Cause: The items input is null or not bound — fan_out needs an array to split

Fix: Bind items to a context path containing a JSON array from an upstream node