file-analyzer

File Analyzer - Two-Service Architecture

A two-service example demonstrating how an API gateway can trigger workflow tasks remotely. An Express API service accepts CSV file uploads and dispatches analysis to a separate workflow service using the Render Client SDK.

What you'll learn

• Two-service architecture (API service + workflow service)
• Using the Render Client SDK (Render class) to trigger tasks remotely
• File upload handling with Express and Multer
• Error handling with ClientError and ServerError

Architecture

User → API Service (Express) → Render API → Workflow Service
         ├── POST /analyze           └── analyzeFile (task)
         └── POST /analyze-task/:name

API Service (api-service/)

An Express web server that:

• Accepts CSV file uploads via POST /analyze
• Calls client.workflows.runTask() to trigger analysis on the workflow service
• Returns results to the caller

Workflow Service (workflow-service/)

A workflow service that:

• Defines the analyzeFile task for CSV analysis
• Parses CSV data, computes column statistics, and detects data quality issues

Prerequisites

• A Render API key
• Both services deployed on Render

Setup

Workflow Service

cd workflow-service
npm install
npm run build
npm start

API Service

cd api-service
cp .env.example .env
# Edit .env: set RENDER_API_KEY and WORKFLOW_SERVICE_SLUG
npm install
npm run build
npm start

Sample files

The sample_files/ directory contains example CSV files for testing:

• sales_data.csv — sales transaction data
• customer_data.csv — customer information data

Deploy to Render

Deploy both services:

1. Workflow Service — Create a Workflow service

   • Build command: cd workflow-service && npm install && npm run build
   • Start command: cd workflow-service && npm start

2. API Service — Create a Web Service

   • Build command: cd api-service && npm install && npm run build
   • Start command: cd api-service && npm start
   • Environment variables:
     • RENDER_API_KEY — your Render API key
     • WORKFLOW_SERVICE_SLUG — the slug of the workflow service