otel-demo-lite

A minimal multi-language microservices demo for testing OpenTelemetry instrumentation. Simulates an e-commerce backend with services written in Go, Node.js, and Python—all wired up to emit traces, metrics, and logs via OTLP.

What's in here

go/           → checkout, cart, product catalog, shipping, currency, accounting, fraud detection
javascript/   → frontend gateway, payment, ads, email, browser simulator
python/       → recommendations, shipping quotes

The services talk to each other over HTTP. A browser simulator generates fake traffic so you don't have to click around manually.

Running it

With Docker (recommended)

docker-compose up

This spins up:

• All the microservices in one container
• An OpenTelemetry Collector
• Redis for cart storage

Without Docker

Make sure you have Go 1.21+, Node.js 18+, and Python 3.11+ installed.

./run.sh

You'll need an OTel Collector running on localhost:4317 to receive telemetry.

Services

Service	Port	What it does
Frontend	8080	API gateway, routes requests
Payment	8081	Processes charges (5% failure rate for realism)
Shipping	8082	Gets quotes, ships orders
Checkout	8083	Orchestrates the purchase flow
Cart	8084	Redis-backed shopping cart
Product Catalog	8085	Lists products, search
Recommendation	8086	Suggests products
Ad	8087	Serves ads
Email	8088	Order confirmations
Currency	8089	Converts between currencies
Browser Simulator	8090	Generates load, records Web Vitals
Accounting	8091	Consumes orders from Kafka
Fraud Detection	8092	Scans orders (2% detection rate)
Quote	8094	Calculates shipping costs

Telemetry

All services export to the OTel Collector via OTLP (gRPC on 4317, HTTP on 4318). The collector config batches everything and forwards to wherever you point it—by default it's set up for SigNoz but you can swap in Jaeger, Tempo, or anything else.

Each service instruments:

• Traces: HTTP spans, database calls, cross-service propagation
• Metrics: Request counts, latencies, business metrics (order totals, quote amounts)
• Logs: Structured logs with trace context

Load testing

The browser simulator runs automatically and generates traffic. To crank it up:

COUNT=100 docker-compose up

Or hit the frontend directly:

node load-test.js

Configuration

Copy .env.example to .env and configure:

cp .env.example .env

Or pass environment variables directly:

OTLP_ENDPOINT=your-host:4317 OTLP_INSECURE=true docker-compose up

Environment Variables

Variable	Default	Description
OTLP_ENDPOINT	ingest.us.signoz.cloud:443	OTLP endpoint. For self-hosted use your-host:4317
SIGNOZ_INGESTION_KEY	(empty)	SigNoz ingestion key (not needed for self-hosted)
OTLP_INSECURE	false	Set true for self-hosted without TLS
OTLP_INSECURE_SKIP_VERIFY	false	Set true to skip TLS cert verification
COUNT	5	Number of simulated orders per cycle

Load Test Mode

Set COUNT=0 to run services without generating traffic—useful for external load testing:

COUNT=0 docker-compose up

Services will run indefinitely and expose endpoints at http://localhost:8080/api/*.

The collector uses otlp exporter for gRPC (port 4317). Edit otel-collector-config.yaml to point to your backend.