OpenTelemetry Instrumentation with Kopai

Guide for instrumenting applications with OpenTelemetry SDK and validating telemetry locally using Kopai.

Quick Reference

# Start backend
npx @kopai/app start

# Configure app
export OTEL_EXPORTER_OTLP_ENDPOINT=http://localhost:4318
export OTEL_SERVICE_NAME=my-service

# Validate telemetry
npx @kopai/cli traces search --service my-service --json
npx @kopai/cli logs search --service my-service --json
npx @kopai/cli metrics discover --json

Workflow

1. Start backend — npx @kopai/app start
2. Set env vars — OTEL_EXPORTER_OTLP_ENDPOINT=http://localhost:4318 and OTEL_SERVICE_NAME=<name>
3. Instrument app — install SDK + auto-instrumentation for your language (see rules below)
4. Validate — npx @kopai/cli traces search --service <name> --json. If empty: check endpoint/port, verify app is running and generating traffic, wait 10-30s and retry
5. Troubleshoot — if still no data, check rules in section 4 below

Quick Example (Node.js)

npm install @opentelemetry/sdk-node @opentelemetry/auto-instrumentations-node @opentelemetry/api

Create instrumentation.mjs:

import { NodeSDK } from "@opentelemetry/sdk-node";
import { getNodeAutoInstrumentations } from "@opentelemetry/auto-instrumentations-node";
const sdk = new NodeSDK({ instrumentations: [getNodeAutoInstrumentations()] });
sdk.start();

Run: node --import ./instrumentation.mjs server.mjs

Rules

1. Setup (CRITICAL)

• setup-backend - Start Kopai Backend
• setup-environment - Configure Environment

2. Language SDKs (HIGH)

• lang-nodejs - Node.js Instrumentation
• lang-nextjs - Next.js Instrumentation
• lang-python - Python Instrumentation
• lang-go - Go Instrumentation
• lang-java - Java Instrumentation
• lang-dotnet - .NET Instrumentation
• lang-ruby - Ruby Instrumentation
• lang-php - PHP Instrumentation
• lang-rust - Rust Instrumentation
• lang-erlang - Erlang/Elixir Instrumentation
• lang-cpp - C++ Instrumentation

3. Validation (HIGH)

• validate-traces - Validate Traces
• validate-logs - Validate Logs
• validate-metrics - Validate Metrics

4. Troubleshooting (MEDIUM)

• troubleshoot-no-data - No Data Received
• troubleshoot-missing-spans - Missing Spans
• troubleshoot-missing-attrs - Missing Attributes
• troubleshoot-wrong-port - Wrong Port

Read rules/<rule-name>.md for details.

References

• cli-reference - Kopai CLI command reference
• otel-docs - OpenTelemetry documentation links
• nextjs-examples - Next.js instrumentation examples