DEno 2.2 :: OpenTelemetry

1.txt

$deno --version
deno 2.2.1 (stable, release, aarch64-apple-darwin)
v8 13.4.114.9-rusty
typescript 5.7.3

compose.yml

services:
  lgtm:
    image: grafana/otel-lgtm
    ports:
      - 3000:3000
      - 4317:4317
      - 4318:4318
  
  service1:
    build: ./service1
    ports:
      - 8000:8000
    environment:
      - OTEL_DENO=true
      - OTEL_SERVICE_NAME=service1
      - OTEL_EXPORTER_OTLP_INSECURE=true
      - OTEL_EXPORTER_OTLP_ENDPOINT=http://lgtm:4318
      - OTEL_PROPAGATORS=b3

Dockerfile

FROM denoland/deno:2.2.1
WORKDIR /app
COPY . .
RUN deno cache main.ts
EXPOSE 8000
CMD ["deno", "run", "--allow-net", "--unstable-otel", "server.ts"]

server.ts

import { trace } from "npm:@opentelemetry/[email protected]";
const tracer = trace.getTracer("example-tracer");

Deno.serve(async (req) => {
  console.log("Received request for", req.url);

  // Call internal function
  await doWork();

  // Call external api with fetch
  const response = await fetch("http://service2:8000");
  const body = new Uint8Array(await response.arrayBuffer());

  if (!response.ok) {
    return new Response("Error fetching data", { status: response.status });
  }
  const text = new TextDecoder().decode(body);
  return new Response("Hello world deno" + text);
});

// Internal function with custom trace span
async function doWork() {
  return tracer.startActiveSpan("doWork", async (span) => {
    span.setAttribute("key", "value");
    await new Promise((resolve) => setTimeout(resolve, 1000));
    span.end();
  });
}