DevOps: What is distributed tracing?

1// OpenTelemetry
2import { trace } from "@opentelemetry/api";
3
4const tracer = trace.getTracer("my-app");
5
6async function handleRequest(req) {
7  return tracer.startActiveSpan("handleRequest", async (span) => {
8    try {
9      span.setAttribute("http.method", req.method);
10      span.setAttribute("http.url", req.url);
11
12      const result = await callServiceA(req);
13      span.setAttribute("service.a.result", "success");
14
15      return result;
16    } catch (err) {
17      span.setAttribute("error", true);
18      span.recordException(err);
19      throw err;
20    } finally {
21      span.end();
22    }
23  });
24}