Deno 中的分布式追踪与上下文传播

import { trace } from "npm:@opentelemetry/api@1";

const tracer = trace.getTracer("api-server", "1.0.0");

// Create a simple API server with Deno.serve
Deno.serve({ port: 8000 }, (req) => {
  return tracer.startActiveSpan("process-api-request", async (span) => {
    // Add attributes to the span for better context
    span.setAttribute("http.route", "/");
    span.updateName("GET /");

    // Add a span event to see in traces
    span.addEvent("processing_request", {
      request_id: crypto.randomUUID(),
      timestamp: Date.now(),
    });

    // Simulate processing time
    await new Promise((resolve) => setTimeout(resolve, 50));

    console.log("Server: Processing request in trace context");

    // End the span when we're done
    span.end();

    return new Response(JSON.stringify({ message: "Hello from server!" }), {
      headers: { "Content-Type": "application/json" },
    });
  });
});

import { SpanStatusCode, trace } from "npm:@opentelemetry/api@1";

const tracer = trace.getTracer("api-client", "1.0.0");

// Create a parent span for the client operation
await tracer.startActiveSpan("call-api", async (parentSpan) => {
  try {
    console.log("Client: Starting API call");

    // The fetch call inside this span will automatically:
    // 1. Create a child span for the fetch operation
    // 2. Inject the trace context into the outgoing request headers
    const response = await fetch("http://localhost:8000/");
    const data = await response.json();

    console.log(`Client: Received response: ${JSON.stringify(data)}`);

    parentSpan.addEvent("received_response", {
      status: response.status,
      timestamp: Date.now(),
    });
  } catch (error) {
    console.error("Error calling API:", error);
    if (error instanceof Error) {
      parentSpan.recordException(error);
    }
    parentSpan.setStatus({
      code: SpanStatusCode.ERROR,
      message: error instanceof Error ? error.message : String(error),
    });
  } finally {
    parentSpan.end();
  }
});