Distributed Tracing（分散式追蹤）

// OpenTelemetry Tracing 設定
using OpenTelemetry.Trace;
using System.Diagnostics;
 
var builder = WebApplication.CreateBuilder(args);
 
builder.Services.AddOpenTelemetry()
    .WithTracing(tracing => tracing
        .SetResourceBuilder(ResourceBuilder.CreateDefault()
            .AddService("order-service"))
        .AddAspNetCoreInstrumentation()  // 自動追蹤 HTTP 請求
        .AddHttpClientInstrumentation()   // 自動追蹤 HTTP Client
        .AddSqlClientInstrumentation()    // 自動追蹤 SQL 查詢
        .AddOtlpExporter(opts =>
            opts.Endpoint = new Uri("http://otel-collector:4317")));
 
// 自訂 Span
private static readonly ActivitySource Source = new("OrderService");
 
app.MapPost("/api/orders", async (OrderRequest req) =>
{
    using var activity = Source.StartActivity("ProcessOrder");
    activity?.SetTag("order.customer_id", req.CustomerId);
    activity?.SetTag("order.item_count", req.Items.Count);
 
    // 子 Span：驗證庫存
    using (var checkStock = Source.StartActivity("CheckInventory"))
    {
        var stock = await inventoryClient.GetStockAsync(req.Items);
        checkStock?.SetTag("inventory.available", stock.IsAvailable);
    }
 
    // 子 Span：建立訂單
    using (var createOrder = Source.StartActivity("CreateOrder"))
    {
        var order = await db.Orders.AddAsync(new Order(req));
        await db.SaveChangesAsync();
        createOrder?.SetTag("order.id", order.Entity.Id);
    }
 
    activity?.SetStatus(ActivityStatusCode.Ok);
    return Results.Ok();
});

import { trace, SpanStatusCode } from "@opentelemetry/api";
import { NodeSDK } from "@opentelemetry/sdk-node";
import { OTLPTraceExporter } from "@opentelemetry/exporter-trace-otlp-grpc";
 
// 初始化
const sdk = new NodeSDK({
  serviceName: "order-service",
  traceExporter: new OTLPTraceExporter({
    url: "http://otel-collector:4317",
  }),
});
sdk.start();
 
const tracer = trace.getTracer("order-service");
 
// 手動建立 Span
app.post("/api/orders", async (req, res) => {
  const span = tracer.startSpan("ProcessOrder", {
    attributes: {
      "order.customer_id": req.body.customerId,
      "order.item_count": req.body.items.length,
    },
  });
 
  try {
    // 子 Span：呼叫支付服務
    const paymentSpan = tracer.startSpan("CallPaymentService");
    const payment = await paymentService.charge(req.body);
    paymentSpan.setAttribute("payment.id", payment.id);
    paymentSpan.end();
 
    span.setStatus({ code: SpanStatusCode.OK });
    res.json({ orderId: payment.orderId });
  } catch (error) {
    span.setStatus({ code: SpanStatusCode.ERROR, message: error.message });
    span.recordException(error);
    res.status(500).json({ error: "Order failed" });
  } finally {
    span.end();
  }
});

from opentelemetry import trace
from opentelemetry.sdk.trace import TracerProvider
from opentelemetry.sdk.trace.export import BatchSpanProcessor
from opentelemetry.exporter.otlp.proto.grpc.trace_exporter import OTLPSpanExporter
from opentelemetry.instrumentation.fastapi import FastAPIInstrumentor
from opentelemetry.instrumentation.httpx import HTTPXClientInstrumentor
 
# 初始化
provider = TracerProvider()
provider.add_span_processor(
    BatchSpanProcessor(OTLPSpanExporter(endpoint="http://otel-collector:4317"))
)
trace.set_tracer_provider(provider)
tracer = trace.get_tracer("order-service")
 
# 自動 Instrumentation
FastAPIInstrumentor.instrument_app(app)
HTTPXClientInstrumentor().instrument()
 
@app.post("/api/orders")
async def place_order(request: OrderRequest):
    with tracer.start_as_current_span("process_order") as span:
        span.set_attribute("order.customer_id", request.customer_id)
 
        # 子 Span
        with tracer.start_as_current_span("check_inventory") as inv_span:
            stock = await inventory_client.get_stock(request.items)
            inv_span.set_attribute("inventory.available", stock.available)
 
        with tracer.start_as_current_span("save_to_db") as db_span:
            order = await save_order(request)
            db_span.set_attribute("order.id", order.id)
 
        span.set_status(trace.StatusCode.OK)
        return {"order_id": order.id}