tRPC End-to-End Type Safe APIs · 课时

日志记录与性能计时中间件

使用记录每次调用并测量执行时间的中间件，为您的 tRPC API 构建可观测性。

日志记录与性能计时中间件 是 CoddyKit 上的免费 tRPC End-to-End Type Safe APIs 课时。这是第 4 节课，共 4 节。你可以在下方免费阅读本课时的完整内容 — 然后在浏览器中使用内置代码编辑器和全天候 AI 导师进行实践。这是 tRPC End-to-End Type Safe APIs 学习路径的一部分，你的进度在网页和 CoddyKit 应用中同步。 tRPC End-to-End Type Safe APIs 课程共包含 4 节课。

本课时的部分内容尚未翻译，以英文显示。

Why Observe Every Call?

You already use middleware for auth. Middleware is also perfect for cross-cutting concerns like logging and timing that should apply to many procedures.

Middleware Recap

A tRPC middleware wraps a procedure: it runs code, calls next(), then can run code after the result.

const mw = t.middleware(async (opts) => {
  // before
  const result = await opts.next();
  // after
  return result;
});

A Simple Logger

Log the procedure type and path on every call.

const logger = t.middleware(async ({ path, type, next }) => {
  console.log("-> " + type + " " + path);
  return next();
});

Measuring Duration

Capture the time before and after next() to compute how long the call took.

const timing = t.middleware(async ({ path, next }) => {
  const start = Date.now();
  const result = await next();
  const ms = Date.now() - start;
  console.log(path + " took " + ms + "ms");
  return result;
});

Inspecting the Result

The result tells you whether the call succeeded, useful for logging error rates.

const result = await next();
console.log(result.ok ? "ok" : "error");
return result;

Attaching to a Procedure

Use .use() to apply middleware when defining a base procedure.

const loggedProcedure = t.procedure.use(logger).use(timing);

Reusing Across Routers

Export the enhanced procedure and build all routers from it so logging applies everywhere automatically.

export const appRouter = router({
  ping: loggedProcedure.query(() => "pong"),
});

Adding Request IDs

Generate a unique id per call to correlate logs across services.

const withId = t.middleware(async ({ next, ctx }) => {
  const reqId = crypto.randomUUID();
  return next({ ctx: { ...ctx, reqId } });
});

Structured Logging

Emit JSON instead of plain text so logs are searchable in tools like Datadog or ELK.

console.log(JSON.stringify({ path, type, ms, level: "info" }));

Order of Middleware

Middleware runs in the order added. Put timing outermost so it includes the work of inner middleware.

Sampling Logs

In high-traffic APIs, logging every call is costly. Sample a percentage of requests so you keep visibility without overwhelming your log pipeline.

if (Math.random() < 0.1) console.log(path);

Quick Check

Test your middleware knowledge.

Recap

You added observability with middleware:

Middleware runs code before and after next()
Use it for logging, timing, and request IDs
Build a shared base procedure so it applies everywhere

Good observability makes a tRPC API far easier to debug in production.

常见问题解答

「日志记录与性能计时中间件」课时是免费的吗？

是的 — 「日志记录与性能计时中间件」的完整文本可在网页上免费阅读。要进行交互式练习（内置代码编辑器和全天候 AI 导师）并解锁 tRPC End-to-End Type Safe APIs 课程的其余内容，请升级到 CoddyKit PRO。 tRPC End-to-End Type Safe APIs 课程共包含 4 节课。

「日志记录与性能计时中间件」这节课中我会学到什么？

使用记录每次调用并测量执行时间的中间件，为您的 tRPC API 构建可观测性。你通过在浏览器中直接运行的动手代码来练习 tRPC End-to-End Type Safe APIs，全天候 AI 导师会在你学习这节课的过程中回答你的问题。

学习 tRPC End-to-End Type Safe APIs 需要有经验吗？

无需任何先前经验。CoddyKit 上的 tRPC End-to-End Type Safe APIs 课程适合初学者到高级学习者，你可以从这里开始或从头开始，按照自己的节奏学习。这是第 4 节课，共 4 节。

「日志记录与性能计时中间件」课时需要多长时间？

大多数 CoddyKit 课程大约需要 5–10 分钟。每节课都很精短且互动，所以你能稳步进步，并在网页和应用中从离开的地方继续。

我能在这节 tRPC End-to-End Type Safe APIs 课中编写并运行代码吗？

能。每节 tRPC End-to-End Type Safe APIs 课都包含内置代码编辑器，你可以在浏览器中直接编写并运行真实代码，并获得即时 AI 反馈 — 无需本地设置。

此课程中的所有课时

← 返回 tRPC End-to-End Type Safe APIs