koa-server-timing

Koa 2 Server-Timing header middleware.

Installation

$ npm install koa-server-timing

API

const Koa = require('koa');
const app = new Koa();
app.use(require('koa-server-timing')({
  total: true, /* default to NODE_ENV !== 'production' */
  convertMetricUnit: time => time * 1000, /* default to time => time */
}));

ctx.state.timings.startSpan('A Task description', 'taskSlug' /* optional, will be created a-task-description, if missed */)

/* ... do some long task to measure here */
ctx.state.timings.stopSpan('A Task description' /* or 'taskSlug' or return from startSpan */);

Options

• total where do you want to see total processing time in Server-Timings
• convertMetricUnit in what format do you want the serverTimings metrics? (default is seconds)

Example

const timings = require('koa-server-timing');
const koa = require('koa');
const db = require('./mongoose');
const app = koa();

app.use(timings());

app.listen(3000);

console.log('listening on port 3000');

app.use(async (ctx, next) => {
    ctx.state.timings.startSpan('Query DB for User object');
    const user = await db.User.findOne({ email: 'test@test.com' }).exec();
    ctx.state.timings.stopSpan('Query DB for User object'); // or just pass return of startSpan (it will be a slug)
})

Why

• Small, no dependencies, 100% test coverage
• Uses process.hrtime, so, no extra timers and very precise

See also

• See @thomasbrueggemann/node-servertiming for non-Koa version that uses Timers

License

MIT