koa-timeout 1.6.6
Install from the command line:
Learn more about npm packages
$ npm install @uswitch/koa-timeout@1.6.6
Install via package.json:
"@uswitch/koa-timeout": "1.6.6"
About this version
A Koa middleware to handle timeouts correctly
koa-timeout
uses
Promise.race
to race a setTimeout
against your Koa middlewares/response.
Middlewares
A 1s B 2s C 3s D 4s
╭─────┴────────┴─────╳╌╌╌╌┴╌╌╌╌╌╌╌╌╌┴╌╌╌╌╌
Req ─────┤
╰────────────────────┬──→ 408 - 2500ms
Timeout
2.5s
In this example, a request has come in and the timeout is racing
middlewares, A
, B
, C
& D
. However, the timeout is triggered
causing a 408
response after 2500ms
.
The ╳
signifys a short circuit and prevents middlewares C
&
D
from running.
Middlewares
A 1s B 2s C 3s D 4s
╭─────┴────────┴─────────┴─────────┴──────╮
│ │
Req ─────┤ ╰──→ 200 - 4500ms
│
╰─────────────────────────────────────────╳╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╮
Timeout
5s
In this example, all 4 middlewares - A
, B
, C
& D
- have
finished, resulting in a 200
response after ~4500ms
. The timeout
is then cleared, signified by the ╳
.
The middleware can be configured with a custom timeout time and status code.
import Koa from 'koa'
import timeout from '@uswitch/koa-timeout'
const app = new Koa()
app.use(timeout(1000)) // 1s timeout
app.use(timeout(1000, { status: 499 })) // 1s timeout with 499 status
N.B. By default, koa-timeout
does not short circuit the
other middlewares. This means that the in-flight request will continue to be
processed even though a response has already been sent.
This behaviour can be useful in development to see where the slow parts of the request are, however, in production you probably want to kill the request as soon as possible.
This will prevent the next middleware after a timeout from triggering.
import { shortCircuit } from '@uswitch/koa-timeout'
app.use(timeout(5000))
app.get('*', shortCircuit(handleInitialState))
app.get('*', shortCircuit(handleRendering))
app.get('*', shortCircuit(handleReturn))
// Or
app.get('*', ...shortCircuit(handleInitialState, handleRendering, handleReturn))
N.B. when calling with multiple middlewares, make sure
to spread the result!
i.e. ...shortCircuit(a, b, c)