Add graceful shutdown to Blink (#11523)

bskylink/src/shutdown.test.ts

@@ -0,0 +1,63 @@
+import assert from 'node:assert'
+import events from 'node:events'
+import http from 'node:http'
+import {describe, it} from 'node:test'
+
+import {createHttpTerminator} from 'http-terminator'
+
+import {REQUEST_DRAIN_TIMEOUT_MS} from './shutdown.js'
+
+describe('HTTP shutdown', () => {
+  it('allows in-flight requests to finish during the drain window', async () => {
+    let beginRequest = () => {}
+    const requestStarted = new Promise<void>(resolve => {
+      beginRequest = () => resolve(undefined)
+    })
+    let finishRequest = () => {}
+    const releaseRequest = new Promise<void>(resolve => {
+      finishRequest = () => resolve(undefined)
+    })
+
+    const server = http.createServer(async (_req, res) => {
+      beginRequest()
+      await releaseRequest
+      res.end('finished')
+    })
+    server.listen(0, '127.0.0.1')
+    await events.once(server, 'listening')
+
+    const address = server.address()
+    assert.ok(address && typeof address !== 'string')
+
+    const responsePromise = fetch(`http://127.0.0.1:${address.port}`)
+    await requestStarted
+
+    const terminator = createHttpTerminator({
+      server,
+      gracefulTerminationTimeout: REQUEST_DRAIN_TIMEOUT_MS,
+    })
+    let termination: Promise<void> | undefined
+    try {
+      let terminated = false
+      termination = terminator.terminate().then(() => {
+        terminated = true
+      })
+
+      await new Promise(resolve => setTimeout(resolve, 25))
+      assert.strictEqual(terminated, false)
+
+      finishRequest()
+      const response = await responsePromise
+      assert.strictEqual(await response.text(), 'finished')
+      await termination
+      assert.strictEqual(terminated, true)
+    } finally {
+      finishRequest()
+      await (termination ?? terminator.terminate())
+    }
+  })
+
+  it('uses the shared 60 second request drain budget', () => {
+    assert.strictEqual(REQUEST_DRAIN_TIMEOUT_MS, 60_000)
+  })
+})