Graceful Shutdown

process.on('SIGINT'/'SIGTERM', handler). Lets a long-running server run cleanup code and call process.exit itself instead of dying instantly, finally closing out http.listen's one remaining gap (graceful shutdown — see).

Like examples/http/http_server.ts, http.listen never returns on its own, so this example needs a way to end deterministically under `make examples` without a real external signal. Rather than the setTimeout+ process.exit trick that example uses, this one sends itself a real SIGINT via process.kill(process.pid, 2) — proving the full round trip (registration -> OS signal delivery -> handler invocation -> graceful exit), not just that process.exit works. Try it interactively too: run this and press Ctrl-C instead of waiting for the scheduled self-signal.

import http from 'http'

let requestCount = 0

process.on('SIGINT', () => {
  console.log('graceful shutdown after ' + requestCount + ' request(s)')
  process.exit(0)
})

// Simulates an external Ctrl-C / `kill -INT`/orchestrator SIGTERM arriving
// shortly after startup, so this example terminates deterministically.
setTimeout(() => {
  process.kill(process.pid, 2) // 2 = SIGINT
}, 300)

console.log('listening on :8090')

http.listen(8090, (req: HttpRequest): { status: number; body: string } => {
  requestCount = requestCount + 1
  return { status: 200, body: 'hello' }
})

View source on GitHubexamples/process/graceful_shutdown.ts

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