SIGINT spawn testing

index.js

const http = require("http");
const spawn = require("child_process").spawn;
const IS_CHILD = process.argv[2] === "--child";
const DETACHED = process.argv[2] === "--detached";
const port = IS_CHILD ? 3001 : 3000;

const requestHandler = (request, response) => {
  console.log(request.url);
  response.end("Hello Node.js Server!");
};

let child = null;
if (!IS_CHILD) {
  child = spawn("node", ["index.js", "--child"], {
    stdio: "inherit",
    detached: DETACHED
  });
}

const log = (message, ...args) => {
  console.log((IS_CHILD ? "Child: " : "Parent: ") + message, ...args);
};

const server = http.createServer(requestHandler);

server.listen(port, err => {
  if (err) {
    return log("something bad happened", err);
  }
  log(`server is listening on ${port}`);
});

const close = () => {
  log("Closing");
  if (child) {
    log("Killing child");
    child.kill("SIGTERM");
  }
  server.close(() => {
    log("Http server closed.");
  });

  process.exit();
};

["SIGTERM", "SIGHUP", "SIGQUIT"].forEach(function(signal) {
  process.on(signal, function() {
    log("received signal", signal);
    log("Closing http server.");
    close();
  });
});

let sigints = 0;
process.on("SIGINT", () => {
  if (IS_CHILD && !DETACHED) {
    log("received SIGINT, ignoring...");
    return;
  }
  sigints = sigints + 1;
  if (sigints < 2) {
    log("received first SIGINT, ignoring...");
  } else {
    log("received another SIGINT, closing");
    close();
  }
});

$ node index.js
Parent: server is listening on 3000
Child: server is listening on 3001
^CParent: received first SIGINT, ignoring...
Child: received SIGINT, ignoring...
^CChild: received SIGINT, ignoring...
Parent: received another SIGINT, closing
Parent: Closing
Parent: Killing child
Child: received signal SIGTERM
Child: Closing http server.
Child: Closing

$ node index.js --detached
Parent: server is listening on 3000
Child: server is listening on 3001
^CParent: received first SIGINT, ignoring...
^CParent: received another SIGINT, closing
Parent: Closing
Parent: Killing child
Child: received signal SIGTERM
Child: Closing http server.
Child: Closing