Graceful shutdown

Problem

I’d like to shutdown my application gracefully and do some database work before I exit the process myself.

However, Prisma exits the process on a SIGINT event on its own. Even though I got a work-around by monkey-patching “process.exit”, the Prisma query engine still exits with the SIGINT event and I’m unable to execute queries therefore.

The Node.js process already received a SIGINT signal, therefore the Prisma query engine exited and your request can't be processed.

Suggested solution

1. Make prisma stop listening to process events by setting an option
2. Stop the engines manually by executing a stop method (?) just after the application is ready to exit

Alternatives

here’s the very hacky work-around that I use (though I’d appreciate something else)

const realProcessExit = process.exit;
process.exit = () => {
  // Monkey-patch process.exit because Prisma wants to exit before
  // we can shut down gracefully
};

import { PrismaClient } from "@prisma/client";

["EXIT", "SIGINT", "SIGUSR1", "SIGUSR2", "uncaughtException", "SIGTERM"].forEach((eventType) => {
  const previousListeners = process.listeners(eventType);
  process.removeAllListeners(eventType);

  process.once(eventType, async (param) => {
    await shutdown();

    // Make prisma stop the engines after the application is ready to exit
    previousListeners.forEach((l) => l(param));

    if (eventType !== "EXIT") {
      realProcessExit();
    }
  });
});

[microwavekonijn]

All I want is to call $disconnect myself even in the case of a SIGINT, that way I have completely predictable behavior for my app(so the app will react to the SIGINT/process closing).

I looked at the code and found that I can just returned a never resolving promise in the callback for beforeExit, blocking the SIGINT behavior.

[dfee]

The opt-out and callback on exit seems to make sense though. I just discovered that the reason my NestJs app isn’t performing it’s onApplicationShutdown cleanups are that Prisma is killing the process before it gets there.

I know this is slatted for current development, so wanted to get my thoughts in. Thanks!