"Cannot use a session that has ended" when the app is killed

Draft Mongo-GKE problem

Got error Cannot use a session that has ended. Seems like the app still getting request when closing the MongoDB connection.

Tried this forum but no luck

I use Nodejs with mongoose 5.8.1 and GKE as a infrastructure. Here’s the error stack

MongoError: Cannot use a session that has ended
    at applySession (/app/node_modules/mongodb/lib/core/sessions.js:698:12)
    at _command (/app/node_modules/mongodb/lib/core/wireprotocol/command.js:87:17)
    at command (/app/node_modules/mongodb/lib/core/wireprotocol/command.js:28:5)
    at Object.query (/app/node_modules/mongodb/lib/core/wireprotocol/query.js:70:3)
    at Connection.query (/app/node_modules/mongodb/lib/cmap/connection.js:192:8)
    at /app/node_modules/mongodb/lib/core/sdam/server.js:318:12
    at Object.callback (/app/node_modules/mongodb/lib/cmap/connection_pool.js:347:7)
    at processWaitQueue (/app/node_modules/mongodb/lib/cmap/connection_pool.js:470:23)
    at /app/node_modules/mongodb/lib/cmap/connection_pool.js:263:28
    at processTicksAndRejections (internal/process/task_queues.js:77:11)

What I tried:

  1. Await the close connection process when the app is killed, previously it’s using callback to close the connection. but even with await it takes around 6-7s for the connection to close so the app still receiving some request.
const gracefulExit = async (args) => {
  console.log('RECEIVED GRACEFUL EXIT', args);
  await mongoose.connection.close();
  console.info('Mongoose disconnected on app termination');
  1. increasing the poolSize to handle more socket connection, smaller heartbeatFrequencyMS to reduce the time between server goes down and when Mongoose emits ‘disconnected’, and connectTimeoutMS to wait before killing a socket due to inactivity .
const options = {
  useUnifiedTopology: !isLocal, // Needed for cloud run connection issues. Will throw a warning
  useNewUrlParser: true,
  useFindAndModify: false,
  useCreateIndex: true,
  poolSize: 10, // set the connection pool size
  // serverSelectionTimeoutMS: 5000, // set the server selection timeout
  heartbeatFrequencyMS: 5000, // set the heartbeat frequency
  connectTimeoutMS: 10000, // set the connection timeout
  1. reconnecting when querying if it’s disconnected to MongoDB so if it’s disconnected when I try to query, it will reconnect to Mongo first.
try {
      if (!filter) {
        throw 'GET ONE: No filter supplied';
      if(mongoose.connection.readyState !== 1) {
        console.log("reconnecting...", mongoose.connection.readyState)
        await connectDbAsync()
        console.log("reconnected", mongoose.connection.readyState)
      const result = await this.model.findOne(filter, fields, options);
      return result;
    } catch (e) {
      console.error('GET ONE ERROR:', e);
      throw e

but the error still persist. Any idea what’s wrong?
Thanks for your time!