Cache mongo serverless

connect.js

mongoose.Promise = global.Promise;

let cache = null;

const connect = async (database) => {
  if (cache) {
    logger.info('[DATABASE] Using cache');
    return Promise.resolve(cache);
  }

  return mongoose
    .connect(database, {
      useCreateIndex: true,
      useFindAndModify: false,
      useNewUrlParser: true,
      useUnifiedTopology: true,

      bufferCommands: false,
      bufferMaxEntries: 0,
    })
    .then((db) => {
      cache = db;
      return cache;
    });
};

const disconnect = async () => {
  await mongoose.disconnect();
};

mongoose.connection
  .on('connecting', () => logger.info('[DATABASE] Connecting database'))
  .on('connected', () => logger.info('[DATABASE] Database connected'))
  .on('disconnected', () => logger.warn('[DATABASE] Database disconnected'))
  .on('open', () => logger.info('[DATABASE] Connection opened'))
  .on('close', () => logger.warn('[DATABASE] Connection closed'))
  .on('error', (error) => logger.error(`[DATABASE] ${error.message}`));

export { connect, disconnect };

index.js

import serverless from 'serverless-http';
const handler = serverless(app);

export const start = async (event, context) => {
  context.callbackWaitsForEmptyEventLoop = false;

  const database = "youdb"

  await connect(database);

  const result = await handler(event, context);

  return result;
};