在 AWS Lambda 中使用 Mongoose

AWS Lambda 是一個熱門的服務，用於執行任意函數，而無需管理個別伺服器。在您的 AWS Lambda 函數中使用 Mongoose 很簡單。以下是一個範例函數，它會連線到 MongoDB 實例並尋找單一文檔。

const mongoose = require('mongoose');

let conn = null;

const uri = 'YOUR CONNECTION STRING HERE';

exports.handler = async function(event, context) {
  // Make sure to add this so you can re-use `conn` between function calls.
  // See https://www.mongodb.com/blog/post/serverless-development-with-nodejs-aws-lambda-mongodb-atlas
  context.callbackWaitsForEmptyEventLoop = false;

  // Because `conn` is in the global scope, Lambda may retain it between
  // function calls thanks to `callbackWaitsForEmptyEventLoop`.
  // This means your Lambda function doesn't have to go through the
  // potentially expensive process of connecting to MongoDB every time.
  if (conn == null) {
    conn = mongoose.createConnection(uri, {
      // and tell the MongoDB driver to not wait more than 5 seconds
      // before erroring out if it isn't connected
      serverSelectionTimeoutMS: 5000
    });

    // `await`ing connection after assigning to the `conn` variable
    // to avoid multiple function calls creating new connections
    await conn.asPromise();
    conn.model('Test', new mongoose.Schema({ name: String }));
  }

  const M = conn.model('Test');

  const doc = await M.findOne();
  console.log(doc);

  return doc;
};

連線輔助函式

上面的程式碼在單一 Lambda 函數中運作良好，但是如果您想在多個 Lambda 函數中重複使用相同的連線邏輯呢？您可以匯出以下函式。

const mongoose = require('mongoose');

let conn = null;

const uri = 'YOUR CONNECTION STRING HERE';

exports.connect = async function() {
  if (conn == null) {
    conn = mongoose.createConnection(uri, {
      serverSelectionTimeoutMS: 5000
    });

    // `await`ing connection after assigning to the `conn` variable
    // to avoid multiple function calls creating new connections
    await conn.asPromise();
  }

  return conn;
};

使用 mongoose.connect()

您也可以使用 mongoose.connect()，如此一來您就可以使用 mongoose.model() 來建立模型。

const mongoose = require('mongoose');

let conn = null;

const uri = 'YOUR CONNECTION STRING HERE';

exports.connect = async function() {
  if (conn == null) {
    conn = mongoose.connect(uri, {
      serverSelectionTimeoutMS: 5000
    }).then(() => mongoose);

    // `await`ing connection after assigning to the `conn` variable
    // to avoid multiple function calls creating new connections
    await conn;
  }

  return conn;
};