[Cloud DA] Serverless Framework with AWS

Serverless framework with AWS

Link to each sections

Table of Content:

Part 0: Serverless Project structure
Part 1: DynamoDB & ApiGateway
Part 2: Event Processing with WebSocket and DyanmoDB Stream
Part 3: Full Text searhc with ElasticSearch
Part 4: Fant out notification with SNS
Part 5: Auth with Auth0
Part 6: Using Lambda Middleware

Full content here

Serverless Project Structure

New configuration format

Please notice that the default structure of the TypeScript project has slightly changed, and it now contains serverless.ts file instead of serverless.yaml. You can still configure the project using YAML configuration as demonstrated in the course, but now the Serverless framework provides more configuration options, such as yml, json, js, and ts as described on serverless documentation. All functionalities work as well in the other available service file formats.

Serverless Plugins

Serverless framework's functionality can be extended using dozens of plugins developed for it. During the course we will use some of the most popular plugins, and you will see when and how to use them.

When you are looking for a plugin for your project you can use the plugins catalog on the Serverless Framework website.
If you can't find a plugin that would fit your needs, you can always implement your own. You can start with this guide if you want to explore this option.

Serverless Framework Events

If you want to learn more, you can find a full list of events that Serverless Framework supports in the official documentation. It provides examples for every event they support and describe all parameters it supports.

CloudFormation Resources

AWS documentation provides reference for all resource types CloudFormation support: AWS Resource and Property Types Reference.

Most of AWS resources can be created with CloudFormation, but in some rare cases you may encounter an AWS resource that is not supported by CloudFormation. In this case you would have to use AWS API, AWS CLI or AWS dashboard.

INSTALL

npm install -g serverless

CREATE PROJECT

serverless create --template aws-nodejs-typescript --path folder-name

INSTALL PLUGIN

npm install plugin-name --save-dev

DEPLOY PROJECT

sls deploy -v

Install serverless:
```
npm install -g serverless
```

Set up a new user in IAM named "serverless" and save the access key and secret key.

Configure serverless to use the AWS credentials you just set up:

sls config credentials --provider aws --key YOUR_ACCESS_KEY --secret YOUR_SECRET_KEY --profile IAM_USER_NAME

To create a serverless boilerplate project:

sls create --template aws-nodejs-typescript --path 10-udagram-app

Deploy the application
```
sls deploy -v
```

Part 1 DyanmoDB & ApiGateway

Build a Lambda function get data from DynamoDB:

src/lambda/http/getGroups.ts

import * as AWS from "aws-sdk";
import {
  APIGatewayProxyEvent,
  APIGatewayProxyHandler,
  APIGatewayProxyResult,
} from "aws-lambda";

const docClient = new AWS.DynamoDB.DocumentClient();
const groupTables = process.env.GROUPS_TABLE;

export const handler: APIGatewayProxyHandler = async (
  event: APIGatewayProxyEvent
): Promise<APIGatewayProxyResult> => {
const result = await docClient
    .scan({
      TableName: groupTables,
    })
    .promise();

  const items = result.Items;

  return {
    statusCode: 200,
    headers: {
      "Access-Control-Allow-Origin": "*",
    },
    body: JSON.stringify({
      items,
    }),
  };
};

serverless.yml:

service:
  name: serverless-udagram-app

plugins:
  - serverless-webpack

provider:
  name: aws
  runtime: nodejs14.x

  stage: ${opt:stage, 'dev'}
  region: ${opt:region, 'us-east-1'}

  environment:
    GROUPS_TABLE: Groups-${self:provider.stage}

  iamRoleStatements:
    - Effect: Allow
      Action:
        - dynamodb:Scan
      Resource: arn:aws:dynamodb:${self:provider.region}:*:table/${self:provider.environment.GROUPS_TABLE}

functions:
  GetGroups:
    handler: src/lambda/http/getGroups.handler
    events:
      - http:
          method: get
          path: groups
          cors: true

resources:
  Resources:
    GroupsDynamoDBTable:
      Type: AWS::DynamoDB::Table
      Properties:
        AttributeDefinitions:
          - AttributeName: id
            AttributeType: S
        KeySchema:
          - AttributeName: id
            KeyType: HASH
        BillingMode: PAY_PER_REQUEST
        TableName: ${self:provider.environment.GROUPS_TABLE}

Validate request in ApiGateway

Refer to: https://www.cnblogs.com/Answer1215/p/14774552.html

Query in Node.js

const docClient = new AWS.DynamoDB.DocumentClient()

 const result = await docClient.query({
   TableName: 'GameScore',
   KeyConditionExpression: 'GameId = :gameId',
   ExpressionAttributeValues: {
     ':gameId': '10'
   }
 }).promise()

 const items = result.Items

Path parameter

functions:
    GetOrders:
      handler: src/images.handler
      events:
        - http:
            method: get
            path: /groups/{groupId}/images

export.handler = async (event) => {
  const grouId = event.pathParameters.groupId;
  ...
}

Add indexes

serverless.yml

service:
  name: serverless-udagram-app

plugins:
  - serverless-webpack

provider:
  name: aws
  runtime: nodejs14.x

  stage: ${opt:stage, 'dev'}
  region: ${opt:region, 'us-east-1'}

  environment:
    GROUPS_TABLE: Groups-${self:provider.stage}
    IMAGES_TABLE: Images-${self:provider.stage}
    IMAGE_ID_INDEX: ImageIdIndex

  iamRoleStatements:
    - Effect: Allow
      Action:
        - dynamodb:Query
      Resource: arn:aws:dynamodb:${self:provider.region}:*:table/${self:provider.environment.IMAGES_TABLE}/index/${self:provider.environment.IMAGE_ID_INDEX}
    - Effect: Allow
      Action:
        - dynamodb:Query
        - dynamodb:PutItem
      Resource: arn:aws:dynamodb:${self:provider.region}:*:table/${self:provider.environment.IMAGES_TABLE}
    - Effect: Allow
      Action:
        - dynamodb:Scan
        - dynamodb:PutItem
        - dynamodb:GetItem
      Resource: arn:aws:dynamodb:${self:provider.region}:*:table/${self:provider.environment.GROUPS_TABLE}

functions:
  CreateImage:
    handler: src/lambda/http/createImage.handler
    events:
      - http:
          method: post
          path: groups/{groupId}/images
          cors: true
          reqValidatorName: RequestBodyValidator
          request:
            schema:
              application/json: ${file(models/create-image-request.json)}
  GetImage:
    handler: src/lambda/http/getImage.handler
    events:
      - http:
          method: get
          path: images/{imageId}
          cors: true
  GetImages:
    handler: src/lambda/http/getImages.handler
    events:
      - http:
          method: get
          path: group/{groupId}/images
          cors: true
  GetGroups:
    handler: src/lambda/http/getGroups.handler
    events:
      - http:
          method: get
          path: groups
          cors: true
  CreateGroup:
    handler: src/lambda/http/createGroup.handler
    events:
      - http:
          method: post
          path: groups
          cors: true
          ## do the validation in api gateway
          reqValidatorName: RequestBodyValidator
          request:
            schema:
              application/json: ${file(models/create-group-request.json)}

resources:
  Resources:
    ImagesDynamoDBTable:
      Type: AWS::DynamoDB::Table
      Properties:
        TableName: ${self:provider.environment.IMAGES_TABLE}
        BillingMode: PAY_PER_REQUEST
        KeySchema:
          - AttributeName: groupId
            KeyType: HASH
          - AttributeName: timestamp
            KeyType: RANGE
        AttributeDefinitions:
          - AttributeName: groupId
            AttributeType: S
          - AttributeName: timestamp
            AttributeType: S
          - AttributeName: imageId
            AttributeType: S
        GlobalSecondaryIndexes:
          - IndexName: ${self:provider.environment.IMAGE_ID_INDEX}
            KeySchema:
              - AttributeName: imageId
                KeyType: HASH
            ## Copy all the attrs to the new GSI table
            Projection:
              ProjectionType: ALL

    GroupsDynamoDBTable:
      Type: AWS::DynamoDB::Table
      Properties:
        AttributeDefinitions:
          - AttributeName: id
            AttributeType: S
        KeySchema:
          - AttributeName: id
            KeyType: HASH
        BillingMode: PAY_PER_REQUEST
        TableName: ${self:provider.environment.GROUPS_TABLE}

const docClient = new AWS.DynamoDB.DocumentClient();
const imagesTable = process.env.IMAGES_TABLE;
const imageIdIndex = process.env.IMAGE_ID_INDEX;

export const handler: APIGatewayProxyHandler = async (
  event: APIGatewayProxyEvent
): Promise<APIGatewayProxyResult> => {
  const imageId = event.pathParameters.imageId;
  const result = await docClient
    .query({
      TableName: imagesTable,
      IndexName: imageIdIndex,
      KeyConditionExpression: "imageId= :imageId",
      ExpressionAttributeValues: {
        ":imageId": imageId,
      },
    })
    .promise();

Part 2 Event Processing

In section 2.1, what we will do is

User Uplaod a image to S3 bucket
Then S3 bucket will fire an event about file uploaded to lambda function
Lambda function will send notification vai API Gateway to tell users that one image has been uploaded

Upload a image to S3 bucket

Ref: Using Pre-signed url pattern for cmd use cases

Ref: How Pre-signed url work

In short: When user load a image

Request comes to API Gateway
API Gateway route event to lambda function to generate a Pre-signed URL return to Client
Lambda function needs to have the permissions to write to S3 Bucket
Client can use that Pre-signed URL to upload image to S3.

Define the resource in serverless.yml:

Define a name for S3 bucekt:

  environment:
    ..
    IMAGES_S3_BUCKET: zhentiw-serverless-udagram-images-${self:provider.stage}

Define resouce for S3 and bucket policy which allow anybody to read from S3:

resources:
  Resources:
    ## S3 bueckt which store images
    AttachmentsBucket:
      Type: AWS::S3::Bucket
      Properties:
        BucketName: ${self:provider.environment.IMAGES_S3_BUCKET}
        CorsConfiguration:
          CorsRules:
            - AllowedMethods:
                - GET
                - PUT
                - POST
                - DELETE
                - HEAD
              AllowedHeaders:
                - "*"
              AllowedOrigins:
                - "*"
              MaxAge: 3000 # 50 hours
    BucketPolicy:
      Type: AWS::S3::BucketPolicy
      Properties:
        Bucket: !Ref AttachmentsBucket
        PolicyDocument:
          Id: MyPolicy
          Version: "2012-10-17"
          Statement:
            - Sid: PublicReadForGetBucketObjects
              Effect: Allow
              Principal: "*"
              Action: "s3:GetObject"
              Resource: "arn:aws:s3:::${self:provider.environment.IMAGES_S3_BUCKET}/*"

Generate a Pre-sign url:

Define a expriation time for pre-signed url:

  environment:
    ...
    IMAGES_S3_BUCKET: zhentiw-serverless-udagram-images-${self:provider.stage}
    SIGNED_URL_EXPIRATION: 300

Add Permission to Lambda for S3:

  iamRoleStatements:
    - Effect: Allow
      Action:
        - s3:PutObject
        - s3:GetObject
      Resource: arn:aws:s3:::${self:provider.environment.IMAGES_S3_BUCKET}/*

Define Lambda funtions:

functions:
  CreateImage:
    handler: src/lambda/http/createImage.handler
    events:
      - http:
          method: post
          path: groups/{groupId}/images
          cors: true
          reqValidatorName: RequestBodyValidator
          request:
            schema:
              application/json: ${file(models/create-image-request.json)}

Lambda code: src/lambda/http/createImages.ts:

import { v4 as uuidv4 } from "uuid";
import "source-map-support/register";
import * as AWS from "aws-sdk";
import {
  APIGatewayProxyEvent,
  APIGatewayProxyHandler,
  APIGatewayProxyResult,
} from "aws-lambda";

const docClient = new AWS.DynamoDB.DocumentClient();
const groupTables = process.env.GROUPS_TABLE;
const imagesTables = process.env.IMAGES_TABLE;
const bucketName = process.env.IMAGES_S3_BUCKET;
const urlExpiration = process.env.SIGNED_URL_EXPIRATION;

const s3 = new AWS.S3({
  signatureVersion: "v4",
});

function getPreSignedUrl(imageId) {
  return s3.getSignedUrl("putObject", {
    Bucket: bucketName,
    Key: imageId,
    Expires: parseInt(urlExpiration, 10),
  });
}
export const handler: APIGatewayProxyHandler = async (
  event: APIGatewayProxyEvent
): Promise<APIGatewayProxyResult> => {
  console.log("Processing event: ", event);
  const imageId = uuidv4();
  const groupId = event.pathParameters.groupId;
  const parsedBody = JSON.parse(event.body);
  const isGroupExist = await groupExists(groupId);

  if (!isGroupExist) {
    return {
      statusCode: 404,
      headers: {
        "Access-Control-Allow-Origin": "*",
      },
      body: JSON.stringify({
        error: "Group does not exist",
      }),
    };
  }

  const newItem = {
    imageId,
    groupId,
    timestamp: new Date().toISOString(),
    ...parsedBody,
    imageUrl: `https://${bucketName}.s3.amazonaws.com/${imageId}`,
  };

  await docClient
    .put({
      TableName: imagesTables,
      Item: newItem,
    })
    .promise();

  const url = getPreSignedUrl(imageId);

  return {
    statusCode: 201,
    headers: {
      "Access-Control-Allow-Origin": "*",
    },
    body: JSON.stringify({
      newItem,
      uploadUrl: url,
    }),
  };
};

async function groupExists(groupId) {
  const result = await docClient
    .get({
      TableName: groupTables,
      Key: {
        id: groupId,
      },
    })
    .promise();
  console.log("Get group", result);
  return !!result.Item;
}

S3 Event

We need to create 2 resources

S3 should config Notification to Lambda function
S3 should have persmission to call Lambda function

Config Notification for S3 send to Lambda

Here is a configuration snippet that can be used to subscribe to S3 events:

functions:
  process:
    handler: file.handler
    events:
      - s3: bucket-name
        event: s3:ObjectCreated:*
        rules:
            - prefix: images/
            - suffix: .png

But there are some small problems with Event sent by S3 in serverless, it will re-create a s3 bucket with the same name cause the operation failed.

So here is how we should do it as work around:

Define function for Lambda

functions:
  ...
  SendUploadNotification:
    handler: src/lambda/s3/sendNotification.handler

Add noticifation

resources:
  Resources:
    AttachmentsBucket:
      Type: AWS::S3::Bucket
      Properties:
        BucketName: ${self:provider.environment.IMAGES_S3_BUCKET}
        NotificationConfiguration:
          LambdaConfigurations:
            - Event: s3:ObjectCreated:*
              ## <function_name>LambdaFunction.Arn
              Function: !GetAtt SendUploadNotificationLambdaFunction.Arn
        CorsConfiguration:
          CorsRules:
            - AllowedMethods:
                - GET
                - PUT
                - POST
                - DELETE
                - HEAD
              AllowedHeaders:
                - "*"
              AllowedOrigins:
                - "*"
              MaxAge: 3000 # 50 hours

Allow S3 to send Notification to Lambda:

resources:
  Resources:
    ...
    SendUploadNotificationPermission:
      Type: AWS::Lambda::Permission
      Properties:
        Action: lambda:InvokeFunction
        FunctionName: !Ref SendUploadNotificationLambdaFunction
        Principal: s3.amazonaws.com
        SourceAccount: !Ref "AWS::AccountId"
        SourceArn: arn:aws:s3:::${self:provider.environment.IMAGES_S3_BUCKET}

Lambda function:

src/lambda/s3/sendNotification.ts

import { S3Handler, S3Event } from "aws-lambda";
import "source-map-support/register";

export const handler: S3Handler = async (event: S3Event) => {
  for (const record of event.Records) {
    const key = record.s3.object.key;
    console.log("Processing S3 item with key: " + key);
  }
};

For now, we just need to verify that Lambda function can get notfication from S3.

Now, what we have done from the roundmap:

WebSocket

In section 2.2, what we will do is

Send notification about a image has been uploaded to clinet by websockets

Websocket Refer: https://www.cnblogs.com/Answer1215/p/14782429.html

Add Env var:

  environment:
    ...
    CONNECTIONS_TABLE: Socket-connections-${self:provider.stage}
    ...

Add iam permission to `scan`, `PutItem` and `DeleteItem`:

  iamRoleStatements:
   ...
    - Effect: Allow
      Action:
        - dynamodb:Scan
        - dynamodb:PutItem
        - dynamodb:DeleteItem
      Resource: arn:aws:dynamodb:${self:provider.region}:*:table/${self:provider.environment.CONNECTIONS_TABLE}

Add two Lambda functions to handle Connect socket and Disconnect socket events:
Once websocket connect to ApiGateway, we want to save `connectionId` to DynamoDB. Once sockets disconnect from API Gateway, we delete the connectionId from DynamoDB.

src/lambda/websockets/connect.ts

import * as AWS from "aws-sdk";
import {
  APIGatewayProxyEvent,
  APIGatewayProxyHandler,
  APIGatewayProxyResult,
} from "aws-lambda";

const docClient = new AWS.DynamoDB.DocumentClient();
const connectionsTable = process.env.CONNECTIONS_TABLE;

export const handler: APIGatewayProxyHandler = async (
  event: APIGatewayProxyEvent
): Promise<APIGatewayProxyResult> => {
  console.log("Websocket connect: ", event);
  const timestamp = new Date().toISOString();
  const connectionId = event.requestContext.connectionId;
  const item = {
    id: connectionId,
    timestamp,
  };
  await docClient
    .put({
      TableName: connectionsTable,
      Item: item,
    })
    .promise();

  return {
    statusCode: 200,
    headers: {
      "Access-Control-Allow-Origin": "*",
    },
    body: "",
  };
};

src/lambda/websockets/disconnect.ts

import * as AWS from "aws-sdk";
import {
  APIGatewayProxyEvent,
  APIGatewayProxyHandler,
  APIGatewayProxyResult,
} from "aws-lambda";

const docClient = new AWS.DynamoDB.DocumentClient();
const connectionsTable = process.env.CONNECTIONS_TABLE;

export const handler: APIGatewayProxyHandler = async (
  event: APIGatewayProxyEvent
): Promise<APIGatewayProxyResult> => {
  console.log("Websocket connect: ", event);
  const connectionId = event.requestContext.connectionId;
  const key = {
    id: connectionId,
  };
  await docClient
    .delete({
      TableName: connectionsTable,
      Key: key,
    })
    .promise();

  return {
    statusCode: 200,
    body: "",
  };
};

Send Notifiction once file was uploaded

What we need to do:

Send Websocket messages on a file upload
Will use a list of connections stored in DynamoDB

Add functions for Lambda:

  SendUploadNotification:
    handler: src/lambda/s3/sendNotification.handler
    environment:
      STAGE: ${self:provider.stage}
      API_ID:
        Ref: WebsocketsApi

It has inline `environment` which will only being used for this function.

import { S3Handler, S3Event } from "aws-lambda";

import "source-map-support/register";
import * as AWS from "aws-sdk";

const docClient = new AWS.DynamoDB.DocumentClient();
const connectionsTable = process.env.CONNECTIONS_TABLE;
const stage = process.env.STAGE;
const apiID = process.env.API_ID;

const connectionParams = {
  apiVersion: "2010-11-29",
  endpoint: `${apiID}.execute-api.us-east-1.amazonaws.com/${stage}`,
};

const apiGateway = new AWS.ApiGatewayManagementApi(connectionParams);

async function processS3Event(s3Event: S3Event) {
  for (const record of s3Event.Records) {
    const key = record.s3.object.key;
    console.log("Processing S3 item with key: ", key);
    const connections = await docClient
      .scan({
        TableName: connectionsTable,
      })
      .promise();

    const payload = {
      imageId: key,
    };

    for (const connection of connections.Items) {
      const connectionId = connection.id;
      await sendMessagedToClient(connectionId, payload);
    }
  }
}

async function sendMessagedToClient(connectionId, payload) {
  try {
    console.log("Sending message to a connection", connectionId);
    await apiGateway
      .postToConnection({
        ConnectionId: connectionId,
        Data: JSON.stringify(payload),
      })
      .promise();
  } catch (e) {
    if (e.statusCode === 410) {
      console.log("Stale connection");
      await docClient
        .delete({
          TableName: connectionsTable,
          Key: {
            id: connectionId,
          },
        })
        .promise();
    }
  }
}

export const handler: S3Handler = async (event: S3Event) => {
  await processS3Event(event)
};

Becasuse API Gateway holds a connection between client and websocket.

We send message to Api gatway by `postToConnection` method.

Part 3 Full-Text Search

ElasticSearch, Sync data between DynamoDB and ElasticSearch

Refer: https://www.cnblogs.com/Answer1215/p/14783470.html

Enable DynamoDB Stream

serverless.yml:

service:
  name: serverless-udagram-app

plugins:
  - serverless-webpack

provider:
  name: aws
  runtime: nodejs14.x

  stage: ${opt:stage, 'dev'}
  region: ${opt:region, 'us-east-1'}

  environment:
    GROUPS_TABLE: Groups-${self:provider.stage}
    IMAGES_TABLE: Images-${self:provider.stage}
    CONNECTIONS_TABLE: Socket-connections-${self:provider.stage}
    IMAGE_ID_INDEX: ImageIdIndex
    IMAGES_S3_BUCKET: zhentiw-serverless-udagram-images-${self:provider.stage}
    SIGNED_URL_EXPIRATION: 300

  iamRoleStatements:
    - Effect: Allow
      Action:
        - s3:PutObject
        - s3:GetObject
      Resource: arn:aws:s3:::${self:provider.environment.IMAGES_S3_BUCKET}/*
    - Effect: Allow
      Action:
        - dynamodb:Query
      Resource: arn:aws:dynamodb:${self:provider.region}:*:table/${self:provider.environment.IMAGES_TABLE}/index/${self:provider.environment.IMAGE_ID_INDEX}
    - Effect: Allow
      Action:
        - dynamodb:Query
        - dynamodb:PutItem
      Resource: arn:aws:dynamodb:${self:provider.region}:*:table/${self:provider.environment.IMAGES_TABLE}
    - Effect: Allow
      Action:
        - dynamodb:Scan
        - dynamodb:PutItem
        - dynamodb:GetItem
      Resource: arn:aws:dynamodb:${self:provider.region}:*:table/${self:provider.environment.GROUPS_TABLE}
    - Effect: Allow
      Action:
        - dynamodb:Scan
        - dynamodb:PutItem
        - dynamodb:DeleteItem
      Resource: arn:aws:dynamodb:${self:provider.region}:*:table/${self:provider.environment.CONNECTIONS_TABLE}

functions:
  CreateImage:
    handler: src/lambda/http/createImage.handler
    events:
      - http:
          method: post
          path: groups/{groupId}/images
          cors: true
          reqValidatorName: RequestBodyValidator
          request:
            schema:
              application/json: ${file(models/create-image-request.json)}
  GetImage:
    handler: src/lambda/http/getImage.handler
    events:
      - http:
          method: get
          path: images/{imageId}
          cors: true
  GetImages:
    handler: src/lambda/http/getImages.handler
    events:
      - http:
          method: get
          path: group/{groupId}/images
          cors: true
  GetGroups:
    handler: src/lambda/http/getGroups.handler
    events:
      - http:
          method: get
          path: groups
          cors: true
  CreateGroup:
    handler: src/lambda/http/createGroup.handler
    events:
      - http:
          method: post
          path: groups
          cors: true
          ## do the validation in api gateway
          reqValidatorName: RequestBodyValidator
          request:
            schema:
              application/json: ${file(models/create-group-request.json)}
  SendUploadNotification:
    handler: src/lambda/s3/sendNotification.handler

  ConnectHandler:
    handler: src/lambda/websockets/connect.handler
    events:
      - websocket:
          route: $connect
  DisconnectHandler:
    handler: src/lambda/websockets/disconnect.handler
    events:
      - websocket:
          route: $disconnect

  SyncWithElasticsearch:
    handler: src/lambda/dynamodb/elasticsearchSync.handler
    events:
      - stream:
          type: dynamodb
          arn: !GetAtt ImagesDynamoDBTable.StreamArn

resources:
  Resources:
    AttachmentsBucket:
      Type: AWS::S3::Bucket
      Properties:
        BucketName: ${self:provider.environment.IMAGES_S3_BUCKET}
        NotificationConfiguration:
          LambdaConfigurations:
            - Event: s3:ObjectCreated:*
              ## <function_name>LambdaFunction.Arn
              Function: !GetAtt SendUploadNotificationLambdaFunction.Arn
        CorsConfiguration:
          CorsRules:
            - AllowedMethods:
                - GET
                - PUT
                - POST
                - DELETE
                - HEAD
              AllowedHeaders:
                - "*"
              AllowedOrigins:
                - "*"
              MaxAge: 3000 # 50 hours
    BucketPolicy:
      Type: AWS::S3::BucketPolicy
      Properties:
        Bucket: !Ref AttachmentsBucket
        PolicyDocument:
          Id: MyPolicy
          Version: "2012-10-17"
          Statement:
            - Sid: PublicReadForGetBucketObjects
              Effect: Allow
              Principal: "*"
              Action: "s3:GetObject"
              Resource: "arn:aws:s3:::${self:provider.environment.IMAGES_S3_BUCKET}/*"
    ConnectionsDynamoDBTable:
      Type: AWS::DynamoDB::Table
      Properties:
        TableName: ${self:provider.environment.CONNECTIONS_TABLE}
        BillingMode: PAY_PER_REQUEST
        AttributeDefinitions:
          - AttributeName: id
            AttributeType: S
        KeySchema:
          - AttributeName: id
            KeyType: HASH
    ImagesDynamoDBTable:
      Type: AWS::DynamoDB::Table
      Properties:
        TableName: ${self:provider.environment.IMAGES_TABLE}
        BillingMode: PAY_PER_REQUEST
        StreamSpecification:
          StreamViewType: NEW_IMAGE
        KeySchema:
          - AttributeName: groupId
            KeyType: HASH
          - AttributeName: timestamp
            KeyType: RANGE
        AttributeDefinitions:
          - AttributeName: groupId
            AttributeType: S
          - AttributeName: timestamp
            AttributeType: S
          - AttributeName: imageId
            AttributeType: S
        GlobalSecondaryIndexes:
          - IndexName: ${self:provider.environment.IMAGE_ID_INDEX}
            KeySchema:
              - AttributeName: imageId
                KeyType: HASH
            ## Copy all the attrs to the new GSI table
            Projection:
              ProjectionType: ALL
    SendUploadNotificationPermission:
      Type: AWS::Lambda::Permission
      Properties:
        Action: lambda:InvokeFunction
        FunctionName: !Ref SendUploadNotificationLambdaFunction
        Principal: s3.amazonaws.com
        SourceAccount: !Ref "AWS::AccountId"
        SourceArn: arn:aws:s3:::${self:provider.environment.IMAGES_S3_BUCKET}

    GroupsDynamoDBTable:
      Type: AWS::DynamoDB::Table
      Properties:
        AttributeDefinitions:
          - AttributeName: id
            AttributeType: S
        KeySchema:
          - AttributeName: id
            KeyType: HASH
        BillingMode: PAY_PER_REQUEST
        TableName: ${self:provider.environment.GROUPS_TABLE}

We enabled "DynamoDB Stream" for Images table, whenever there is an update for the table, a stream will be fired and catch by a lambda function.

Add Elasticsearch resources

    ImagesSearch:
      Type: AWS::Elasticsearch::Domain
      Properties:
        ElasticsearchVersion: "6.7"
        DomainName: images-search-${self:provider.stage}
        ElasticsearchClusterConfig:
          DedicatedMasterEnabled: false
          InstanceCount: 1
          ZoneAwarenessEnabled: false
          InstanceType: t2.small.elasticsearch
        EBSOptions:
          EBSEnabled: true
          Iops: 0
          VolumeSize: 10
          VolumeType: "gp2"
        AccessPolicies:
          Version: "2012-10-17"
          Statement:
            - Effect: Allow
              Principal:
                AWS: !Sub "arn:aws:sts::${AWS::AccountId}:assumed-role/${self:service}-${self:provider.stage}-${self:provider.region}-lambdaRole/serverless-udagram-app-${self:provider.stage}-SyncWithElasticsearch"
              Action: es:ESHttp*
              Resource: !Sub "arn:aws:es:${self:provider.region}:${AWS::AccountId}:domain/images-search-${self:provider.stage}/*"
            - Effect: Allow
              Principal:
                AWS: "*"
              Action: es:ESHttp*
              Condition:
                IpAddress:
                  aws:SourceIp:
                    - "<YOUR_IP_ADDRESS>/32"
              Resource: !Sub "arn:aws:es:${self:provider.region}:${AWS::AccountId}:domain/images-search-${self:provider.stage}/*"

After Deployed, Open Kibana, config index:

Part 4 SNS

What if we want to have two event handlers for the same S3 bucket

Send a WebSocket notification
Resize an image

Looks like the pic:

But actually we CANNOT do this.

Because S3 allows only one notification target.

We need to use a different service to

receive one event
Broadcast it to multiple targets

We will use SNS for this.

SNS is a service to send messages to other services.

It has two main concepts:

Publishers - publish messages
Subscribers - consume incoming messages

Publishers and subscribers communicate via topics:

A publisher publish a message to a topic
A subscriber receives a message if it is subscribed to a topic
One topic can have many subscribers
Subscribers can use various protocols: Lambda, HTTP, email, SMS, etc.

Add a `custom` which can be used as environment in template, but won't be used at lambda function:

custom:
  topicName: ImagesTopic-${self:provider.stage}

Then for the lambda function which send notification to clinets, previously, we send notfiction when S3 upload event fire.

Now we need to change it listen SNS topic:

functions:
    SendUploadNotification:
      handler: src/lambda/s3/sendNotification.handler
      environment:
        STAGE: ${self:provider.stage}
        API_ID:
          Ref: WebsocketsApi
      events:
        - sns:
            arn:
              Fn::Join:
                - ":"
                - - arn:aws:sns
                  - Ref: AWS::Region
                  - Ref: AWS::AccountId
                  - ${self:custom.topicName}
            topicName: ${self:custom.topicName}

Add topic resource and topic policy:

    ImagesTopic:
      Type: AWS::SNS::Topic
      Properties:
        DisplayName: Image bucket topic
        TopicName: ${self:custom.topicName}
    SNSTopicPolicy:
      Type: AWS::SNS::TopicPolicy
      Properties:
        PolicyDocument:
          Version: "2012-10-17"
          Statement:
            - Effect: Allow
              Principal:
                AWS: "*"
              Action: sns:Publish
              Resource: !Ref ImagesTopic
              Condition:
                ArnLike:
                  Aws:SourceArn: arn:aws:s3:::${self:provider.environment.IMAGES_S3_BUCKET}
        Topics:
          - !Ref ImagesTopic

Update Lambda function:

import { S3Event, SNSHandler, SNSEvent } from "aws-lambda";

import "source-map-support/register";
import * as AWS from "aws-sdk";

const docClient = new AWS.DynamoDB.DocumentClient();
const connectionsTable = process.env.CONNECTIONS_TABLE;
const stage = process.env.STAGE;
const apiID = process.env.API_ID;

const connectionParams = {
  apiVersion: "2018-11-29",
  endpoint: `${apiID}.execute-api.us-east-1.amazonaws.com/${stage}`,
};

const apiGateway = new AWS.ApiGatewayManagementApi(connectionParams);

export const handler: SNSHandler = async (event: SNSEvent) => {
  console.log("Processing SNS event", JSON.stringify(event));
  for (const snsRecord of event.Records) {
    const s3EventStr = snsRecord.Sns.Message;
    console.log("Processing S3 event", s3EventStr);
    const s3Event = JSON.parse(s3EventStr);
    await processS3Event(s3Event);
  }
};

async function processS3Event(s3Event: S3Event) {
  for (const record of s3Event.Records) {
    const key = record.s3.object.key;
    console.log("Processing S3 item with key: ", key);
    const connections = await docClient
      .scan({
        TableName: connectionsTable,
      })
      .promise();

    const payload = {
      imageId: key,
    };

    for (const connection of connections.Items) {
      const connectionId = connection.id;
      await sendMessagedToClient(connectionId, payload);
    }
  }
}

async function sendMessagedToClient(connectionId, payload) {
  try {
    console.log("Sending message to a connection", connectionId);
    await apiGateway
      .postToConnection({
        ConnectionId: connectionId,
        Data: JSON.stringify(payload),
      })
      .promise();
  } catch (e) {
    if (e.statusCode === 410) {
      console.log("Stale connection");
      await docClient
        .delete({
          TableName: connectionsTable,
          Key: {
            id: connectionId,
          },
        })
        .promise();
    }
  }
}

Part 5 Auth

Refer: https://www.cnblogs.com/Answer1215/p/14798866.html

We want to store the Auth0 Secret into AWS Secret Manager.

Add Permission for IAM user:

When doing Auth authorization, what we want to do is

Get secrect object stored in ASM
Then get that field which contains our actual secret value
Do the validation with JWT

Update code in Lambda: src/lambda/auth/auth0Authorization.ts

import {
  CustomAuthorizerEvent,
  CustomAuthorizerHandler,
  CustomAuthorizerResult,
} from "aws-lambda";
import * as AWS from "aws-sdk";
import { verify } from "jsonwebtoken";
import { JwtToken } from "../../auth/JwtToken";

const secretId = process.env.AUTH_0_SECRET_ID;
const secretField = process.env.AUTH_0_SECRET_FIELD;

let client = new AWS.SecretsManager();
// cache secrect if a Lambda instance is reused
let cachedSecret: string;

export const handler: CustomAuthorizerHandler = async (
  event: CustomAuthorizerEvent
): Promise<CustomAuthorizerResult> => {
  try {
    const decodedToken = await verifyToken(event.authorizationToken);
    console.log("User was authorized", decodedToken);
    return {
      // unqiue token id for user
      principalId: decodedToken.sub,
      policyDocument: {
        Version: "2012-10-17",
        Statement: [
          {
            Action: "execute-api:Invoke",
            Effect: "Allow",
            Resource: "*",
          },
        ],
      },
    };
  } catch (err) {
    console.log("User was not authorized", err.message);
    return {
      principalId: "user",
      policyDocument: {
        Version: "2012-10-17",
        Statement: [
          {
            Action: "execute-api:Invoke",
            Effect: "Deny",
            Resource: "*",
          },
        ],
      },
    };
  }
};

async function verifyToken(authHeader: string): Promise<JwtToken> {
  console.log("authHeader", authHeader);
  if (!authHeader) {
    throw new Error("No authorization header");
  }

  if (authHeader.toString().indexOf("bearer") > -1) {
    throw new Error("Invalid authorization header");
  }

  const splits = authHeader.split(" ");
  const token = splits[1];
  console.log("token", token);

  const secrectObject = await getSecret();
  const secret = secrectObject[secretField];

  // use JWT to verify the token with the secret
  return verify(token, secret) as JwtToken;
  // A request has been authorized.
}

async function getSecret() {
  // using the secret id we have in KMS to get the secret object
  // which will contain the secret value we want to use with JWT token
  if (cachedSecret) {
    return cachedSecret;
  }

  const data = await client
    .getSecretValue({
      SecretId: secretId,
    })
    .promise();

  cachedSecret = data.SecretString;
  return JSON.parse(cachedSecret);
}

Add resouces:

    AUTH_SECRET_ID: AuthZeroSercet-${self:provider.stage}
    AUTH_SECRET_FIELD: authSecret

resources:
  Resources:
    KMSKey:
      Type: AWS::KMS::Key
      Properties:
        KeyPolicy:
          Version: "2012-10-17"
          Id: key-default-1
          Statement:
            - Sid: Allow administration of the key
              Effect: Allow
              Principal:
                AWS:
                  Fn::Join:
                    - ":"
                    - - "arn:aws:iam:"
                      - Ref: AWS::AccountId
                      - "root"
              Action:
                - "kms:*"
              Resource: "*"
    KMSAlias:
      Type: AWS::KMS::Alias
      Properties:
        AliasName: alias/authKey-${self:provider.stage}
        TargetKeyId: !Ref KMSKey
    AuthZeroSecret:
      Type: AWS::SecretsManager::Secret
      Properties:
        Name: ${self:provider.environment.AUTH_SECRET_ID}
        Description: AuthZero Secret
        KmsKeyId: !Ref KMSKey
    GatewayResponseDefault4XX:

Add permission for Lambda:

    - Effect: Allow
      Action:
        - secretsmanager:GetSecretValue
      Resource: !Ref AuthZeroSecret
    - Effect: Allow
      Action:
        - kms:Decrypt
      Resource: !GetAtt KMSKey.Arn

Add Auth to endpoint:

 CreateImage:
    handler: src/lambda/http/createImage.handler
    events:
      - http:
          method: post
          path: groups/{groupId}/images
          cors: true
          authorizer: Auth
          reqValidatorName: RequestBodyValidator
          request:
            schema:
              application/json: ${file(models/create-image-request.json)}

Also need to add Auth0 sercet into AWS Sercet Manager:

For storing sercet in AWS, there are two options, what we choose is Sercet manager, another one can be used is SSM parameter store:

Part 7: Using Lamba Middleware

Refer: https://www.cnblogs.com/Answer1215/p/14804275.html

Use Middy middleware to load secrets
Will read secrets from Secrets Manager
Caches them so a Lambda could re-use-them
- Configure caching duration

Install middy lib.

Using Cors:

// createImage.ts

import { v4 as uuidv4 } from "uuid";
import "source-map-support/register";
import * as AWS from "aws-sdk";
import { APIGatewayProxyEvent, APIGatewayProxyResult } from "aws-lambda";
import * as middy from "middy";
import { cors } from "middy/middlewares";

const docClient = new AWS.DynamoDB.DocumentClient();
const groupTables = process.env.GROUPS_TABLE;
const imagesTables = process.env.IMAGES_TABLE;
const bucketName = process.env.IMAGES_S3_BUCKET;
const urlExpiration = process.env.SIGNED_URL_EXPIRATION;

const s3 = new AWS.S3({
  signatureVersion: "v4",
});

function getPreSignedUrl(imageId) {
  return s3.getSignedUrl("putObject", {
    Bucket: bucketName,
    Key: imageId,
    Expires: parseInt(urlExpiration, 10),
  });
}
export const handler = middy(
  async (event: APIGatewayProxyEvent): Promise<APIGatewayProxyResult> => {
    console.log("Processing event: ", event);
    const imageId = uuidv4();
    const groupId = event.pathParameters.groupId;
    const parsedBody = JSON.parse(event.body);
    const isGroupExist = await groupExists(groupId);

    if (!isGroupExist) {
      return {
        statusCode: 404,
        body: JSON.stringify({
          error: "Group does not exist",
        }),
      };
    }

    const newItem = {
      imageId,
      groupId,
      timestamp: new Date().toISOString(),
      ...parsedBody,
      imageUrl: `https://${bucketName}.s3.amazonaws.com/${imageId}`,
    };

    await docClient
      .put({
        TableName: imagesTables,
        Item: newItem,
      })
      .promise();

    const url = getPreSignedUrl(imageId);

    return {
      statusCode: 201,
      body: JSON.stringify({
        newItem,
        uploadUrl: url,
      }),
    };
  }
);

async function groupExists(groupId) {
  const result = await docClient
    .get({
      TableName: groupTables,
      Key: {
        id: groupId,
      },
    })
    .promise();
  console.log("Get group", result);
  return !!result.Item;
}

handler.use(cors({ credentials: true }));

Using SecretManager:

import { CustomAuthorizerEvent, CustomAuthorizerResult } from "aws-lambda";
import { verify } from "jsonwebtoken";
import { JwtToken } from "../../auth/JwtToken";

import * as middy from "middy";
import { secretsManager } from "middy/middlewares";

const secretId = process.env.AUTH_SECRET_ID;
const secretField = process.env.AUTH_SECRET_FIELD;

export const handler = middy(
  async (
    event: CustomAuthorizerEvent,
    // middy will store the result in the context
    context
  ): Promise<CustomAuthorizerResult> => {
    try {
      const decodedToken = verifyToken(
        event.authorizationToken,
        context["AUTH0_SECRET"][secretField]
      );
      console.log("User was authorized", decodedToken);
      return {
        // unqiue token id for user
        principalId: decodedToken.sub,
        policyDocument: {
          Version: "2012-10-17",
          Statement: [
            {
              Action: "execute-api:Invoke",
              Effect: "Allow",
              Resource: "*",
            },
          ],
        },
      };
    } catch (err) {
      console.log("User was not authorized", err.message);
      return {
        principalId: "user",
        policyDocument: {
          Version: "2012-10-17",
          Statement: [
            {
              Action: "execute-api:Invoke",
              Effect: "Deny",
              Resource: "*",
            },
          ],
        },
      };
    }
  }
);

function verifyToken(authHeader: string, secret: string): JwtToken {
  console.log("authHeader", authHeader);
  if (!authHeader) {
    throw new Error("No authorization header");
  }

  if (authHeader.toString().indexOf("bearer") > -1) {
    throw new Error("Invalid authorization header");
  }

  const splits = authHeader.split(" ");
  const token = splits[1];
  console.log("token", token);

  // use JWT to verify the token with the secret
  return verify(token, secret) as JwtToken;
  // A request has been authorized.
}

handler.use(
  secretsManager({
    cache: true,
    cacheExpiryInMills: 60000,
    throwOnFailedCall: true,
    secrets: {
      AUTH0_SECRET: secretId,
    },
  })
);

posted @ 2021-05-17 15:15 Zhentiw 阅读(138) 评论(0) 编辑收藏举报

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