[PYTHON] [AWS] I made a reminder BOT with LINE WORKS

It's the 7th day of Advent Calendar.

This time, I created a reminder BOT in the AWS environment. Cloudformation templates will also be posted, so please have a look if you are interested.

Click here for an article on implementation in Lambda (https://qiita.com/peyryo/items/ff5a2a693d47ce13fa18)

Completed BOT

The exchange of BOT is like this.

It has the following functions.

--Event registration function --You can register the event you want to remind by entering the event title and time. --Registration will start by pressing the "Event Registration" button.

--Event reference function --You can refer to the registered event. --You can refer to the event by clicking the "Browse for event" button.

--Event notification function --BOT will notify you when the date and time of the registered event is approaching.

This time, I placed a button on the BOT using a fixed talk menu.

overall structure

AWS was used to build the BOT backend. This time, I tried to build it without a server in order to make it as easy as possible.

API Gateway and Lambda are responsible for interacting with the BOT, and DynamoDB is used for talk state management.

Messages to LINEWORKS-> AWS are processed by lambda via API Gateway. Therefore, the URL of API Gateway is set in the callback URL of BOT of LINE WORKS.

Message notification to AWS-> LINEWORKS is done by Lambda for sending via SQS. The access token and authentication key required to send a message are managed by S3.

Remind notifications take advantage of CloudWatch Events to launch Lambda on a regular basis. This is achieved by polling the events in DynamoDB.

template

Cloudformation is used to create AWS resources. This time, I used AWS SAM, which is easy to write because I am using Lambda and API Gateway.

The names and setting values of various resources are set appropriately, so if you want to use them, change them accordingly.

template.yaml

AWSTemplateFormatVersion: 2010-09-09
Transform:
- AWS::Serverless-2016-10-31

#Set template parameters to pass the required credentials to the LINEWORKS BOT
Parameters:
  BotNo:
    Description: LINEWORKS bot number
    Type: String
  ApiId:
    Description: LINEWORKS api id
    Type: String
  ServerListId:
    Description: LINEWORKS server list id
    Type: String
  ServerApiConsumerKey:
    Description: LINEWORKS server api consumer key
    Type: String

#Properties that apply to all Lambda functions
Globals:
  Function:
    AutoPublishAlias: live
    Timeout: 10
    #Properties applied to Lambda functions
    Environment:
      Variables:
        BOT_NO: !Ref BotNo
        API_ID: !Ref ApiId
        SERVER_LIST_ID: !Ref ServerListId 
        SERVER_API_CONSUMER_KEY: !Ref ServerApiConsumerKey

Resources:

  # AWS ->Lambda function responsible for notifying LINE WORKS
  SendLambda:
    Type: AWS::Serverless::Function
    Properties:
      FunctionName: 'send-lineworks-message'
      Handler: index.handler
      Runtime: python3.7
      CodeUri: lambda/send-message
      Role:
        Fn::GetAtt:
        - LambdaExecutionRole
        - Arn
      Events:
        #Define SQS triggers here
        SQS1:
          Type: SQS
          Properties:
            Queue:
              Fn::GetAtt:
                - MessageQueue
                - Arn
            BatchSize: 10

  # LINEWORKS ->Lambda function responsible for AWS reception processing
  RecieveMessage:
    Type: AWS::Serverless::Function
    Properties:
      FunctionName: 'recieve-lineworks-message'
      Handler: index.handler
      Runtime: python3.7
      CodeUri: lambda/recieve-message
      Role:
        Fn::GetAtt:
        - LambdaExecutionRole
        - Arn
      Events:
        PostEvent:
          Type: Api
          Properties:
            Path: /callback
            Method: post

  #Lambda function to get the event registered from DynamoDB
  GetEvents:
    Type: AWS::Serverless::Function
    Properties:
      FunctionName: 'get-events'
      Handler: index.handler
      Runtime: python3.7
      CodeUri: lambda/get-events
      Role:
        Fn::GetAtt:
        - LambdaExecutionRole
        - Arn
      Events:
        #Define CloudWatch Event here
        Schedule:
          Type: Schedule
          Properties:
            #Polling interval is 5 minutes
            Schedule: rate(5 minutes)

  #Lambda function permissions (sweet)
  #For now, apply to all Lambda functions
  LambdaExecutionRole:
    Description: Creating service role in IAM for AWS Lambda
    Type: AWS::IAM::Role
    Properties:
      RoleName: !Sub 'LineWorksLambdaExecution'
      AssumeRolePolicyDocument:
        Statement:
        - Effect: Allow
          Principal:
            Service: [lambda.amazonaws.com]
          Action: sts:AssumeRole
      Path: /
      ManagedPolicyArns:
        - !Sub 'arn:${AWS::Partition}:iam::aws:policy/service-role/AWSLambdaBasicExecutionRole'
      Policies:
        - 
         PolicyName: lineworks-lambda-execution-role
         PolicyDocument:
           Version: "2012-10-17"
           Statement:
              - 
                Effect: "Allow"
                Action: "sqs:*"
                Resource: "*"
              - 
                Effect: "Allow"
                Action: "dynamodb:*"
                Resource: "*"

  #DynamoDB definition
  LineWorksDB:
    Type: AWS::DynamoDB::Table
    Properties:
      AttributeDefinitions: 
        - 
          AttributeName: "Hash"
          AttributeType: "S"
        - 
          AttributeName: "Range"
          AttributeType: "S"
      KeySchema: 
        - 
          AttributeName: "Hash"
          KeyType: "HASH"
        - 
          AttributeName: "Range"
          KeyType: "RANGE"
      ProvisionedThroughput:
        ReadCapacityUnits: "1"
        WriteCapacityUnits: "1"
      TableName: lineworks-sample-table
      #Set "Expire Time" to TTL
      #Items can be deleted automatically by setting TTL
      TimeToLiveSpecification:
        AttributeName: ExpireTime
        Enabled: true
      Tags:
        - Key: key
          Value: value

  #Definition of SQS
  MessageQueue:
    Type: 'AWS::SQS::Queue'
    Properties:
      QueueName: lineworks-message-queue

When deploying, I used the following script. The stack name is also appropriate.

build.sh

###Change here according to each environment
BOT_NO="xxx"
API_ID="yyy"
SERVER_LIST_ID="zzz"
SERVER_API_CONSUMER_KEY="aaa"
DEPLOY_S3_BUCKET = "bbb"
###

aws cloudformation package --template template.yml --s3-bucket ${DEPLOY_S3_BUCKET} --output-template template-export.yml

aws cloudformation deploy \
    --template-file template-export.yml \
    --stack-name lineworks-sample-stack \
    --capabilities CAPABILITY_NAMED_IAM \
    --parameter-overrides BotNo=${BOT_NO} ApiId=${API_ID} ServerListId=${SERVER_LIST_ID} ServerApiConsumerKey=${SERVER_API_CONSUMER_KEY}

Summary

I tried to create a reminder BOT in a serverless environment on AWS.

Next time, I'd like to introduce you to the implementation of Lambda functions. Implementation link