Lambda(SAM)からAWS SQS(LocalStack) へメッセージ送信/受信を行う方法 メモ

• LocalStack上で動くAWS SQSのキューに対してAWS SAM CLIで動くLambdaからメッセージ送受信を行う方法をメモする。

構成

LocalStack準備

• docker-compose.yml

  version: "3.8"
  networks:
    container-link:
      name: docker.internal
  services:
    localstack:
      container_name: "${LOCALSTACK_DOCKER_NAME-localstack_main}"
      image: localstack/localstack
      ports:
        - "127.0.0.1:53:53"                # only required for Pro
        - "127.0.0.1:53:53/udp"            # only required for Pro
        - "127.0.0.1:443:443"              # only required for Pro
        - "127.0.0.1:4510-4530:4510-4530"  # only required for Pro
        - "127.0.0.1:4566:4566"
        - "127.0.0.1:4571:4571"
      environment:
        - SERVICES=${SERVICES- }
        - DEBUG=${DEBUG- }
        - DATA_DIR=${DATA_DIR- }
        - LAMBDA_EXECUTOR=${LAMBDA_EXECUTOR- }
        - LOCALSTACK_API_KEY=${LOCALSTACK_API_KEY- }  # only required for Pro
        - HOST_TMP_FOLDER=${TMPDIR:-/tmp/}localstack
        - DOCKER_HOST=unix:///var/run/docker.sock
      volumes:
        - "${TMPDIR:-/tmp}/localstack:/tmp/localstack"
        - "/var/run/docker.sock:/var/run/docker.sock"
      networks:
        - container-link

• 起動

  docker-compose up

SQS準備

キュー作成

aws sqs create-queue --queue-name test-queue --endpoint-url http://localhost:4566 --profile localstack 
{
    "QueueUrl": "http://localhost:4566/000000000000/test-queue"
}

キューの確認

aws sqs list-queues --endpoint-url http://localhost:4566 --profile localstack 
{
    "QueueUrls": [
        "http://localhost:4566/000000000000/test-queue"
    ]
}

Lambda準備

Lambda

• ひな形作成

  sam init

※ランタイムはPython3.8を選択。

• template.yml

  • Hello World Exampleを利用する。
  • POST(メッセージ送信)/GET(メッセージ受信)用に以下修正

  Events:
          SendMessage:
            Type: Api # More info about API Event Source: https://github.com/awslabs/serverless-application-model/blob/master/versions/2016-10-31.md#api
            Properties:
              Path: /message
              Method: post
          ReceiveMessage:
            Type: Api # More info about API Event Source: https://github.com/awslabs/serverless-application-model/blob/master/versions/2016-10-31.md#api
            Properties:
              Path: /message
              Method: get
  

• requrements.txt

  requests
  boto3

※SQSアクセス用にboto3追加

• Lambda処理(app.py)修正

  import json
  from boto3.session import Session
  from datetime import datetime

  # SQS 接続設定
  session = Session(
      aws_access_key_id='dummy',
      aws_secret_access_key='dummy',
      region_name='ap-northeast-1'
  )
  client = session.client(
      service_name='sqs', 
      endpoint_url='http://localstack:4566'
  )


  def lambda_handler(event, context):
      # キューURL
      queue_url="http://localstack:4566/000000000000/test-queue"
      if event["httpMethod"] == "POST":
          # メッセージ送信
          response = client.send_message(QueueUrl=queue_url, MessageBody=json.dumps(event["body"]))
          res = {"MD5OfMessageBody":response["MD5OfMessageBody"],"MessageId":response["MessageId"]}
          return {
              "statusCode": 200,
              "body": json.dumps(res),
          }
      if event["httpMethod"] == "GET":
          # メッセージ受信
          response = client.receive_message(QueueUrl=queue_url, MaxNumberOfMessages=1, VisibilityTimeout=60)
          # メッセージ削除
          for message in response["Messages"]:
              client.delete_message(QueueUrl=queue_url, ReceiptHandle=message["ReceiptHandle"])

          return {
              "statusCode": 200,
              "body": json.dumps(response["Messages"][0]),
          }

動作確認

• ビルド

  sam build

• 実行

  sam local start-api --docker-network docker.internal

• メッセージ送信

  • リクエスト

  POST /message HTTP/1.1
  Host: localhost:3000
  Content-Type: application/json
  Content-Length: 34
  
  {
      "message":"test message1"
  }
  

  • レスポンス

  {
      "MD5OfMessageBody": "65b7b348e7f42918ad0d487de1a20c47", 
      "MessageId": "2cafdcd9-2620-14b4-645a-da15dbddf8b5"
  }
  

• メッセージ受信

  • リクエスト

  GET /message HTTP/1.1
  Host: localhost:3000
  Content-Type: application/json
  

  • レスポンス

  {
      "MessageId": "2cafdcd9-2620-14b4-645a-da15dbddf8b5", 
      "ReceiptHandle": "imvqeantfgqrgtkzhwowwzywsxmtdrakkhjdqkwyybxlevsltiefnfjrmoksniovizimonlkixhdixufzqlmejbmtwcxvwuaintwwojbompbfqjhsmokjtojxdlnxquvqslbrevmrinvzxeymkrcpstcmzrtfzhlclwpmkcuokfqjdahkiqhlxcli", 
      "MD5OfBody": "65b7b348e7f42918ad0d487de1a20c47", 
      "Body": "\"{\\n    \\\"message\\\":\\\"test message1\\\"\\n}\""
  }
  

参考情報

• AWS SQSのメッセージをPythonで送受信する