serverless.yml example

serverless.yml

# Welcome to Serverless!
#
# This file is the main config file for your service.
# It's very minimal at this point and uses default values.
# You can always add more config options for more control.
# We've included some commented out config examples here.
# Just uncomment any of them to get that config option.
#
# For full config options, check the docs:
#    docs.serverless.com
#
# Happy Coding!

service: example-service
# app and org for use with dashboard.serverless.com
#app: your-app-name
#org: your-org-name

# You can pin your service to only deploy with a specific Serverless version
# Check out our docs for more details
frameworkVersion: '2'
useDotenv: true
variablesResolutionMode: 20210326

provider:
  name: aws
  runtime: nodejs12.x
  lambdaHashingVersion: 20201221
  stage: ${opt:stage, 'dev'}
  region: ${opt:region, 'ap-northeast-1'}
  environment:
    SLACK_BOT_USERNAME: ${env:SLACK_BOT_USERNAME, 'bot'}
    SLACK_BOT_TOKEN: ${env:SLACK_BOT_TOKEN}
    SLACK_CHANNEL: ${env:SLACK_CHANNEL}

# you can add statements to the Lambda function's IAM Role here
#  iamRoleStatements:
#    - Effect: "Allow"
#      Action:
#        - "s3:ListBucket"
#      Resource: { "Fn::Join" : ["", ["arn:aws:s3:::", { "Ref" : "ServerlessDeploymentBucket" } ] ]  }
#    - Effect: "Allow"
#      Action:
#        - "s3:PutObject"
#      Resource:
#        Fn::Join:
#          - ""
#          - - "arn:aws:s3:::"
#            - "Ref" : "ServerlessDeploymentBucket"
#            - "/*"

# you can add packaging information here
# package:
#   patterns:
#     - '!exclude-me.js'
#     - '!exclude-me-dir/**'
#     - include-me.js
#     - include-me-dir/**

custom:
  SubscriberLambdaFunctionName: ${self:service}-${self:provider.stage}-notify

functions:
  notify:
    handler: dist/index.handler
    name: ${self:custom.SubscriberLambdaFunctionName}
    events:
    - httpApi:
        path: '/webhook'
        method: 'POST'
#    The following are a few example events you can configure
#    NOTE: Please make sure to change your handler code to work with those events
#    Check the event documentation for details
#    events:
#      - httpApi:
#          path: /users/create
#          method: get
#      - websocket: $connect
#      - s3: ${env:BUCKET}
#      - schedule: rate(10 minutes)
#      - sns: greeter-topic
#      - stream: arn:aws:dynamodb:region:XXXXXX:table/foo/stream/1970-01-01T00:00:00.000
#      - alexaSkill: amzn1.ask.skill.xx-xx-xx-xx
#      - alexaSmartHome: amzn1.ask.skill.xx-xx-xx-xx
#      - iot:
#          sql: "SELECT * FROM 'some_topic'"
#      - cloudwatchEvent:
#          event:
#            source:
#              - "aws.ec2"
#            detail-type:
#              - "EC2 Instance State-change Notification"
#            detail:
#              state:
#                - pending
#      - cloudwatchLog: '/aws/lambda/hello'
#      - cognitoUserPool:
#          pool: MyUserPool
#          trigger: PreSignUp
#      - alb:
#          listenerArn: arn:aws:elasticloadbalancing:us-east-1:XXXXXX:listener/app/my-load-balancer/50dc6c495c0c9188/
#          priority: 1
#          conditions:
#            host: example.com
#            path: /hello

#    Define function environment variables here
#    environment:
#      variable2: value2

# you can add CloudFormation resource templates here
resources:
  Resources:
    ApplicationDeploymentLogGroup:
      Type: AWS::Logs::LogGroup
      Properties: 
        LogGroupName: ${self:service}-${self:provider.stage}-deployment-log-group
        RetentionInDays: 30
    ApplicationDeploymentLogSubscription:
      Type: AWS::Logs::SubscriptionFilter
      Properties:
        DestinationArn:
          arn:aws:lambda:${aws:region}:${aws:accountId}:function:${self:custom.SubscriberLambdaFunctionName}
        FilterPattern: "ERROR"
        LogGroupName: !Ref ApplicationDeploymentLogGroup
    SubscriptionPermission:
      Type: AWS::Lambda::Permission
      Properties:
        Action: "lambda:InvokeFunction"
        FunctionName: arn:aws:lambda:${aws:region}:${aws:accountId}:function:${self:custom.SubscriberLambdaFunctionName}
        Principal: logs.${aws:region}.amazonaws.com
  Outputs:
    LogGroupName:
      Description: "LogGroup name"
      Value: !Ref ApplicationDeploymentLogGroup
    LogGroupArn:
      Description: "LogGroup ARN"
      Value: !GetAtt ApplicationDeploymentLogGroup.Arn

README

Serverless Framework のテンプレートに関する、「知っておくと捗る」ちょっとした書き方を紹介する

発表: AWS Dev Day 2021 Lambda だけじゃもったいない。サーバーレス開発の第二歩目を踏み出そう

このテンプレートで作ろうとしている題材について

HTTP API と CloudWatch Logs (subscription filter) からメッセージを受け取り、Slack などの外部システムに通知する Lambda ハンドラの作成、を意図している。

resource	desccription
ApplicationDeploymentLogGroup	subscribe 対象のロググループ
notify (funcion)	ログを受け取って処理する Lambda ハンドラ

環境変数

2021/09/28 時点の最新版の Serverless Framework では、標準機能で dotenv の読み込みに対応している

https://gist.github.com/hassaku63/3447a4381e8001367093ddc61c5ae13f#file-serverless-yml-L31-L34

のような ${env:ENV_VAR} のような記法での参照が可能。

参考: https://www.serverless.com/framework/docs/deprecations/#LOAD_VARIABLES_FROM_ENV_FILES

CloudFormation 疑似パラメータ

2021/09/28 時点の最新版の Serverless Framework では、CloudFormation の疑似パラメータを ${aws:XXX} の記法で参照可能。

CloudFormation 疑似パラメータ参照: https://docs.aws.amazon.com/ja_jp/AWSCloudFormation/latest/UserGuide/pseudo-parameter-reference.html

このスニペットでは、

https://gist.github.com/hassaku63/3447a4381e8001367093ddc61c5ae13f#file-serverless-yml-L119-L125

の ${aws:region} や ${aws:accountId} が該当する。

${aws:XXX} の変数を使用するためには、yml のトップ階層に variablesResolutionMode を指定する必要がある。

variablesResolutionMode: 20210326