serverless.yml

# NOTE: update this with your service name
service: serverless-lambda-sns-example

plugins:
  - serverless-webpack
  - serverless-offline
  - serverless-offline-sns

# serverless-webpack configuration
# Enable auto-packing of external modules
custom:
  webpack:
    includeModules:
      forceExclude:
        - aws-sdk
  serverless-offline-sns:
    port: 4002 # a free port for the sns server to run on
    debug: true
  mySnsTopic: "${self:service}-${self:provider.stage}-sns-consume"
  mySnsTopicArn:
    local:
      "arn:aws:sns:us-east-1:123456789012:${self:custom.mySnsTopic}"
    dev:
      { "Fn::Join" : ["", ["arn:aws:sns:${self:provider.region}:", { "Ref" : "AWS::AccountId" }, ":${self:custom.mySnsTopic}" ] ]  }
    prod:
     { "Fn::Join" : ["", ["arn:aws:sns:${self:provider.region}:", { "Ref" : "AWS::AccountId" }, ":${self:custom.mySnsTopic}" ] ]  }

provider:
  name: aws
  runtime: nodejs8.10
  stage: ${opt:stage,'dev'}
  region: ${opt:region, 'us-east-1'}  
  environment: ${file(env.yml):${self:provider.stage}}
  iamRoleStatements:
    - Effect: Allow
      Action:
        - SNS:Publish
      Resource: { "Fn::Join" : ["", ["arn:aws:sns:${self:provider.region}:", { "Ref" : "AWS::AccountId" }, ":${self:custom.mySnsTopic}" ] ]  }

functions:
  snsConsume:
    handler: functions/snsConsume.handler
    events:
      - sns: ${self:custom.mySnsTopic}
  snsPublish:
    handler: functions/snsPublish.handler
    events:
      - http:
          path: snsPublish
          method: post
          cors: true
    environment:
      mySnsTopicArn: ${self:custom.mySnsTopicArn.${self:provider.stage}}