#Cognito User Pool

#Valid Triggers

Serverless supports all Cognito User Pool Triggers as specified here. Use this guide to understand the event objects that will be passed to your function.

#Simple event definition

This will create a Cognito User Pool with the specified name. You can reference the same pool multiple times.

functions:
  preSignUp:
    handler: preSignUp.handler
    events:
      - cognitoUserPool:
          pool: MyUserPool
          trigger: PreSignUp
  customMessage:
    handler: customMessage.handler
    events:
      - cognitoUserPool:
          pool: MyUserPool
          trigger: CustomMessage

#Multiple pools event definitions

This will create multiple Cognito User Pools with their specified names:

functions:
  preSignUpForPool1:
    handler: preSignUp.handler
    events:
      - cognitoUserPool:
          pool: MyUserPool1
          trigger: PreSignUp
  preSignUpForPool2:
    handler: preSignUp.handler
    events:
      - cognitoUserPool:
          pool: MyUserPool2
          trigger: PreSignUp

You can also deploy the same function for different user pools:

functions:
  preSignUp:
    handler: preSignUp.handler
    events:
      - cognitoUserPool:
          pool: MyUserPool1
          trigger: PreSignUp
      - cognitoUserPool:
          pool: MyUserPool2
          trigger: PreSignUp

#Custom message trigger handlers

For custom messages, you will need to check event.triggerSource type inside your handler function:

// customMessage.js
function handler(event, context, callback) {
  if (event.triggerSource === 'CustomMessage_AdminCreateUser') {
    // ...
  }
  if (event.triggerSource === 'CustomMessage_ResendCode') {
    // ...
  }
}

#Overriding a generated User Pool

A Cognito User Pool created by an event can be overridden by using the logical resource name in Resources:

functions:
  preSignUp:
    handler: preSignUpForPool1.handler
    events:
      - cognitoUserPool:
          pool: MyUserPool
          trigger: PreSignUp
  postConfirmation:
    handler: postConfirmation.handler
    events:
      - cognitoUserPool:
          pool: MyUserPool
          trigger: PostConfirmation

resources:
  Resources:
    CognitoUserPoolMyUserPool:
      Type: AWS::Cognito::UserPool