How to configure Serverless Cognito Lambda Triggers - amazon-web-services

Question

Using the Serverless framework to create a Cognito User Pool as well as several lambdas to be used for cognito events during TOPT SMS Authorization. Everything is created however the lambda functions are not registered with Cognito.
Relatively new to Serverless jut can't seem to get them to connect. Have tried pool names as others have tried to mark as already present at the end of creation the pool is there and the lambdas are there but there is no connection.
Currently following another post tried changing user pool to CognitoUserPoolMyUserPool and then in lambda referencing it as MyUserPool. Have also tried just CognitoUserPool in both locations and neither work.
Example serverless.yaml file:
service: cognito-authentication
frameworkVersion: ">=1.1.0 <2.0.0"
package:
individually: false
plugins:
- serverless-bundle
custom:
stage: ${opt:stage, self:provider.stage}
poolName: ${self:custom.stage}-user-pool
provider:
name: aws
runtime: nodejs10.x
stage: dev
iamRoleStatements:
- Effect: Allow
Action:
- sns:*
Resource:
- "*"
functions:
preSignUp:
handler: functions/pre-signup.main
events:
- cognitoUserPool:
pool: MyUserPool
trigger: PreSignUp
defineAuthChallenge:
handler: functions/define-auth-challenge.main
events:
- cognitoUserPool:
pool: MyUserPool
trigger: DefineAuthChallenge
createAuthChallenge:
handler: functions/create-auth-challenge.main
events:
- cognitoUserPool:
pool: MyUserPool
trigger: CreateAuthChallenge
verifyAuthChallengeResponse:
handler: functions/verify-auth-challenge-response.main
events:
- cognitoUserPool:
pool: MyUserPool
trigger: VerifyAuthChallengeResponse
resources:
Resources:
CognitoUserPoolMyUserPool:
Type: "AWS::Cognito::UserPool"
Properties:
# Generate a name based on the stage
UserPoolName: ${self:custom.poolName}
# Set phone_number as an alias
UsernameAttributes:
- phone_number
Policies:
PasswordPolicy:
MinimumLength: 6
RequireLowercase: False
RequireNumbers: False
RequireSymbols: False
RequireUppercase: False
CognitoUserPoolClient:
Type: "AWS::Cognito::UserPoolClient"
Properties:
# Generate an app client name based on the stage
ClientName: ${self:custom.stage}-sms-auth-client
UserPoolId:
Ref: CognitoUserPoolMyUserPool
ExplicitAuthFlows:
- CUSTOM_AUTH_FLOW_ONLY
GenerateSecret: false
Expectation is the User Pool is correctly created and configured to use the lambdas for triggered workflow execution.

Answer 1

I've copied pasted your code (and added relevant Lambda functions) and it works for me.
I've tested the PreSignUp with the following command:
aws cognito-idp admin-create-user --region <region> --user-pool-id <user-pool-id> --username <phone>
While not showing in the AWS Console Lambda UI, the triggers do show up in the Cognito->User Pools->dev-user-pool->Triggers, which is confusing.
Example repo: https://github.com/erezrokah/serverless-cognito-triggers

Answer 2

I found the issue in your serverless.yml. You are missing an indentation under cognitoUserPool. I tried it both ways and it works with the additional indentation.
preSignUp:
handler: functions/pre-signup.main
events:
- cognitoUserPool:
pool: MyUserPool
trigger: PreSignUp