How can i create a lambda function which is not connected to REST endpoint using SST? I want this function to be called after cognito signup. Using SST default project structure, i created a file called

PostSignup.js

and placed it in

src/

... when i did

npc sst start

, i assumed that this funciton will be created but got the message "no changes". How can i i use SST to do so?

Hey @Muhammad Ali, it seems you are trying to setup PostSignup trigger for Cognito User Pool. Can you confirm that?

Yeah, I need to create PostSignup and PostAuth lambdas. PostSignup i need to persist "extra fields" which would be added as part of signup. And PostAuth is needed to insert some extra meta data for accessing specific details. I haven't setup anything yet but want to do it using Incognito. Would prefer if everything can be done via sst so that i don't have to replicate to other regions but given that cognito is global, i don't mind using ui to setup cognito

I see. This might help https://docs.serverless-stack.com/constructs/Auth#configuring-user-pool-triggers

This is super helpful. thanks. one more question. how would i tell which cognito pool to use? also, am i suppose to create cognito pool using ui?

Hey @Muhammad Ali, if you don’t already have a user pool, it’s always good to create one in code rather than the UI.

Follow up questions 1. I am using cognito postConfirmation trigger. In the trigger, i am persisting some data to dynamodb. Question is what should i do once i persist data. I tried

return {statusCode: 200}

and got error that unrecognized lambda output error. 2. How can i store utc datetime in iso format in dynamodb. I used this

createdAt: new Date().toISOString,

and got an empty value in dynamodb.

1 you need to return the event that was passed to the function. 2 toISOString is a function