[AWS][Amplify] Invoke function locally crashs with no error

Question

I have just joined a developpment team, and the project should run in the cloud using amplify. I have a function called usershandler that i want to run locally. For that, i used : amplify invoke function usershandler This is the output i get :

Starting execution...
EVENT: {"httpMethod":"GET","body":"{\"name\": \"Amplify\"}","path":"/users","resource":"/{proxy+}","queryStringParameters":{}}
App started
get All VSM called

Connection to database was a success
null
Result:
{"statusCode":200,"body":"{\"success\":true,\"results\":[]}","headers":{"x-powered-by":"Express","access-control-allow-origin":"*","access-control-allow-headers":"Origin, X-Requested-With, Content-Type, Accept","content-type":"application/json; charset=utf-8","content-length":"29","etag":"W/\"1d-4wD7ChrrlHssGyekznKfKxR7ImE\"","date":"Tue, 21 Jul 2020 12:32:36 GMT","connection":"close"},"isBase64Encoded":false}
Finished execution.

EDIT : Also, when running the invoke command, amplify asks me for a src/event.json while i've seen it looking for the index.js for some ??

EDIT 2 [SOLVED] : downgrading @aws-amplify/cli to 4.14.1 seems to solve this :)

Expected behavior : The server should continue running so i can use it .. Actual behavior : It always stops after the finished execution message.

The connection to the db works fine, the config.json contains correct values. Don't know why it is acting like this. Have anybody had the same problem? Have a nice day.

Answer 1

Short answer: You are running the invoke command which is doing just what it is supposed to be doing - invoking the lambda function.

If you are looking to get a local API up, then run the following command:

sam local start-api

This will read your template and based on the endpoints you have setup, run them locally essentially mocking API Gateway locally. Read more about it in the official docs here.

Explanation:

This command comes is one of offering of AWS Serverless Application Model (AWS SAM). A tool to develop serverless application. It is essentially an abstraction of AWS Cloufdformation. Similarly Amplify is an abstraction that makes it simple to not only develop and manage the backend but also brings that power to frontend. As both of them essentially use Cloudformation templates underneeth, you can leverage the capabilities of one tool with another.
SAM provides a robust set of tools for local development invcluding running a local lambda mocking server, in case you are not using API Gateway.

I use this combination to develop and test my frontend along with backend which is in golang, a language which is not as mature as javascript as a backend language with Amplify as of now.