Locally run Lambda would not log all outputs - node.js

Question

I have the following Lambda.
const AWS = require('aws-sdk');
exports.lambdaHandler = async (event, context) => {
console.log("START v5");
const SNSarn = process.env.SNS;
console.log(SNSarn);
const snsParams={
Message: "test",
TopicArn: SNSarn
};
const SNS = new AWS.SNS();
SNS.publish(snsParams, function(err,data){
console.log ("We are in the callback!");
if (err) {
console.log('Error sending a message', err);
context.done(err,'We have errors');
}
console.log('Sent message');
context.done(null,"Done!");
});
console.log('END');
};
When I run it locally, ther lambda performs as expected and pushes a message to SNS.
For some reason, I do not see the console.log that is in the callback.
How do I fix it so I can also see logs from callbacks?
Below is the output I do see:
START RequestId: ff2691cc-a7d0-40f2-a956-277bxxxx21d Version: $LATEST
2021-11-15T21:17:17.968Z ff2691cc-a7d0-40f2-a956-277bxxxx821d INFO START v5
2021-11-15T21:17:17.970Z ff2691cc-a7d0-40f2-a956-277bxxxx821d INFO arn:aws:sns:us-east-1:xxxxxxxxxxxxxxx:tooktook-topic
2021-11-15T21:17:17.992Z ff2691cc-a7d0-40f2-a956-277bxxxx821d INFO END
END RequestId: ff2691cc-a7d0-40f2-a956-277bxxxx821d
REPORT RequestId: ff2691cc-a7d0-40f2-a956-277bxxxx821d Init Duration: 0.19 ms Duration: 261.33 ms Billed Duration: 300 ms Memory Size: 128 MB Max Memory Used: 128 MB

Answer 1

In method SNS.publish, you are using callback which is asynchronous in nature and there is a possibility of successful lambda execution before callback is even called. SNS takes a bit of time for execution. you need to use async/ await in this case. AWS APIs support promises.
Here is an example:
const AWS = require('aws-sdk');
exports.lambdaHandler = async (event, context) => {
console.log("START v5");
const SNSarn = process.env.SNS;
console.log(SNSarn);
const snsParams={
Message: "test",
TopicArn: SNSarn
};
const SNS = new AWS.SNS();
try {
const data = await SNS.publish(snsParams).toPromise();
console.log('Sent Message');
context.done(null, 'Done');
} catch (error) {
console.log('We are in the callback!');
context.done(err, 'We have errors');
}
console.log('END');
};