AWS Lambda Function Appears to Hang

Question

This is most likely a misunderstanding on my part but here it goes. I have a lambda function. The only thing it is doing at the moment is retrieving a secret from secrets manager. If I run it in an async function in my debugger (cloud9 in this case) it works. Once I put it in the handler and upload the function to lambda and then test it, it times out. Currently the time out on the function is set to 1 minute 30 seconds. That should be way over what it needs as it returns almost instantly in Cloud9. I don't see anything in CloudWatch that would be helpful. I feel like either my approach is incorrect or I'm missing something obvious or just misunderstanding something fundamental.

Example Function

    async function GetSecrets(secretName) {
    // Load the AWS SDK
    var AWS = require('aws-sdk'),
        region = "Region Secret is in",
        secretName = secretName,
        secret,
        decodedBinarySecret;

    // Create a Secrets Manager client
    var client = new AWS.SecretsManager({
        region: region
    });

    return new Promise((resolve,reject)=>{
        client.getSecretValue({SecretId: secretName}, function(err, data) {
            // In this sample we only handle the specific exceptions for the 'GetSecretValue' API.
            // See https://docs.aws.amazon.com/secretsmanager/latest/apireference/API_GetSecretValue.html
            // We rethrow the exception by default.
            if (err) {
                reject(err);
            }
            else {
                // Decrypts secret using the associated KMS CMK.
                // Depending on whether the secret is a string or binary, one of these fields will be populated.
                if ('SecretString' in data) {
                    console.log("I got here and here is the data: " + data)
                    resolve(data.SecretString);
                } else {
                    let buff = new Buffer(data.SecretBinary, 'base64');
                    resolve(buff.toString('ascii'));
                }
            }
        });
    });
}
// This Works in Cloud9 
/*(async myFunc =>{
     var value = await GetSecrets('SecretName')
     console.log(value)
})();
*/

// inside handler - this times out in lambda
exports.handler =  async function(event, context) {
    var value = await GetSecrets('SecretName')
    const response = {
    statusCode: 200,
    body: JSON.stringify({ message: 'hello world' })
  }
  return response
}

Did you ever find a solution? I have the same problem. I cannot call any other AWS services through the sdk without it hanging. I have given my Lambda full access to everything it needs. I have even tested a python script with the equivalent SDK calls and SAME execution role, which WORKS! I have tested on .net core 3 and 2, hangs on both. — slaw, Oct 07 '21 at 11:08

Divanshu Aggarwal · Answer 1 · 2021-03-03T17:50:34.200

You are not calling callback function. try

    exports.handler = (event, context, callback) =>{
    var value = await GetSecrets('SecretName')
    const response = {
    statusCode: 200,
    body: JSON.stringify({ message: 'hello world' })
    }
    callback(null, 'success');
    }

callback function is used to return success or failure.This needs to be passed for lambda function to be completed. If you want to return response to lambda use response instead of 'success'

AWS Lambda Function Appears to Hang

1 Answers1