how do I use aws secret manager with nodejs lambda

Question

I tried to wrap the example code snippet to get secrets in a function and then call it but it does not appear to be working. I suspect I am calling it asynchronously and I need to call it synchronously? I just want a function I can call to get a secret value and put it in a var.

this is the function:

//outside exports.handler = (event, context, callback) => { function getSecret(secretName) {   // Load the AWS SDK   var AWS = require('aws-sdk'),       region = process.env.AWS_REGION,       secretName = secretName,       secret,       decodedBinarySecret;    // Create a Secrets Manager client   var client = new AWS.SecretsManager({       region: region   });    // 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.    client.getSecretValue({SecretId: secretName}, function(err, data) {       if (err) {           if (err.code === 'DecryptionFailureException')               // Secrets Manager can't decrypt the protected secret text using the provided KMS key.               // Deal with the exception here, and/or rethrow at your discretion.               throw err;           else if (err.code === 'InternalServiceErrorException')               // An error occurred on the server side.               // Deal with the exception here, and/or rethrow at your discretion.               throw err;           else if (err.code === 'InvalidParameterException')               // You provided an invalid value for a parameter.               // Deal with the exception here, and/or rethrow at your discretion.               throw err;           else if (err.code === 'InvalidRequestException')               // You provided a parameter value that is not valid for the current state of the resource.               // Deal with the exception here, and/or rethrow at your discretion.               throw err;           else if (err.code === 'ResourceNotFoundException')               // We can't find the resource that you asked for.               // Deal with the exception here, and/or rethrow at your discretion.               throw 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) {               return data.SecretString;           } else {               let buff = new Buffer(data.SecretBinary, 'base64');               return buff.toString('ascii');           }     }   }); } 

Then I call it

// inside exports.handler = (event, context, callback) => { var secret = getSecret('mySecret') console.log('mysecret: ' + secret ) 

The secret var is always undefined

EDIT: Async only works with promises so I had to make my function async and return a promise:

async function mySecrets(secretName) {     // Load the AWS SDK     var AWS = require('aws-sdk'),         region = process.env.AWS_REGION,         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) {                     resolve(data.SecretString);                 } else {                     let buff = new Buffer(data.SecretBinary, 'base64');                     resolve(buff.toString('ascii'));                 }             }         });     }); }  ..... // inside handler exports.handler = async (event) => { .... var value = await mySecrets('mysecret') 

Answer 1

You need wait for the async call to finish.

Inside your main handler you will have something like:

// inside your main handler exports.handler =  async function(event, context) {     var secret = await getSecret('mySecret')     console.log('mysecret: ' + secret )      return ...     }