How to extract fields from this AWS SecretsManager JSON Object?

Question

I am using AWS Secrets manager to protect the database credits of my REST API. I am using AWS Lambda, API Gateway and RDS (MySQL). Below is how I get them.

// Load the AWS SDK
var AWS = require('aws-sdk'),
    region = "us-east-1",
    secretName = "test-secret",
    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.
exports.handler = (event, context, callback) => {
    client.getSecretValue({
        SecretId: secretName
    }, function(err, data) {
        if (err) {
            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) {
                secret = data.SecretString;
            } else {
                let buff = new Buffer(data.SecretBinary, 'base64');
                decodedBinarySecret = buff.toString('ascii');
            }
        }
// Your code goes here. 
        console.log(secret);
    });
};

Below is the output

INFO    {"username":"***","password":"***","engine":"mysql","host":"***.***.us-east-1.rds.amazonaws.com","port":3306,"dbname":"***","dbInstanceIdentifier":"***"}

I tried to extract the password like below

let pass = secret.password;
        console.log(pass);

It gave the following

INFO    undefined

How can I extract fields such as password, username, databasename etc?

Answer 1

At first, you get back secret as data.SecretString, then now secret just is a normal string. In your case, it is a JSON string, you must cast your string to a JSON object, then you can access the information by attribute name easily.

To do that, you can use JSON.parse method to convert a json string to json object:

var secret = `{"username":"***","password":"***","engine":"mysql","host":"***.***.us-east-1.rds.amazonaws.com","port":3306,"dbname":"***","dbInstanceIdentifier":"***"}
`;

const secretObj = JSON.parse(secret);

console.log(secretObj.host)