How to generate AWS signature from JMeter? - amazon-web-services

Question

Here is my code in the JSR223 PreProcessor.
import javax.crypto.Mac
import javax.crypto.spec.SecretKeySpec
import java.security.InvalidKeyException
import java.security.MessageDigest
import groovy.json.JsonSlurper
import java.text.SimpleDateFormat
static byte[] HmacSHA256(String data, byte[] key) throws Exception {
String algorithm="HmacSHA256";
Mac mac = Mac.getInstance(algorithm);
mac.init(new SecretKeySpec(key, algorithm));
return mac.doFinal(data.getBytes("UTF8"));
}
static byte[] getSignatureKey(String key, String dateStamp, String regionName, String serviceName) throws Exception {
byte[] kSecret = ("AWS4" + key).getBytes("UTF8");
byte[] kDate = HmacSHA256(dateStamp, kSecret);
byte[] kRegion = HmacSHA256(regionName, kDate);
byte[] kService = HmacSHA256(serviceName, kRegion);
byte[] kSigning = HmacSHA256("aws4_request", kService);
return kSigning;
}
Example parameter values to the function getSignatureKey are (these I am passing to the Parameters section of the JSR223 PreProcessor as variables)
key = eC6hEyRSTXMzsG6+juOObz8LbXb36iEYW7PPN1MJ
dateStamp = 20190123T083434Z
regionName = us-west-2
serviceName = test-mlp-us-west-2-4023179c-7708-4c5e-a831-28259b8a8872.s3.us-west-2.amazonaws.com
This code is not working and not generating the AWS signature.
Here is the sample Signature value I need to get
Signature=2a6092ec4ff49dc9j3b92d436635a57f312753kcc9f553ce1718b9b1594c4362
1.What is wrong with this code?
2.How can I assign the AWS signature to a variable and use in the JMeter?

Answer 1

If "This code is not working" the first thing you should do is to look into jmeter.log file - in case of Groovy script failure it will contain information regarding what exactly failed and why and some hints to fix.
I also think you should generate the signature basing on request details (URL, parameters, headers, etc.)
StringToSign =
Algorithm + \n +
RequestDateTime + \n +
CredentialScope + \n +
HashedCanonicalRequest
See Create a String to Sign for Signature Version 4
The whole process with examples is described in the How to Handle Dynamic AWS SigV4 in JMeter for API Testing and the test plan you can use as the reference is available in the GitHub repo.