Problem in JSR223 script JSR223 Sampler, while connecting to Azure Cosmos DB from Jmeter

I am trying to push my JMeter result to Azure Cosmos DB through the rest API exposed from the azure portal.

To achieve so I am using JSR223 sampler (as my pre processer) to get the auth token to connect to cosmos db also using the stand script to generate the auth_token (refer:https://github.com/MicrosoftCSA/documentdb-postman-collection/issues).

But I am getting Problem in JSR223 script JSR223 Sampler, message: javax.script.ScriptException: ReferenceError: "request" is not defined.

Code Snippet:

var mastKey = "master_key_for_cosmos_db";
log.info("mastKey = " + mastKey);

var today = new Date();
var UTCstring = today.toUTCString();
var url = "uri_key_for_cosmos_db"
var strippedurl = url.replace(new RegExp('^https?://[^/]+/'), '/');
log.info("stripped Url = " + strippedurl);

var strippedparts = strippedurl.split("/");
var truestrippedcount = (strippedparts.length - 1);
var resourceId = "";
var resType = "";
if (truestrippedcount % 2) {
    resType = strippedparts[truestrippedcount];
    if (truestrippedcount > 1) {
        var lastPart = strippedurl.lastIndexOf("/");
        resourceId = strippedurl.substring(1, lastPart);
    }
} else // its even (item request on resource)
{
    resType = strippedparts[truestrippedcount - 1];
    strippedurl = strippedurl.substring(1);
    resourceId = strippedurl;
}
var verb = request.method.toLowerCase();
var date = UTCstring.toLowerCase();
var key = CryptoJS.enc.Base64.parse(mastKey);
var text = (verb || "").toLowerCase() + "\n" +
    (resType || "").toLowerCase() + "\n" +
    (resourceId || "") + "\n" +
    (date || "").toLowerCase() + "\n" +
    "" + "\n";

var signature = CryptoJS.HmacSHA256(text, key);
var base64Bits = CryptoJS.enc.Base64.stringify(signature);
var MasterToken = "master";
var TokenVersion = "1.0";
auth = encodeURIComponent("type=" + MasterToken + "&ver=" + TokenVersion + "&sig=" + base64Bits);
vars.put("authToken", auth);

anything I am doing wrong or missed?