indexParam value is not dynamically replaced in body after concurrency's number of requests

[ashishnetworks]

I was doing one of the performance tests for my current project and I realized that indexParam is not dynamically replaced in the body after the initial concurrency number of requests. Look at the following code of loadTestScript.js

var loadtest = require('loadtest')

function statusCallback (error, result, latency) {
  console.log('Request index: %j, totalError %j, errorcode frequency %j error %j and RPS %j', result ? result.requestIndex : 'NOT FOUND', latency.totalErrors, latency.errorCodes, error, latency.rps)
}

let counter = 0
function optionsObject() {
    return {
        url: 'http://localhost:3000?name=value',
        maxRequests: 10 ,
        concurrency: 3,
        method: 'POST',
        contentType: 'application/json',
        headers: {
            'Content-Type': 'application/json'
        },
        indexParam: "value",
        body:   {
            id: "value"
        },
    statusCallback: statusCallback,
    indexParamCallback: function () {
        return ++counter
    }}
}

loadtest.loadTest(optionsObject(), function (error, result) {
    // This blocks gets called when whole test is finished
  if (error) {
    console.log('Got an error: %s', error)
  }
  console.log('Got the following result from the test>>\n', result)
})

To check if values are dynamically received in the server, I ran a local express server on localhost:3000 with the following code

let reqCount = 0
app.post('/', function (req, res) {
    console.log('------------------------------------')
    console.log(`Received req for count ${++reqCount}`)
    console.log(`Query params: `, req.query)
    console.log(`Req body: `, req.body)
    res.send('hello world')
})

and then I ran the loadTestScript.js script with the node loadTestScript.js command and the following is the output that I got

If you look at the request numbers 1, 2 and 3 everything looks good. But from request count 4 you will notice the value received in the body is static (last value of the request) while the name's value received through the query parameter is still dynamic. FYI if I increase the concurrency to 5 then the body will be dynamic till the 5th requests but later that it will stick to a static value. I believe the purpose of indexParam in the body is to provide dynamic values in the body irrespective of a number of concurrencies, currently, it's not serving that purpose.

cc: @alexfernandez

[alexfernandez]

Excellent bug report! :+1: Care to debug it and send a pull request? :wink:

[alexfernandez]

Sorry for the long delay. Should work now, please review.