nifi scripted processor example

flowFile = session.get();

function getRandomInt(min, max) {
  min = Math.ceil(min);
  max = Math.floor(max);
  return Math.floor(Math.random() * (max - min)) + min; //The maximum is exclusive and the minimum is inclusive
}

if (flowFile != null) {

    var StreamCallback = Java.type("org.apache.nifi.processor.io.StreamCallback");
    var IOUtils = Java.type("org.apache.commons.io.IOUtils");
    var StandardCharsets = Java.type("java.nio.charset.StandardCharsets");
    var transformed_message = {};
    var error = false;
    var line = influxdbmeasurement.evaluateAttributeExpressions().getValue();



    // Get attributes
    flowFile = session.write(flowFile, new StreamCallback(function (inputStream, outputStream) {
        // Read input FlowFile content
        var content = IOUtils.toString(inputStream, StandardCharsets.UTF_8); // message or content

        try {

            line = line + ",providerId=" + providerid.evaluateAttributeExpressions().getValue() +
                ",type=" + type.evaluateAttributeExpressions().getValue() +
                " value=" + "1"
                + " " + (Date.now() * 1000000 + getRandomInt(0,1000));

            // Write output content
            if (transformed_message) {
                outputStream.write(line.getBytes(StandardCharsets.UTF_8));
            }
        } catch (e) {
            error = true;
            outputStream.write(content.getBytes(StandardCharsets.UTF_8));
        }
    }));

    if (error) {
        session.transfer(flowFile, REL_FAILURE)
    } else {
        session.transfer(flowFile, REL_SUCCESS)
    }
}