Add Reporting to the Consumer Groovy Script

[julianharty]

The current groovy script kafka-consumer-timestamp.groovy doesn't report progress or results to jmeter. We'd like to enhance the script so we can take advantage of jmeter's reporting and analysis capabilities. Also jmeter will then also communicate progress to the console which helps whoever's running the tests know 'something' is happening.

The essential data include:

• latency (the time delay between when the producer wrote the message and we received it)
• detected problems e.g. out-of-order or missing messages
• throughput (how many messages this thread is processing)

[ISNIT0]

Samplers can only return 1 SampleResult. Because we create one consumer to receive many messages.

We need to find some way of recording many SampleResults from a single JSR223 Sampler. Possibly using BackendListeners http://jmeter.apache.org/usermanual/realtime-results.html