added counter and delay for load testing

[saumilsdk]

Added counter to send the same message multiple times to generate load using same connection. Delay is used to delay the messages set in counter.

[njh]

I am not sure about adding the new --count option - not sure how widely useful it is for other people. For sending lots of packets for load testing, you could pass in lots of packets to STDIN with the -l option. Would that work for you? It also has the advantage that you could send a variety of packets if you wanted to.

Although I can see how it might be useful to add a delay between publishing messages. Please can you create a separate PR for just adding --delay? - for use within this loop: https://github.com/njh/mqtt-sn-tools/blob/master/mqtt-sn-pub.c#L227

Also you have done some code style changes in this PR, not just new features. The code style for this project is:

• K&R style
• Indented 4 spaces
• Switch and case statements should be indented

Thanks!

ps. what are you load testing? 🙂

[saumilsdk]

@njh I had to load test MQTT-SN server along with number of messages a server with limited resources like 2GB RAM and 1 core can take how many messages. Count is really helpful in sending messages along with use of delay. I would recommend to have both options enabled.

I will also change back formatting style to what you are recommending.

[njh]

Thanks for the update.

I am sure it is useful to be able to load test and specify a number of packets to send. But I am not sure it should be in the main mqtt-sn-pub.c as it is specific to load testing and adds complexity.

I am wondering about having a separate load test tool (mqtt-sn-load-test?) that is specifically for this purpose. It could just be a wrapper round mqtt-sn-pub and could either be a bash script of C programme.