randotron

I wrote this because I couldn't find an easy way of randomly executing Rust code. Although this is probably not something that would need to be done on a regular basis, it's useful when you want to execute some code only once every hundred times on average such as metric recording.

At the moment randotron (I couldn't think of a better name), takes a sample rate and a closure:

randotron(100, || { println!("I get printed only 1% of the time!") });

The sample rate is the reciprocal of the intended rate. For example, 100 would mean 1/100, that is, once every hundred times on average. 675 would mean that the code would be executed on average once every six hundred and seventy five times. Many libraries represent this value as a float such that 1% would be 0.01 rather than 100. The approach in randotron uses u64 rather than f64, to keep things simpler.

Evaluation result

randotron will evaluate toSome(result) (where result is what the closure would have evaluated to had it been executed independently) if the closure is chosen for execution. Otherwise randotron will evaluate to None.

Handy sample rates

You can set the sample rate to 1 which will always succeed, effectively ensuring that the closure will run every single time. Similarly although a rate of 0 would normally cause a divide by zero error, in this case it guarantees that the closure will never execute and will always return None.