Used labels and service while calling metrics-rs macros

[Sanskar95]

No description provided.

[Max-Meldrum]

ah didn't catch this one before. Why is the group enabled here?

But could we remove the whole function? And move the registration out of the struct and handle it in the Node.

// in Node::new()
for counter in hardware_metric_group.counters() {
  register_histogram!(counter, "node" => self.descriptor.clone());
}

[Max-Meldrum]

As discussed. no need to have counter variable within the handle_source_error function.
Add something like this where we simply bump the counter if the error is acceptable, but otherwise return Err if it is seen as critical.

match self.handle_source_error(error) {
    Ok(_) => {
        counter += 1; // Acceptable Error, just increase counter
    }
    Err(err) {
        return Err(err); // Critical error 
    }
}

[Sanskar95]

Fixes #231

[Max-Meldrum]

should we be enabling the group here in the constructor?

Well to check that there are no errors yes, but it will start counting. Its probably fine to have it there, but then we should probably move the group.reset()?; before rather than after executing handle_events(...).

#[cfg(feature = "hardware_counters", ... )]
self.hardware_metric_group.reset()?;
 #[cfg(feature = "metrics")]
let start_time = Instant::now();

[Max-Meldrum]

registration should happen in Node::new().

I think we can remove the HardwareMetricGroup now that we operate locally. Also, a lot of code can be removed.

We don't need to reset the group.

for iterators, no need to store the iterator in a variable.

for counter in self.perf_events.counters.iter() {
}
// instead of
let iterator = self.perf_events.counters.iter();
for counter in iterator {

}

The code below has not been verified to compile but should be possible to write it like that.

// Node constructor
#[cfg(all(feature = "hardware_counters", target_os = "linux", not(test)))]
for counter in self.perf_events.counters.iter() {
    register_histogram!(counter.to_string(),"node" => self.descriptor.clone());
}

// handle message

#[cfg(all(feature = "hardware_counters", target_os = "linux", not(test)))]
let mut (group, counters) = {
    let group = Group::new()?;
    let counters = Vec::with_capacity(self.perf_events.counters.len());
    for hardware_counter in self.perf_events.counters.iter() {
        let counter = Builder::new()
                        .group(&mut group)
                        .kind(hardware_counter.get_hardware_kind())
                        .build()?;
                        
        counters.push((hardware_counter.to_string(), counter));
    }
    (group, counters)
};

#[cfg(all(feature = "hardware_counters", target_os = "linux", not(test)))]
group.enable()?;

// do work

#[cfg(all(feature = "hardware_counters", target_os = "linux", not(test)))]
group.disable()?;

#[cfg(all(feature = "hardware_counters", target_os = "linux", not(test)))]
let counts = group.read()?;

#[cfg(all(feature = "hardware_counters", target_os = "linux", not(test)))]
for (metric_name, counter) in counters.iter() {
  histogram!(String::from(metric_name), counts[counter] as f64, "node" => self.descriptor.clone());
}