mtail VS prometheus-cpp

You can do that with something like mtail. Basically write expressions that match your logs and produce metrics.

mtail is a standard tool for this.

I use goflow2 to do something like this. I don't specifically use syslog itself for this, but mtail to generate the metrics.

I can recommend mtail. Here is a good example nginx script.

If not, https://github.com/google/mtail might be a good option.

Count the lines with mtail. You can regexp match the values out into labels.

If you want to extract whitebox metrics from logs, maybe all you need is mtail.

You can use mtail (https://github.com/google/mtail) for this. You'll need to figure out how to plug it into your setup, but mtail will do the metrics from logs thing.

Convert your logs to metrics with mtail.

For nginx, you'll need to setup a log parser like mtail because it doesn't really have much for metrics to begin with.

Rust does have some very cool mechanisms for safety, including in the presence of concurrency.

But this thread is generating blowback from someone saying: “slow down there with the hand-rolled atomic operations, you can hand-roll your multi-threaded locking strategy and it’ll be way safer at a modest cost!”

So, probably not the target audience for Rust ;)

I use a lot of C++ still because there are libraries I want and I have a significant investment in existing code, but I’d love to get to something more modern.

Hand-rolled atomics and load/store relaxation in application code make even seasoned C++ hackers a bit nervous: we saw this shit from business logic hackers at FB all the time and my colleague coined the term “aggressively intermediate” for the style.

I don’t mean to pick on the author of a quite good library (and it is quite good), but I ran across this the other day:

https://github.com/jupp0r/prometheus-cpp/blob/master/core/sr...

It’s correct (I think, very easy to be wrong about this sort of thing), but what are we measuring here where we can’t delegate that CAS into pthread? Branch mispredictions?

Either threads are fighting over whatever cache line that’s on (exclusive -> invalid -> exclusive -> invalid), or not. If they are, I’ve just deprived the scheduler of the opportunity to wake me up when the other 59 threads are done. If they’re not, I’ve maybe saved like one line in my L1.

And in something like a metrics library, you could be wrong for a very long time before someone pinned it down.

Some metric collecting tool, for example, Prometheus and its client library for C++

You can use https://github.com/jupp0r/prometheus-cpp (your custom data) in combination with https://grafana.com/ that has plugins for things like cpu usage.

Grafana and Prometheus is what I’d use if you’re deploying this in Kubernetes. I haven’t used the C++ library, but generally you can just add a Prometheus client library (e.g. https://github.com/jupp0r/prometheus-cpp ) which makes it quite easy to instrument your application and expose metrics via HTTP. Then you need to configure Prometheus to scrape metrics from your application.