Thanks Björn for writing this up, and also writing up Collected reasons why Prometheus doesn't allow dot as a regular character in metric and label names <https://groups.google.com/g/prometheus-developers/c/4ri-xn7ynK4>. I think it adds a huge amount of value for people looking to participate in discussion! Having read through it all I withdraw my original support for just adding dot to metric names. There are a lot of considerations I did not know about that I agree with thanks to your document.
On Tuesday, May 28, 2024 at 11:17:10 PM UTC+1 Bjoern Rabenstein wrote: > I'm trying to keep things short, as all of this had been discussed > at length before. > > WRT "how to explain UTF-8 support to users": I actually don't think > this is a huge problem. I would frame it "this is like file > names". You can use blanks and slashes in Unix file names, and if you > do, it requires weird quoting or escaping, but that's not a huge > problem in practice. People just don't use them if they care. And if > they have to interact with other file sources, where blanks are > common, they cope. And yes, that means that names from OTel semantic > conventions will always be considered weird, but that's a problem of > OTel, not all the other languages where a dot has a special > meaning. Segue to the next paragraph... > > WRT the dot in OTel semantic conventions: Personally, I'm more > convinced than ever that it was a grave mistake to use dots in the > semantic conventions. I understand the history thereof, but the moment > that OTel self-declared as the overarching standard for all kind of > telemetry, they should have realized that using a character that has a > special meaning or is even an operator in sooooo many languages is a > really really bad idea. This is not just PromQL specific. Originally, > I thought it's infeasible to change the semantic conventions at this > point, but by now, that's exactly what I think OTel should do. If the > dot were an actual operator in OTel (let's say a separator of actual > 1st class namespaces) rather than just a convention within a > technically opaque string, I could see some merit. But as it is not, > it's just annoying and has no benefits whatsoever. > > Despite having said all of that, I don't realistically expect that > OTel is going to change the semantic conventions. So next question is > how to deal with it. There are many reasons why it's a bad idea to > allow the dot in Prometheus metric names, most of them weren't > mentioned in this thread. I won't enumerate them all again. We can do > that if we really want to open that can of worms again. Segue to the > next paragraph... > > In all the discussions we had before, my impression was that the > consensus (in the spirit of RFC 7282) was to not add the dot to the > characters that don't require quoting. As the saying goes, in OSS, a > "no" is temporary and a "yes" is forever. So we can re-open this > debate as often as anyone wishes. If the result is different at some > point in the future, so be it. It's unlikely that I will change my > mind (in fact, as alluded to above, I'm more convinced than ever that > Prometheus should resist the urge). But that doesn't necessarily > prevent an RFC-7282-style consensus. (Or we could also just have a > vote, like in the old days, although that should be a last resort.) > Despite the opinions expressed so far, I would doubt that I'm the only > one who will be opposed. > > Julius has previously described quite nicely how OTel conventions and > practices creep into the Prometheus ecosystem, undermining original > properties of Prometheus as "simple, light-weight, and > opinionated". The whole quoting syntax that opened this thread is for > me a way of allowing what OTel needs but also of containing the damage > and keep things in spirit for normal Prometheus users. Maybe another > thing to include when explaining the syntax to normal Prometheus > users. > > -- > Björn Rabenstein > [PGP-ID] 0x851C3DA17D748D03 > [email] [email protected] > -- You received this message because you are subscribed to the Google Groups "Prometheus Developers" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/prometheus-developers/d14d59cf-204b-4215-afb8-3b5adee96be4n%40googlegroups.com.
