I checked at https://prometheus.io/docs/alerting/latest/configuration/#matcher
AFAICS, it doesn't explicitly mention the behaviour of backslashes in UTF-8 matches. There is a specific note about the fallback behaviour of classic matchers <https://prometheus.io/docs/alerting/latest/configuration/#classic-matchers> though: "However, literal line feed characters are tolerated, as are single \ characters not followed by \, n, or ". They act as a literal backslash in that case." Assuming that UTF-8 matchers strictly require literal backslashes to be doubled (\\), this would explain why your expression was accepted by classic matchers but not UTF-8 matchers. The warning message "To make this input compatible with the UTF-8 matchers parser please make sure all regular expressions and values are double-quoted" could perhaps be improved to mention this possibility. On Friday, 6 December 2024 at 10:45:32 UTC Brian Candler wrote: > A bit more context would be helpful. Did you write: > > matchers: > - applicationid=~"^SNSVC\d{7}$" > > or something else? > > Testing with alertmanager 0.27, I think the problem is around handling of > the backslash. The following is accepted by amtool check-config: > > matchers: > - applicationid=~"^SNSVC\\d{7}$" > > but I've not checked if it matches as expected - you don't want to match a > literal backslash and d! > > This is also what the "suggestion" was telling you from the error message, > but then it's also having to escape things for logfmt logging, which means > double-quotes are preceded by backslash, and backslashes are doubled. When > it says: > suggestion="applicationid=~\"^SNSVC\\\\d{7}$\"" > I think what it's actually suggesting is: > applicationid=~"^SNSVC\\d{7}$" > > Unfortunately, YAML also has its own rules for backslashes. Because of > this complexity, I avoid backslashes in regexps where possible, for example > using [.] instead of \. to match a literal dot. In your case, you could > write: > > matchers: > - applicationid=~"^SNSVC[0-9]{7}$" > > and there would be no ambiguity. > > On Friday, 6 December 2024 at 09:58:28 UTC Chris Burke wrote: > >> Can someone please help explain the following Alertmanager warning. >> I know it's trying to tell me that my value needs to be double-quoted, >> but it already is, so I do not understand what it is complaining about. >> My config: applicationid=~"^SNSVC\d{7}$" >> >> Thanks for any help >> >> ts=2024-12-06T00:44:13.964Z caller=parse.go:176 level=warn >> msg="Alertmanager is moving to a new parser for labels and matchers, and >> this input is incompatible. Alertmanager has instead parsed the input using >> the classic matchers parser as a fallback. To make this input compatible >> with the UTF-8 matchers parser please make sure all regular expressions and >> values are double-quoted. If you are still seeing this message please open >> an issue." input="applicationid=~\"^SNSVC\\d{7}$\"" origin=config >> err="15:29: \"^SNSVC\\d{7}$\": invalid input" >> suggestion="applicationid=~\"^SNSVC\\\\d{7}$\"" >> >> -- You received this message because you are subscribed to the Google Groups "Prometheus Users" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion visit https://groups.google.com/d/msgid/prometheus-users/668ad5b6-dc71-4abd-bc5a-df35b56e189fn%40googlegroups.com.
