From 60b380da70213975bfd343be64f5b89b03e2c944 Mon Sep 17 00:00:00 2001 From: Guillaume Berche Date: Wed, 12 Jul 2023 09:08:23 +0200 Subject: [PATCH] Refine functions.md as suggested during review See https://github.com/prometheus/prometheus/pull/11404#issuecomment-1631165746 Signed-off-by: Guillaume Berche --- docs/querying/functions.md | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/docs/querying/functions.md b/docs/querying/functions.md index 3658c10c6..9b58cc319 100644 --- a/docs/querying/functions.md +++ b/docs/querying/functions.md @@ -289,7 +289,7 @@ label_join(up{job="api-server",src1="a",src2="b",src3="c"}, "foo", ",", "src1", ## `label_replace()` For each timeseries in `v`, `label_replace(v instant-vector, dst_label string, replacement string, src_label string, regex string)` -matches the regular expression `regex` against the value of the label `src_label`. If it +matches the [regular expression](https://github.com/google/re2/wiki/Syntax) `regex` against the value of the label `src_label`. If it matches, the value of the label `dst_label` in the returned timeseries will be the expansion of `replacement`, together with the original labels in the input. Capturing groups in the regular expression can be referenced with `$1`, `$2`, etc. Named capturing groups in the regular expression can be referenced with `$name` (where `name` is the capturing group name). If the regular expression doesn't match then the timeseries is returned unchanged. @@ -300,6 +300,10 @@ This example will return timeseries with the values `a:c` at label `service` and label_replace(up{job="api-server",service="a:c"}, "foo", "$1", "service", "(.*):.*") ``` +This second example has the same effect than the first example, and illustrates use of named capturing groups: +``` +label_replace(up{job="api-server",service="a:c"}, "foo", "$name", "service", "(?P.*):(?P.*)") +``` ## `ln()` `ln(v instant-vector)` calculates the natural logarithm for all elements in `v`.