prometheus_sysctl_exporter(8): filter output using a regex

Add two options, -i and -e, for filtering prometheus metrics.

Each option takes a regular expression as an argument. The provided
regex will be tested against the prometheus metric name.

The -i option includes metrics matching the given regex.
The -e option excludes metrics matching the given regex.

Sponsored by:   Modirum MDPay
Sponsored by:   Klara Inc.
Reviewed by:	0mp, debdrup
Differential Revision:	https://reviews.freebsd.org/D32269

1 files changed, 17 insertions, 1 deletions

diff --git a/usr.sbin/prometheus_sysctl_exporter/prometheus_sysctl_exporter.8 b/usr.sbin/prometheus_sysctl_exporter/prometheus_sysctl_exporter.8
index f4ac44891ecb..7d73e3cab8cd 100644
--- a/usr.sbin/prometheus_sysctl_exporter/prometheus_sysctl_exporter.8
+++ b/usr.sbin/prometheus_sysctl_exporter/prometheus_sysctl_exporter.8
@@ -22,7 +22,7 @@
 .\" SUCH DAMAGE.
 .\"
 .\" $FreeBSD$
-.Dd December 18, 2016
+.Dd October 7, 2021
 .Dt PROMETHEUS_SYSCTL_EXPORTER 8
 .Os
 .Sh NAME
@@ -31,6 +31,8 @@
 .Sh SYNOPSIS
 .Nm prometheus_sysctl_exporter
 .Op Fl dgh
+.Op Fl e Ar pattern
+.Op Fl i Ar pattern
 .Op Ar prefix ...
 .Sh DESCRIPTION
 Prometheus is a monitoring system that gathers metrics from its targets
@@ -74,12 +76,26 @@ The following options are available:
 .Bl -tag -width indent
 .It Fl d
 Print descriptions of metrics when available.
+.It Fl e Ar pattern
+Same as
+.Fl i ,
+except exclude metrics that match
+.Ar pattern .
 .It Fl g
 Gzip compresses the HTTP response body.
 .It Fl h
 Precede the output with a HTTP response header.
 This flag is required when running this utility through
 .Xr inetd 8 .
+.It Fl i Ar pattern
+If specified, include metrics that match
+.Ar pattern .
+The format of
+.Ar pattern
+is to be a regular expression as described in
+.Xr re_format 7 .
+The provided regular expression is tested against the Prometheus
+metric name.
 .El
 .Sh SEE ALSO
 .Xr cron 8 ,