Document how to specify multiple excludeMetrics
The documentation mentions multiple patterns can be given by repeating
the `excludeMetrics` setting but it was unclear to me how to proceed.
The setting is fetched using a getStringList() which comes from jgit and
indeed one just need to repeat it. An example makes it clearer.
I also thought the matching was to be done against the metric names
exposed to Prometheus, but it is instead done against the Gerrit metric
name (`/` separated).
The doc mentions the matching is done on the whole key, document that it
is internally using `regex.Matcher.matches()` (and not `lookingAt()`
which matches at the start of the subject). The multiple values
example does use a lead carret '^' which indicates matching at the start
of metric name has to be set explicitly.
Change-Id: I89fd2d4bb6523446ba54f741767336f907c800ac
diff --git a/src/main/resources/Documentation/config.md b/src/main/resources/Documentation/config.md
index 070151f..6c41974 100644
--- a/src/main/resources/Documentation/config.md
+++ b/src/main/resources/Documentation/config.md
@@ -25,11 +25,29 @@
for how to configure the integration with Prometheus.
plugin.@PLUGIN@.excludeMetrics
-: Regex pattern used to exclude metrics from the report. It can be specified multiple times.
- Note that pattern matching is done on the whole metric name, not only on a part of it.
- By default no metric is excluded.
- For example, to exclude all cache metrics, use: `excludeMetrics = cache.*`
+: Regex pattern used to exclude metrics from the report.
+ The matching is done against the Gerrit metrics names as documented on
+ ['Metrics'](@URL@Documentation/metrics.html). The pattern matching is done
+ internally using `regex.Matcher.matches()` and can match anywhere (not
+ necessarly starting at the beginning of the metric name)
+
+ By default no metric is excluded.
+
+ For examples:
+
+ To exclude all metrics matching `cache` at some place in their key, use:
+ `excludeMetrics = cache.*`
+
+ To exclude multiple metrics:
+ ```
+ [plugin "metrics-reporter-prometheus"]
+ excludeMetrics = ^http/server/rest_api/.*
+ excludeMetrics = ^license/cla_check_count
+ excludeMetrics = ^plugin/latency/.*
+ excludeMetrics = ^reviewer_suggestion/.*
+ excludeMetrics = ^sequence/next_id_latency.*
+ ```
[Back to @PLUGIN@ documentation index][index]
