metrics: allow changing influxdb interval

[cskiraly]

The PR exposes the InfuxDB reporting interval as a CLI parameter, which was previously fixed 10s.
Default is still kept at 10s.
Note that decreasing the interval comes with notable extra traffic and load on InfluxDB.

[rjl493456442]

We can sanitize the interval if it's too small.

diff --git a/cmd/utils/flags.go b/cmd/utils/flags.go
index d6e8112bee..87c9567b3d 100644
--- a/cmd/utils/flags.go
+++ b/cmd/utils/flags.go
@@ -2178,6 +2178,13 @@ func SetupMetrics(cfg *metrics.Config) {
 		tagsMap      = SplitTagsFlag(cfg.InfluxDBTags)
 		interval     = cfg.InfluxDBInterval
 	)
+
+	// Sanitize the report interval
+	if interval < time.Second {
+		log.Warn("Sanitizing influxDB report interval", "provided", common.PrettyDuration(interval), "updated", common.PrettyDuration(time.Second))
+		interval = time.Second
+	}
+
 	if enableExport {
 		log.Info("Enabling metrics export to InfluxDB", "interval", interval)
 		go influxdb.InfluxDBWithTags(metrics.DefaultRegistry, interval, endpoint, database, username, password, "geth.", tagsMap)

[cskiraly]

We can sanitize the interval if it's too small.

Why would we do that, and why set to min 1 second? If you set this low, my assumption would be that you do it on purpose.