Merge remote-tracking branch 'origin/topic/awelzel/1474-cluster-telemetry'

* origin/topic/awelzel/1474-cluster-telemetry:
  btest/cluster/telemetry: Add smoke testing for telemetry
  cluster/WebSocket: Fetch X-Application-Name header as app label
  cluster/WebSocket: Pass X-Application-Name to dispatcher
  broker/WebSocketShim: Add calls to Telemetry hooks
  cluster/WebSocket: Configure telemetry for WebSocket backends
  broker: Hook up generic cluster telemetry
  cluster: Introduce telemetry component

One bug fix removing static from a variable that shouldn't be static.

scripts/base/frameworks/cluster/__load__.zeek

@@ -1,6 +1,7 @@
 # Load the core cluster support.
 @load ./main
 @load ./pools
+@load ./telemetry
 
 @if ( Cluster::is_enabled() )
 

scripts/base/frameworks/cluster/telemetry.zeek

@@ -0,0 +1,40 @@
+## Module for cluster telemetry.
+module Cluster::Telemetry;
+
+export {
+	type Type: enum {
+		## Creates counter metrics for incoming and for outgoing
+		## events without labels.
+		INFO,
+		## Creates counter metrics for incoming and outgoing events
+		## labeled with handler and normalized topic names.
+		VERBOSE,
+		## Creates histogram metrics using the serialized message size
+		## for events, labeled by topic, handler and script location
+		## (outgoing only).
+		DEBUG,
+	};
+
+	## The telemetry types to enable for the core backend.
+	const core_metrics: set[Type] = {
+		INFO,
+	} &redef;
+
+	## The telemetry types to enable for WebSocket backends.
+	const websocket_metrics: set[Type] = {
+		INFO,
+	} &redef;
+
+	## Table used for normalizing topic names that contain random parts.
+	## Map to an empty string to skip recording a specific metric
+	## completely.
+	const topic_normalizations: table[pattern] of string = {
+		[/^zeek\.cluster\.nodeid\..*/] = "zeek.cluster.nodeid.__normalized__",
+		[/^zeek\/cluster\/nodeid\/.*/] = "zeek/cluster/nodeid/__normalized__",
+	} &ordered &redef;
+
+	## For the DEBUG metrics, the histogram buckets to use.
+	const message_size_bounds: vector of double = {
+		10.0, 50.0, 100.0, 500.0, 1000.0, 5000.0, 10000.0, 50000.0,
+	} &redef;
+}