Introduce metrics_port to supervisor and management framework.

This only adds the port value in the various required places. Its actual use
follows in the next commits.

scripts/base/frameworks/supervisor/api.zeek

@@ -30,6 +30,8 @@ export {
 		## The PCAP file name from which the node will read/analyze packets.
 		## Typically used by worker nodes.
 		pcap_file: string &optional;
+		## The TCP port at which the cluster node exposes metrics for Prometheus.
+		metrics_port: port &optional;
 	};
 
 	## Configuration options that influence behavior of a supervised Zeek node.

scripts/policy/frameworks/management/agent/main.zeek

@@ -521,6 +521,9 @@ function deploy_request_finish(areq: Management::Request::Request)
 		if ( node?$interface )
 			cep$interface = node$interface;
 
+		if ( node?$metrics_port )
+			cep$metrics_port = node$metrics_port;
+
 		g_cluster[node$name] = cep;
 		}
 
@@ -630,6 +633,9 @@ function get_nodes_request_finish(areq: Management::Request::Request)
 			# serialization always assumes TCP.
 			if ( sns$node$cluster[node]$p != 0/tcp )
 				cns$p = sns$node$cluster[node]$p;
+
+			if ( sns$node$cluster[node]?$metrics_port )
+				cns$metrics_port = sns$node$cluster[node]$metrics_port;
 			}
 		else
 			{

scripts/policy/frameworks/management/types.zeek

@@ -60,6 +60,7 @@ export {
 		interface: string &optional;         ##< Interface to sniff
 		cpu_affinity: int &optional;         ##< CPU/core number to pin to
 		env: table[string] of string &default=table(); ##< Custom environment vars
+		metrics_port: port &optional;        ##< Metrics exposure port for Prometheus
 	};
 
 	## Data structure capturing a cluster's complete configuration.
@@ -88,6 +89,8 @@ export {
 		pid: int &optional;
 		## The node's Broker peering listening port, if any.
 		p: port &optional;
+		## The node's metrics port for Prometheus, if any.
+		metrics_port: port &optional;
 	};
 
 	type NodeStatusVec: vector of NodeStatus;