matching: send status updates to NATS -> reduce message redelivery

Author: derhuerst

lib/match.js

@@ -234,6 +234,12 @@ const runGtfsMatching = async (cfg, opt = {}) => {
 				matched: isMatched ? '1' : '0',
 				cached: isCached ? '1' : '0',
 			}, matchingTime / 1000)
+
+			if (!isMatched) {
+				// > Indicate to the JetStream server that processing of the message failed and that the message should not be sent to the consumer again.
+				// https://nats-io.github.io/nats.js/jetstream/interfaces/JsMsg.html#term
+				msg.term()
+			}
 		} catch (err) {
 			if (isProgrammerError(err)) {
 				throw err
@@ -262,6 +268,10 @@ const runGtfsMatching = async (cfg, opt = {}) => {
 			dataSlice: data.slice(0, 100).toString('utf8'),
 		}, 'processing AUS IstFahrt msg')
 
+		// > Indicate to the JetStream server that processing of the message is on going, and that the ack wait timer for the message should be reset preventing a redelivery.
+		// https://nats-io.github.io/nats.js/jetstream/interfaces/JsMsg.html#working
+		msg.working()
+
 		// update NATS metrics
 		{
 			const {