Add supported versions to nats tests (elastic#16317)

Add a common entry point to nats docker images so we
can use the same docker compose and Dockerfile.
Add supported-versions.yml for nats service.
Add support for 2.1.4.

(cherry picked from commit 46cf3dd)

CHANGELOG.next.asciidoc

@@ -232,6 +232,7 @@ https://github.com/elastic/beats/compare/v7.0.0-alpha2...master[Check the HEAD d
 - Add collecting AuroraDB metrics in rds metricset. {issue}14142[14142] {pull}16004[16004]
 - Reuse connections in SQL module. {pull}16001[16001]
 - Improve the `logstash` module (when `xpack.enabled` is set to `true`) to use the override `cluster_uuid` returned by Logstash APIs. {issue}15772[15772] {pull}15795[15795]
+- Add support for NATS 2.1. {pull}16317[16317]
 
 *Packetbeat*
 

metricbeat/docs/modules/nats.asciidoc

@@ -12,7 +12,7 @@ The default metricsets are `stats`, `connections`, `routes` and `subscriptions`.
 [float]
 === Compatibility
 
-The Nats module is tested with Nats 1.3.0 and 2.0.4
+The Nats module is tested with Nats 1.3.0, 2.0.4 and 2.1.4
 
 
 [float]

metricbeat/module/nats/_meta/Dockerfile.2.0.X → metricbeat/module/nats/_meta/Dockerfile

@@ -4,11 +4,10 @@ FROM nats:$NATS_VERSION
 # create an enhanced container with nc command available since nats is based
 # on scratch image making healthcheck impossible
 FROM alpine:latest
-COPY --from=0 /nats-server /nats-server
-COPY --from=0 nats-server.conf nats-server.conf
+COPY --from=0 / /opt/nats
+COPY run.sh /run.sh
 # Expose client, management, and cluster ports
 EXPOSE 4222 8222 6222
 HEALTHCHECK --interval=1s --retries=10 CMD nc -w 1 0.0.0.0 8222 </dev/null
 # Run via the configuration file
-ENTRYPOINT ["/nats-server"]
-CMD ["-c", "nats-server.conf"]
+CMD ["/run.sh"]

metricbeat/module/nats/_meta/docs.asciidoc

@@ -5,7 +5,7 @@ The default metricsets are `stats`, `connections`, `routes` and `subscriptions`.
 [float]
 === Compatibility
 
-The Nats module is tested with Nats 1.3.0 and 2.0.4
+The Nats module is tested with Nats 1.3.0, 2.0.4 and 2.1.4
 
 
 [float]

metricbeat/module/nats/_meta/run.sh

@@ -0,0 +1,18 @@
+#!/bin/sh
+
+# This script is used with old and new versions of nats,
+# and they use different names for their binaries, detect
+# which one is used and run it.
+
+# NATS 2.X
+if [ -x /opt/nats/nats-server ]; then
+	exec /opt/nats/nats-server -c /opt/nats/nats-server.conf
+fi
+
+# NATS 1.X
+if [ -x /opt/nats/gnatsd ]; then
+	exec /opt/nats/gnatsd -c /opt/nats/gnatsd.conf
+fi
+
+echo "Couldn't find the nats server binary"
+exit 1

metricbeat/module/nats/_meta/supported-versions.yml

@@ -0,0 +1,4 @@
+variants:
+  - NATS_VERSION: 2.1.4
+  - NATS_VERSION: 2.0.4
+  - NATS_VERSION: 1.3.0

metricbeat/module/nats/docker-compose.yml

@@ -5,19 +5,8 @@ services:
     image: docker.elastic.co/integrations-ci/beats-nats:${NATS_VERSION:-2.0.4}-1
     build:
       context: ./_meta
-      dockerfile: Dockerfile.2.0.X
+      dockerfile: Dockerfile
       args:
         NATS_VERSION: ${NATS_VERSION:-2.0.4}
     ports:
       - 8222
-
-  nats_1_3:
-    image: docker.elastic.co/integrations-ci/beats-nats:${NATS_VERSION:-1.3.0}-1
-    build:
-      context: ./_meta
-      dockerfile: Dockerfile.1.3
-      args:
-        NATS_VERSION: ${NATS_VERSION:-1.3.0}
-    ports:
-      - 8222
-

metricbeat/module/nats/test_nats.py

@@ -9,8 +9,8 @@
 NATS_FIELDS = metricbeat.COMMON_FIELDS + ["nats"]
 
 
+@metricbeat.parameterized_with_supported_versions
 class TestNats(metricbeat.BaseTest):
-
     COMPOSE_SERVICES = ['nats']
 
     @unittest.skipUnless(metricbeat.INTEGRATION_TESTS, "integration test")
@@ -112,7 +112,3 @@ def test_subscriptions(self):
         self.assertCountEqual(self.de_dot(NATS_FIELDS), evt.keys(), evt)
 
         self.assert_fields_are_documented(evt)
-
-
-class TestNats1_3(TestNats):
-    COMPOSE_SERVICES = ['nats_1_3']