[Metricbeat] Add STAN (NATS streaming) module (#14839)

CHANGELOG.next.asciidoc

@@ -454,6 +454,7 @@ https://github.com/elastic/beats/compare/v7.0.0-alpha2...master[Check the HEAD d
 - Fix timezone parsing in haproxy pipeline. {pull}14755[14755]
 - Add module for ActiveMQ. {pull}14840[14840]
 - Add dashboards for the ActiveMQ Filebeat module. {pull}14880[14880]
+- Add STAN Metricbeat module. {pull}14839[14839]
 
 *Heartbeat*
 - Add non-privileged icmp on linux and darwin(mac). {pull}13795[13795] {issue}11498[11498]

dev-tools/mage/gotest.go

@@ -101,7 +101,10 @@ func GoTest(ctx context.Context, params GoTestArgs) error {
 	fmt.Println(">> go test:", params.TestName, "Testing")
 
 	// Build args list to Go.
-	args := []string{"test", "-v"}
+	args := []string{"test"}
+	if mg.Verbose() {
+		args = append(args, "-v")
+	}
 	if params.Race {
 		args = append(args, "-race")
 	}
@@ -123,9 +126,7 @@ func GoTest(ctx context.Context, params GoTestArgs) error {
 	// Wire up the outputs.
 	bufferOutput := new(bytes.Buffer)
 	outputs := []io.Writer{bufferOutput}
-	if mg.Verbose() {
-		outputs = append(outputs, os.Stdout)
-	}
+
 	if params.OutputFile != "" {
 		fileOutput, err := os.Create(createDir(params.OutputFile))
 		if err != nil {
@@ -135,8 +136,8 @@ func GoTest(ctx context.Context, params GoTestArgs) error {
 		outputs = append(outputs, fileOutput)
 	}
 	output := io.MultiWriter(outputs...)
-	goTest.Stdout = output
-	goTest.Stderr = output
+	goTest.Stdout = io.MultiWriter(output, os.Stdout)
+	goTest.Stderr = io.MultiWriter(output, os.Stderr)
 
 	// Execute 'go test' and measure duration.
 	start := time.Now()

metricbeat/docs/fields.asciidoc

@@ -63,6 +63,7 @@ grouped in the following categories:
 * <<exported-fields-rabbitmq>>
 * <<exported-fields-redis>>
 * <<exported-fields-sql>>
+* <<exported-fields-stan>>
 * <<exported-fields-statsd>>
 * <<exported-fields-system>>
 * <<exported-fields-tomcat>>
@@ -29518,6 +29519,261 @@ type: object
 
 --
 
+[[exported-fields-stan]]
+== Stan fields
+
+stan Module
+
+
+
+[float]
+=== stan
+
+`stan` contains statistics that were read from Nats Streaming server (STAN)
+
+
+
+*`stan.server.id`*::
++
+--
+The server ID
+
+
+type: keyword
+
+--
+
+*`stan.cluster.id`*::
++
+--
+The cluster ID
+
+
+type: keyword
+
+--
+
+[float]
+=== channels
+
+Contains stan / nats streaming/serverz endpoint metrics
+
+
+
+*`stan.channels.name`*::
++
+--
+The name of the STAN streaming channel
+
+
+type: keyword
+
+--
+
+*`stan.channels.messages`*::
++
+--
+The number of STAN streaming messages
+
+
+type: long
+
+--
+
+*`stan.channels.bytes`*::
++
+--
+The number of STAN bytes in the channel
+
+
+type: long
+
+--
+
+*`stan.channels.first_seq`*::
++
+--
+First sequence number stored in the channel. If first_seq > min([seq in subscriptions]) data loss has possibly occurred
+
+
+type: long
+
+--
+
+*`stan.channels.last_seq`*::
++
+--
+Last sequence number stored in the channel
+
+
+type: long
+
+--
+
+*`stan.channels.depth`*::
++
+--
+Queue depth based upon current sequence number and highest reported subscriber sequence number
+
+
+type: long
+
+--
+
+[float]
+=== stats
+
+Contains only high-level stan / nats streaming server related metrics
+
+
+
+*`stan.stats.state`*::
++
+--
+The cluster / streaming configuration state (STANDALONE, CLUSTERED)
+
+
+type: keyword
+
+--
+
+*`stan.stats.role`*::
++
+--
+If clustered, role of this node in the cluster (Leader, Follower, Candidate)
+
+
+type: keyword
+
+--
+
+*`stan.stats.clients`*::
++
+--
+The number of STAN clients
+
+
+type: integer
+
+--
+
+*`stan.stats.subscriptions`*::
++
+--
+The number of STAN streaming subscriptions
+
+
+type: integer
+
+--
+
+*`stan.stats.channels`*::
++
+--
+The number of STAN channels
+
+
+type: integer
+
+--
+
+*`stan.stats.messages`*::
++
+--
+Number of messages across all STAN queues
+
+
+type: long
+
+--
+
+*`stan.stats.bytes`*::
++
+--
+Number of bytes consumed across all STAN queues
+
+
+type: long
+
+--
+
+[float]
+=== subscriptions
+
+Contains stan / nats streaming/serverz endpoint subscription metrics
+
+
+
+*`stan.subscriptions.id`*::
++
+--
+The name of the STAN channel subscription (client_id)
+
+
+type: keyword
+
+--
+
+*`stan.subscriptions.channel`*::
++
+--
+The name of the STAN channel the subscription is associated with
+
+
+type: keyword
+
+--
+
+*`stan.subscriptions.queue`*::
++
+--
+The name of the NATS queue that the STAN channel subscription is associated with, if any
+
+
+type: keyword
+
+--
+
+*`stan.subscriptions.last_sent`*::
++
+--
+Last known sequence number of the subscription that was acked
+
+
+type: long
+
+--
+
+*`stan.subscriptions.pending`*::
++
+--
+Number of pending messages from / to the subscriber
+
+
+type: long
+
+--
+
+*`stan.subscriptions.offline`*::
++
+--
+Is the subscriber marked as offline?
+
+
+type: boolean
+
+--
+
+*`stan.subscriptions.stalled`*::
++
+--
+Is the subscriber known to be stalled?
+
+
+type: boolean
+
+--
+
 [[exported-fields-statsd]]
 == Statsd fields
 

metricbeat/docs/modules/stan.asciidoc

@@ -0,0 +1,55 @@
+////
+This file is generated! See scripts/mage/docs_collector.go
+////
+
+[[metricbeat-module-stan]]
+[role="xpack"]
+== Stan module
+
+beta[]
+
+This is the STAN module. The STAN module uses https://github.com/nats-io/nats-streaming-server/blob/master/server/monitor.go[STAN monitoring server APIs] to collect metrics.
+
+The default metricsets are `channels`, `stats` and `subscriptions`.
+
+[float]
+=== Compatibility
+
+The STAN module is tested with STAN 0.15.1.
+
+
+[float]
+=== Example configuration
+
+The Stan module supports the standard configuration options that are described
+in <<configuration-metricbeat>>. Here is an example configuration:
+
+[source,yaml]
+----
+metricbeat.modules:
+- module: stan
+  metricsets: ["stats", "channels", "subscriptions"]
+  period: 60s
+  hosts: ["localhost:8222"]
+  #stats.metrics_path: "/streaming/serverz"
+  #channels.metrics_path: "/streaming/channelsz"
+  #subscriptions.metrics_path: "/streaming/channelsz" # we retrieve streaming subscriptions with a detailed query param to the channelsz endpoint
+----
+
+[float]
+=== Metricsets
+
+The following metricsets are available:
+
+* <<metricbeat-metricset-stan-channels,channels>>
+
+* <<metricbeat-metricset-stan-stats,stats>>
+
+* <<metricbeat-metricset-stan-subscriptions,subscriptions>>
+
+include::stan/channels.asciidoc[]
+
+include::stan/stats.asciidoc[]
+
+include::stan/subscriptions.asciidoc[]
+

metricbeat/docs/modules/stan/channels.asciidoc

@@ -0,0 +1,24 @@
+////
+This file is generated! See scripts/mage/docs_collector.go
+////
+
+[[metricbeat-metricset-stan-channels]]
+=== Stan channels metricset
+
+beta[]
+
+include::../../../../x-pack/metricbeat/module/stan/channels/_meta/docs.asciidoc[]
+
+This is a default metricset. If the host module is unconfigured, this metricset is enabled by default.
+
+==== Fields
+
+For a description of each field in the metricset, see the
+<<exported-fields-stan,exported fields>> section.
+
+Here is an example document generated by this metricset:
+
+[source,json]
+----
+include::../../../../x-pack/metricbeat/module/stan/channels/_meta/data.json[]
+----