Don't generate autodiscover config when no port matches host hints

On metricbeat, when the host autodiscover hint is used, and it includes the port, one of the exposed ports has to match with the one in the hint. If not, no configuration should be generated. If it is generated, it will have empty hosts, what would lead to unexpected errors as the seen in elastic#8264.
jsoriano · May 6, 2019 · 675d605 · 675d605
1 parent 431a589
commit 675d605
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Showing 3 changed files with 30 additions and 5 deletions.
diff --git a/CHANGELOG.next.asciidoc b/CHANGELOG.next.asciidoc
@@ -104,6 +104,7 @@ https://github.com/elastic/beats/compare/v7.0.0-alpha2...master[Check the HEAD d
 - Change diskio metrics retrieval method (only for Windows) from wmi query to DeviceIOControl function using the IOCTL_DISK_PERFORMANCE control code {pull}11635[11635]
 - Call GetMetricData api per region instead of per instance. {issue}11820[11820] {pull}11882[11882]
 - Update documentation with cloudwatch:ListMetrics permission. {pull}11987[11987]
+- Avoid generating hints-based configuration with empty hosts when no exposed port is suitable for the hosts hint. {issue}8264[8264] {pull}[]
 
 *Packetbeat*
 

diff --git a/metricbeat/autodiscover/builder/hints/metrics.go b/metricbeat/autodiscover/builder/hints/metrics.go
@@ -101,7 +101,11 @@ func (m *metricHints) CreateConfig(event bus.Event) []*common.Config {
 		return config
 	}
 
-	hsts := m.getHostsWithPort(hints, port)
+	hosts, ok := m.getHostsWithPort(hints, port)
+	if !ok {
+		return config
+	}
+
 	ns := m.getNamespace(hints)
 	msets := m.getMetricSets(hints, mod)
 	tout := m.getTimeout(hints)
@@ -112,7 +116,7 @@ func (m *metricHints) CreateConfig(event bus.Event) []*common.Config {
 	moduleConfig := common.MapStr{
 		"module":     mod,
 		"metricsets": msets,
-		"hosts":      hsts,
+		"hosts":      hosts,
 		"timeout":    tout,
 		"period":     ival,
 		"enabled":    true,
@@ -161,7 +165,7 @@ func (m *metricHints) getMetricSets(hints common.MapStr, module string) []string
 	return msets
 }
 
-func (m *metricHints) getHostsWithPort(hints common.MapStr, port int) []string {
+func (m *metricHints) getHostsWithPort(hints common.MapStr, port int) ([]string, bool) {
 	var result []string
 	thosts := builder.GetHintAsList(hints, m.Key, hosts)
 
@@ -175,7 +179,12 @@ func (m *metricHints) getHostsWithPort(hints common.MapStr, port int) []string {
 		}
 	}
 
-	return result
+	if len(thosts) > 0 && len(result) == 0 {
+		logp.Debug("hints.builder", "no hosts selected for port %d with hints: %+v", port, thosts)
+		return nil, false
+	}
+
+	return result, true
 }
 
 func (m *metricHints) getNamespace(hints common.MapStr) string {

diff --git a/metricbeat/autodiscover/builder/hints/metrics_test.go b/metricbeat/autodiscover/builder/hints/metrics_test.go
@@ -67,6 +67,21 @@ func TestGenerateHints(t *testing.T) {
 			len:    0,
 			result: common.MapStr{},
 		},
+		{
+			message: "Hints without matching port should return nothing",
+			event: bus.Event{
+				"host": "1.2.3.4",
+				"port": 9090,
+				"hints": common.MapStr{
+					"metrics": common.MapStr{
+						"module": "mockmoduledefaults",
+						"hosts":  "${data.host}:8888",
+					},
+				},
+			},
+			len:    0,
+			result: common.MapStr{},
+		},
 		{
 			message: "Only module hint should return all metricsets",
 			event: bus.Event{
@@ -87,7 +102,7 @@ func TestGenerateHints(t *testing.T) {
 			},
 		},
 		{
-			message: "metricsets hint works",
+			message: "Metricsets hint works",
 			event: bus.Event{
 				"host": "1.2.3.4",
 				"hints": common.MapStr{