Fix incorrect usage of hints builder when exposed port is a substring of the hint

CHANGELOG.next.asciidoc

@@ -237,6 +237,7 @@ https://github.com/elastic/beats/compare/v7.0.0-alpha2...master[Check the HEAD d
 - Add missing network.sent_packets_count metric into compute metricset in googlecloud module. {pull}18802[18802]
 - Fix compute and pubsub dashboard for googlecloud module. {issue}18962[18962] {pull}18980[18980]
 - Fix crash on vsphere module when Host information is not available. {issue}18996[18996] {pull}19078[19078]
+- Fix incorrect usage of hints builder when exposed port is a substring of the hint {pull}19052[19052]
 
 *Packetbeat*
 

metricbeat/autodiscover/builder/hints/metrics.go

@@ -19,6 +19,7 @@ package hints
 
 import (
 	"fmt"
+	"strconv"
 	"strings"
 
 	"github.com/elastic/go-ucfg"
@@ -187,7 +188,7 @@ func (m *metricHints) getHostsWithPort(hints common.MapStr, port int) ([]string,
 	// Only pick hosts that have ${data.port} or the port on current event. This will make
 	// sure that incorrect meta mapping doesn't happen
 	for _, h := range thosts {
-		if strings.Contains(h, "data.port") || strings.Contains(h, fmt.Sprintf(":%d", port)) ||
+		if strings.Contains(h, "data.port") || m.checkHostPort(h, port) ||
 			// Use the event that has no port config if there is a ${data.host}:9090 like input
 			(port == 0 && strings.Contains(h, "data.host")) {
 			result = append(result, h)
@@ -202,6 +203,27 @@ func (m *metricHints) getHostsWithPort(hints common.MapStr, port int) ([]string,
 	return result, true
 }
 
+func (m *metricHints) checkHostPort(h string, p int) bool {
+	port := strconv.Itoa(p)
+
+	index := strings.LastIndex(h, ":"+port)
+	// Check if host contains :port. If not then return false
+	if index == -1 {
+		return false
+	}
+
+	// Check if the host ends with :port. Return true if yes
+	end := index + len(port) + 1
+	if end == len(h) {
+		return true
+	}
+
+	// Check if the character immediately after :port. If its not a number then return true.
+	// This is to avoid adding :80 as a valid host for an event that has port=8080
+	// Also ensure that port=3306 and hint="tcp(${data.host}:3306)/" is valid
+	return h[end] < '0' || h[end] > '9'
+}
+
 func (m *metricHints) getNamespace(hints common.MapStr) string {
 	return builder.GetHintString(hints, m.Key, namespace)
 }

metricbeat/autodiscover/builder/hints/metrics_test.go

@@ -290,6 +290,45 @@ func TestGenerateHints(t *testing.T) {
 				"enabled":    true,
 			},
 		},
+		{
+			message: "Module, namespace, host hint shouldn't return when port isn't the same has hint",
+			event: bus.Event{
+				"host": "1.2.3.4",
+				"port": 80,
+				"hints": common.MapStr{
+					"metrics": common.MapStr{
+						"module":    "mockmoduledefaults",
+						"namespace": "test",
+						"hosts":     "${data.host}:8080",
+					},
+				},
+			},
+			len: 0,
+		},
+		{
+			message: "Non http URLs with valid host port combination should return a valid config",
+			event: bus.Event{
+				"host": "1.2.3.4",
+				"port": 3306,
+				"hints": common.MapStr{
+					"metrics": common.MapStr{
+						"module":    "mockmoduledefaults",
+						"namespace": "test",
+						"hosts":     "tcp(${data.host}:3306)/",
+					},
+				},
+			},
+			len: 1,
+			result: common.MapStr{
+				"module":     "mockmoduledefaults",
+				"namespace":  "test",
+				"metricsets": []string{"default"},
+				"hosts":      []interface{}{"tcp(1.2.3.4:3306)/"},
+				"timeout":    "3s",
+				"period":     "1m",
+				"enabled":    true,
+			},
+		},
 	}
 	for _, test := range tests {
 		mockRegister := mb.NewRegister()