fixed docker discovery issue where ip address was overwritten (#1201)

* fixed docker discovery issue where ip address was overwritten

* cleanup

pkg/databind/internal/discovery/docker/docker.go

@@ -5,6 +5,7 @@ package docker
 
 import (
 	"context"
+	"net"
 	"sort"
 	"strconv"
 	"strings"
@@ -40,8 +41,6 @@ func Discoverer(d discovery.Container) (fetchDiscoveries func() (discoveries []d
 }
 
 func fetch(d discovery.Container, matcher *discovery.FieldsMatcher) ([]discovery.Discovery, error) {
-	var matches []discovery.Discovery
-
 	dc, err := client.NewClientWithOpts(client.FromEnv, client.WithAPIVersionNegotiation())
 	if err != nil {
 		return nil, err
@@ -53,6 +52,13 @@ func fetch(d discovery.Container, matcher *discovery.FieldsMatcher) ([]discovery
 		return nil, err
 	}
 
+	return getDiscoveries(containers, matcher), nil
+}
+
+// getDiscoveries will filter container list to only the ones that match the config and extract discovery variables from those.
+func getDiscoveries(containers []types.Container, matcher *discovery.FieldsMatcher) []discovery.Discovery {
+	var matches []discovery.Discovery
+
 	for _, cont := range containers {
 		// discovery attributes that identify the container
 		labels := map[string]string{}
@@ -106,8 +112,7 @@ func fetch(d discovery.Container, matcher *discovery.FieldsMatcher) ([]discovery
 			})
 		}
 	}
-
-	return matches, nil
+	return matches
 }
 
 func addPorts(cont types.Container, labels map[string]string) {
@@ -123,20 +128,24 @@ func addPorts(cont types.Container, labels map[string]string) {
 	for index, port := range cont.Ports {
 		indexStr := "." + strconv.Itoa(index)
 		labels[data.IP+indexStr] = port.IP
-		labels[data.IP] = port.IP
-
 		tIdx := types.Count(port.Type)
+
 		publicPort := strconv.Itoa(int(port.PublicPort))
 		privatePort := strconv.Itoa(int(port.PrivatePort))
-		if firstPublic {
+
+		if firstPublic && port.PublicPort > 0 && isIPv4(port.IP) {
+			labels[data.IP] = port.IP
 			labels[data.Port] = publicPort
 			firstPublic = false
 		}
+
 		labels[data.Ports+indexStr] = publicPort
+
 		if firstPrivate {
 			labels[data.PrivatePort] = privatePort
 			firstPrivate = false
 		}
+
 		labels[data.PrivatePorts+indexStr] = privatePort
 
 		// label ports by type (e.g. discovery.port.tcp.1)
@@ -150,3 +159,8 @@ func addPorts(cont types.Container, labels map[string]string) {
 		}
 	}
 }
+
+// isIPv4 returns true if ip string has a IPv4 format.
+func isIPv4(ip string) bool {
+	return net.ParseIP(ip).To4() != nil
+}

pkg/databind/internal/discovery/docker/docker_test.go

@@ -0,0 +1,150 @@
+package docker
+
+import (
+	"github.com/docker/docker/api/types"
+	"github.com/docker/docker/api/types/network"
+	"github.com/newrelic/infrastructure-agent/pkg/databind/internal/discovery"
+	"github.com/newrelic/infrastructure-agent/pkg/databind/pkg/data"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+	"testing"
+)
+
+func TestGetMatchingContainers(t *testing.T) {
+	givenContainerList := []types.Container{
+		{
+			ID: "484c2678906bed94a51fe12ec1fc8ac55f177453dba00c1b0ae0a22f4b655e41",
+			Names: []string{
+				"/sharp_beaver",
+			},
+			Image:   "test-server",
+			ImageID: "sha256:8282995409c26b82d66243f169f6695115a06ce860966db549f8ca09dcbb9767",
+			Command: "/bin/bash -c 'java ${JAVA_OPTS} -jar /test-server.jar'",
+			Created: 1653916418,
+			Ports: []types.Port{
+				{
+					IP:          "0.0.0.0",
+					PrivatePort: 7199,
+					PublicPort:  7199,
+					Type:        "tcp",
+				},
+				{
+					IP:          "",
+					PrivatePort: 4567,
+					PublicPort:  0,
+					Type:        "tcp",
+				},
+			},
+			SizeRw:     0,
+			SizeRootFs: 0,
+			Labels:     map[string]string{},
+			State:      "running",
+			Status:     "Up 8 minutes",
+			HostConfig: struct {
+				NetworkMode string "json:\",omitempty\""
+			}{
+				NetworkMode: "default",
+			},
+			NetworkSettings: &types.SummaryNetworkSettings{
+				Networks: map[string]*network.EndpointSettings{
+					"bridge": {
+						IPAMConfig:          (*network.EndpointIPAMConfig)(nil),
+						Links:               []string(nil),
+						Aliases:             []string(nil),
+						NetworkID:           "e0effada2c3eab26fb73188d0193952ef9a3c985e64cabd76c95196000405418",
+						EndpointID:          "8e143f019bb8549a5594a31058c077eb774960b9b825f819f9593ab57a591f71",
+						Gateway:             "172.17.0.1",
+						IPAddress:           "172.17.0.2",
+						IPPrefixLen:         16,
+						IPv6Gateway:         "",
+						GlobalIPv6Address:   "",
+						GlobalIPv6PrefixLen: 0,
+						MacAddress:          "02:42:ac:11:00:02",
+						DriverOpts:          map[string]string(nil),
+					},
+				},
+			},
+
+			Mounts: []types.MountPoint{},
+		},
+	}
+
+	expectedDiscoveryData := []discovery.Discovery{
+		{
+			Variables: data.Map{
+				"discovery.containerId":         "484c2678906bed94a51fe12ec1fc8ac55f177453dba00c1b0ae0a22f4b655e41",
+				"discovery.image":               "test-server",
+				"discovery.ip":                  "0.0.0.0",
+				"discovery.ip.0":                "",
+				"discovery.ip.1":                "0.0.0.0",
+				"discovery.name":                "sharp_beaver",
+				"discovery.port":                "7199",
+				"discovery.ports.0":             "0",
+				"discovery.ports.1":             "7199",
+				"discovery.ports.tcp":           "0",
+				"discovery.ports.tcp.0":         "0",
+				"discovery.ports.tcp.1":         "7199",
+				"discovery.private.ip":          "172.17.0.2",
+				"discovery.private.ip.0":        "172.17.0.2",
+				"discovery.private.port":        "4567",
+				"discovery.private.ports.0":     "4567",
+				"discovery.private.ports.1":     "7199",
+				"discovery.private.ports.tcp":   "4567",
+				"discovery.private.ports.tcp.0": "4567",
+				"discovery.private.ports.tcp.1": "7199",
+			},
+			MetricAnnotations: data.InterfaceMap{
+				"command":       "/bin/bash -c 'java ${JAVA_OPTS} -jar /test-server.jar'",
+				"containerId":   "484c2678906bed94a51fe12ec1fc8ac55f177453dba00c1b0ae0a22f4b655e41",
+				"containerName": "sharp_beaver",
+				"image":         "test-server",
+				"imageId":       "sha256:8282995409c26b82d66243f169f6695115a06ce860966db549f8ca09dcbb9767",
+				"label":         map[string]string{}},
+			EntityRewrites: []data.EntityRewrite{
+				{
+					Action:       "replace",
+					Match:        "${ip}",
+					ReplaceField: "container:${containerId}",
+				},
+			},
+		},
+	}
+
+	matcher, err := discovery.NewMatcher(map[string]string{
+		"image": "/test-server/",
+	})
+	require.NoError(t, err)
+
+	actualDiscoveryData := getDiscoveries(givenContainerList, &matcher)
+	assert.Equal(t, expectedDiscoveryData, actualDiscoveryData)
+}
+
+func TestIsIPv4(t *testing.T) {
+	testCases := []struct {
+		name     string
+		ip       string
+		expected bool
+	}{
+		{
+			name:     "ValidIpV4",
+			ip:       "127.0.0.1",
+			expected: true,
+		},
+		{
+			name:     "EmptyIp",
+			ip:       "",
+			expected: false,
+		},
+		{
+			name:     "IpV6",
+			ip:       "0000:0000:0000:0000:0000:0000:0000:0001",
+			expected: false,
+		},
+	}
+
+	for _, testCase := range testCases {
+		t.Run(testCase.name, func(t *testing.T) {
+			assert.Equal(t, testCase.expected, isIPv4(testCase.ip))
+		})
+	}
+}