[#2166] Expand Kea name-only UNIX socket paths

Author: andrei-pavel

backend/agent/kea.go

@@ -10,6 +10,7 @@ import (
 	"net/http"
 	"os"
 	"path"
+	"path/filepath"
 	"regexp"
 	"strings"
 
@@ -328,9 +329,19 @@ func (sm *monitor) detectKeaDaemons(ctx context.Context, p supportedProcess) ([]
 			}
 		}
 
+		// Normalize socket path if the socket type is unix. Translate into full path if only name is given.
+		socketAddress := controlSocket.GetAddress()
+		if controlSocket.GetProtocol() == protocoltype.Socket && !strings.Contains(socketAddress, "/") {
+			exe, err := p.getExe()
+			if err != nil {
+				return nil, errors.WithMessagef(err, "could not get path to executable")
+			}
+			socketAddress = filepath.Join(filepath.Dir(exe), "..", "var", "run", "kea", socketAddress)
+		}
+
 		accessPoint := AccessPoint{
 			Type:     AccessPointControl,
-			Address:  controlSocket.GetAddress(),
+			Address:  socketAddress,
 			Port:     controlSocket.GetPort(),
 			Protocol: controlSocket.GetProtocol(),
 			Key:      key,

backend/agent/kea_test.go

@@ -1138,6 +1138,65 @@ func TestDetectKeaDHCPOnSocketPost3_0(t *testing.T) {
 	require.Equal(t, protocoltype.Socket, accessPoint.Protocol)
 }
 
+// Test that the Kea DHCP listening on socket configured with name only is detected.
+func TestDetectKeaDHCPOnSocketNameOnly(t *testing.T) {
+	// Arrange
+	ctrl := gomock.NewController(t)
+	defer ctrl.Finish()
+
+	sb := testutil.NewSandbox()
+	defer sb.Close()
+
+	// Create a configuration file for Kea.
+	configPath, _ := sb.Write("kea-dhcp4.conf", `{
+      "Dhcp4": {
+				"control-socket": {
+					"socket-type": "unix",
+					"socket-name": "kea4-ctrl-socket"
+				}
+			}
+    }`)
+	exePath, _ := sb.Join("kea-dhcp4")
+
+	httpConfig := HTTPClientConfig{}
+
+	// Kea process mock.
+	process := NewMockSupportedProcess(ctrl)
+	process.EXPECT().getName().Return("kea-dhcp4", nil)
+	process.EXPECT().getDaemonName().Return(daemonname.DHCPv4)
+	process.EXPECT().getCmdline().Return(
+		fmt.Sprintf("%s -c %s", exePath, configPath),
+		nil,
+	)
+	process.EXPECT().getCwd().Return(sb.BasePath, nil)
+	process.EXPECT().getExe().Return(sb.BasePath, nil)
+
+	// System calls mock.
+	commander := NewMockCommandExecutor(ctrl)
+	commander.EXPECT().Output(exePath, "-v").Return([]byte("3.0.0\n"), nil)
+
+	monitor := newMonitor("", "", httpConfig)
+	monitor.commander = commander
+
+	// Act
+	daemons, err := monitor.detectKeaDaemons(t.Context(), process)
+
+	// Assert
+	require.False(t, gock.HasUnmatchedRequest())
+	require.NoError(t, err)
+
+	require.Len(t, daemons, 1)
+	require.Equal(t, daemonname.DHCPv4, daemons[0].GetName())
+
+	accessPoints := daemons[0].GetAccessPoints()
+	require.Len(t, accessPoints, 1)
+	accessPoint := accessPoints[0]
+	require.Equal(t, AccessPointControl, accessPoint.Type)
+	require.Equal(t, "/var/run/kea/kea4-ctrl-socket", accessPoint.Address)
+	require.Zero(t, accessPoint.Port)
+	require.Equal(t, protocoltype.Socket, accessPoint.Protocol)
+}
+
 // Test that the Kea DHCP post 3.0 listening on HTTP is detected.
 func TestDetectKeaDHCPOnHTTPPost3_0(t *testing.T) {
 	// Arrange

backend/agent/process.go

@@ -18,6 +18,7 @@ var (
 type supportedProcess interface {
 	getCmdline() (string, error)
 	getCwd() (string, error)
+	getExe() (string, error)
 	getName() (string, error)
 	getPid() int32
 	getParentPid() (int32, error)
@@ -44,6 +45,13 @@ func (p *processWrapper) getCwd() (string, error) {
 	return cwd, err
 }
 
+// Returns the process path to the executable.
+func (p *processWrapper) getExe() (string, error) {
+	exe, err := p.process.Exe()
+	err = errors.Wrapf(err, "failed to get process executable path for pid %d", p.getPid())
+	return exe, err
+}
+
 // Returns the process pid.
 func (p *processWrapper) getPid() int32 {
 	return p.process.Pid

changelog_unreleased/2166-detect-default-paths-from-kea-config.md

@@ -0,0 +1,5 @@
+[func] andrei
+
+    The agent can now communicate to UNIX control sockets if they are
+    configured by name only in Kea.
+    (Gitlab #2166)