TUN-8730: implement diag/configuration

Implements the endpoint that retrieves the configuration of a running instance.

The configuration consists in a map of cli flag to the provided value along with the uid that of the user that started the process

cmd/cloudflared/tunnel/cmd.go

@@ -127,6 +127,92 @@ var (
 		"most likely you already have a conflicting record there. You can also rerun this command with --%s to overwrite "+
 		"any existing DNS records for this hostname.", overwriteDNSFlag)
 	deprecatedClassicTunnelErr = fmt.Errorf("Classic tunnels have been deprecated, please use Named Tunnels. (https://developers.cloudflare.com/cloudflare-one/connections/connect-apps/install-and-setup/tunnel-guide/)")
+	nonSecretFlagsList         = []string{
+		"config",
+		"autoupdate-freq",
+		"no-autoupdate",
+		"metrics",
+		"pidfile",
+		"url",
+		"hello-world",
+		"socks5",
+		"proxy-connect-timeout",
+		"proxy-tls-timeout",
+		"proxy-tcp-keepalive",
+		"proxy-no-happy-eyeballs",
+		"proxy-keepalive-connections",
+		"proxy-keepalive-timeout",
+		"proxy-connection-timeout",
+		"proxy-expect-continue-timeout",
+		"http-host-header",
+		"origin-server-name",
+		"unix-socket",
+		"origin-ca-pool",
+		"no-tls-verify",
+		"no-chunked-encoding",
+		"http2-origin",
+		"management-hostname",
+		"service-op-ip",
+		"local-ssh-port",
+		"ssh-idle-timeout",
+		"ssh-max-timeout",
+		"bucket-name",
+		"region-name",
+		"s3-url-host",
+		"host-key-path",
+		"ssh-server",
+		"bastion",
+		"proxy-address",
+		"proxy-port",
+		"loglevel",
+		"transport-loglevel",
+		"logfile",
+		"log-directory",
+		"trace-output",
+		"proxy-dns",
+		"proxy-dns-port",
+		"proxy-dns-address",
+		"proxy-dns-upstream",
+		"proxy-dns-max-upstream-conns",
+		"proxy-dns-bootstrap",
+		"is-autoupdated",
+		"edge",
+		"region",
+		"edge-ip-version",
+		"edge-bind-address",
+		"cacert",
+		"hostname",
+		"id",
+		"lb-pool",
+		"api-url",
+		"metrics-update-freq",
+		"tag",
+		"heartbeat-interval",
+		"heartbeat-count",
+		"max-edge-addr-retries",
+		"retries",
+		"ha-connections",
+		"rpc-timeout",
+		"write-stream-timeout",
+		"quic-disable-pmtu-discovery",
+		"quic-connection-level-flow-control-limit",
+		"quic-stream-level-flow-control-limit",
+		"label",
+		"grace-period",
+		"compression-quality",
+		"use-reconnect-token",
+		"dial-edge-timeout",
+		"stdin-control",
+		"name",
+		"ui",
+		"quick-service",
+		"max-fetch-size",
+		"post-quantum",
+		"management-diagnostics",
+		"protocol",
+		"overwrite-dns",
+		"help",
+	}
 )
 
 func Flags() []cli.Flag {
@@ -465,7 +551,16 @@ func StartServer(
 		observer.RegisterSink(tracker)
 
 		readinessServer := metrics.NewReadyServer(clientID, tracker)
-		diagnosticHandler := diagnostic.NewDiagnosticHandler(log, 0, diagnostic.NewSystemCollectorImpl(buildInfo.CloudflaredVersion), tunnelConfig.NamedTunnel.Credentials.TunnelID, clientID, tracker)
+		diagnosticHandler := diagnostic.NewDiagnosticHandler(
+			log,
+			0,
+			diagnostic.NewSystemCollectorImpl(buildInfo.CloudflaredVersion),
+			tunnelConfig.NamedTunnel.Credentials.TunnelID,
+			clientID,
+			tracker,
+			c,
+			nonSecretFlagsList,
+		)
 		metricsConfig := metrics.Config{
 			ReadyServer:         readinessServer,
 			DiagnosticHandler:   diagnosticHandler,

diagnostic/consts.go

@@ -7,4 +7,6 @@ const (
 	collectorField             = "collector"      // used for logging purposes
 	systemCollectorName        = "system"         // used for logging purposes
 	tunnelStateCollectorName   = "tunnelState"    // used for logging purposes
+	configurationCollectorName = "configuration"  // used for logging purposes
+	configurationKeyUid        = "uid"
 )

diagnostic/handlers.go

@@ -4,11 +4,16 @@ import (
 	"context"
 	"encoding/json"
 	"net/http"
+	"os"
+	"path/filepath"
+	"strconv"
 	"time"
 
 	"github.com/google/uuid"
 	"github.com/rs/zerolog"
+	"github.com/urfave/cli/v2"
 
+	"github.com/cloudflare/cloudflared/logger"
 	"github.com/cloudflare/cloudflared/tunnelstate"
 )
 
@@ -19,6 +24,8 @@ type Handler struct {
 	tunnelID          uuid.UUID
 	connectorID       uuid.UUID
 	tracker           *tunnelstate.ConnTracker
+	cli               *cli.Context
+	flagInclusionList []string
 }
 
 func NewDiagnosticHandler(
@@ -28,6 +35,8 @@ func NewDiagnosticHandler(
 	tunnelID uuid.UUID,
 	connectorID uuid.UUID,
 	tracker *tunnelstate.ConnTracker,
+	cli *cli.Context,
+	flagInclusionList []string,
 ) *Handler {
 	logger := log.With().Logger()
 	if timeout == 0 {
@@ -41,6 +50,8 @@ func NewDiagnosticHandler(
 		tunnelID:          tunnelID,
 		connectorID:       connectorID,
 		tracker:           tracker,
+		cli:               cli,
+		flagInclusionList: flagInclusionList,
 	}
 }
 
@@ -110,8 +121,77 @@ func (handler *Handler) TunnelStateHandler(writer http.ResponseWriter, _ *http.R
 	}
 }
 
-func writeResponse(writer http.ResponseWriter, bytes []byte, logger *zerolog.Logger) {
+func (handler *Handler) ConfigurationHandler(writer http.ResponseWriter, _ *http.Request) {
-	bytesWritten, err := writer.Write(bytes)
+	log := handler.log.With().Str(collectorField, configurationCollectorName).Logger()
+	log.Info().Msg("Collection started")
+
+	defer func() {
+		log.Info().Msg("Collection finished")
+	}()
+
+	flagsNames := handler.cli.FlagNames()
+	flags := make(map[string]string, len(flagsNames))
+
+	for _, flag := range flagsNames {
+		value := handler.cli.String(flag)
+
+		// empty values are not relevant
+		if value == "" {
+			continue
+		}
+
+		// exclude flags that are sensitive
+		isIncluded := handler.isFlagIncluded(flag)
+		if !isIncluded {
+			continue
+		}
+
+		switch flag {
+		case logger.LogDirectoryFlag:
+		case logger.LogFileFlag:
+			{
+				// the log directory may be relative to the instance thus it must be resolved
+				absolute, err := filepath.Abs(value)
+				if err != nil {
+					handler.log.Error().Err(err).Msgf("could not convert %s path to absolute", flag)
+				} else {
+					flags[flag] = absolute
+				}
+			}
+		default:
+			flags[flag] = value
+		}
+	}
+
+	// The UID is included to help the
+	// diagnostic tool to understand
+	// if this instance is managed or not.
+	flags[configurationKeyUid] = strconv.Itoa(os.Getuid())
+	encoder := json.NewEncoder(writer)
+
+	err := encoder.Encode(flags)
+	if err != nil {
+		handler.log.Error().Err(err).Msgf("error occurred whilst serializing response")
+		writer.WriteHeader(http.StatusInternalServerError)
+	}
+}
+
+func (handler *Handler) isFlagIncluded(flag string) bool {
+	isIncluded := false
+
+	for _, include := range handler.flagInclusionList {
+		if include == flag {
+			isIncluded = true
+
+			break
+		}
+	}
+
+	return isIncluded
+}
+
+func writeResponse(w http.ResponseWriter, bytes []byte, logger *zerolog.Logger) {
+	bytesWritten, err := w.Write(bytes)
 	if err != nil {
 		logger.Error().Err(err).Msg("error occurred writing response")
 	} else if bytesWritten != len(bytes) {

diagnostic/handlers_test.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"encoding/json"
 	"errors"
+	"flag"
 	"io"
 	"net"
 	"net/http"
@@ -14,6 +15,7 @@ import (
 	"github.com/rs/zerolog"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
+	"github.com/urfave/cli/v2"
 
 	"github.com/cloudflare/cloudflared/connection"
 	"github.com/cloudflare/cloudflared/diagnostic"
@@ -28,6 +30,21 @@ const (
 	errorKey             = "errkey"
 )
 
+func buildCliContext(t *testing.T, flags map[string]string) *cli.Context {
+	t.Helper()
+
+	flagSet := flag.NewFlagSet("", flag.PanicOnError)
+	ctx := cli.NewContext(cli.NewApp(), flagSet, nil)
+
+	for k, v := range flags {
+		flagSet.String(k, v, "")
+		err := ctx.Set(k, v)
+		require.NoError(t, err)
+	}
+
+	return ctx
+}
+
 func newTrackerFromConns(t *testing.T, connections []tunnelstate.IndexedConnectionInfo) *tunnelstate.ConnTracker {
 	t.Helper()
 
@@ -45,6 +62,7 @@ func newTrackerFromConns(t *testing.T, connections []tunnelstate.IndexedConnecti
 
 	return tracker
 }
+
 func setCtxValuesForSystemCollector(
 	systemInfo *diagnostic.SystemInformation,
 	rawInfo string,
@@ -104,7 +122,8 @@ func TestSystemHandler(t *testing.T) {
 	for _, tCase := range tests {
 		t.Run(tCase.name, func(t *testing.T) {
 			t.Parallel()
-			handler := diagnostic.NewDiagnosticHandler(&log, 0, &SystemCollectorMock{}, uuid.New(), uuid.New(), nil)
+
+			handler := diagnostic.NewDiagnosticHandler(&log, 0, &SystemCollectorMock{}, uuid.New(), uuid.New(), nil, nil, nil)
 			recorder := httptest.NewRecorder()
 			ctx := setCtxValuesForSystemCollector(tCase.systemInfo, tCase.rawInfo, tCase.err)
 			request, err := http.NewRequestWithContext(ctx, http.MethodGet, "/diag/syste,", nil)
@@ -162,7 +181,7 @@ func TestTunnelStateHandler(t *testing.T) {
 		t.Run(tCase.name, func(t *testing.T) {
 			t.Parallel()
 			tracker := newTrackerFromConns(t, tCase.connections)
-			handler := diagnostic.NewDiagnosticHandler(&log, 0, nil, tCase.tunnelID, tCase.clientID, tracker)
+			handler := diagnostic.NewDiagnosticHandler(&log, 0, nil, tCase.tunnelID, tCase.clientID, tracker, nil, nil)
 			recorder := httptest.NewRecorder()
 			handler.TunnelStateHandler(recorder, nil)
 			decoder := json.NewDecoder(recorder.Body)
@@ -182,3 +201,59 @@ func TestTunnelStateHandler(t *testing.T) {
 		})
 	}
 }
+
+func TestConfigurationHandler(t *testing.T) {
+	t.Parallel()
+
+	log := zerolog.Nop()
+
+	tests := []struct {
+		name     string
+		flags    map[string]string
+		expected map[string]string
+	}{
+		{
+			name:  "empty cli",
+			flags: make(map[string]string),
+			expected: map[string]string{
+				"uid": "0",
+			},
+		},
+		{
+			name: "cli with flags",
+			flags: map[string]string{
+				"a": "a",
+				"b": "a",
+				"c": "a",
+				"d": "a",
+			},
+			expected: map[string]string{
+				"b":   "a",
+				"c":   "a",
+				"d":   "a",
+				"uid": "0",
+			},
+		},
+	}
+
+	for _, tCase := range tests {
+		t.Run(tCase.name, func(t *testing.T) {
+			var response map[string]string
+
+			t.Parallel()
+			ctx := buildCliContext(t, tCase.flags)
+			handler := diagnostic.NewDiagnosticHandler(&log, 0, nil, uuid.New(), uuid.New(), nil, ctx, []string{"b", "c", "d"})
+			recorder := httptest.NewRecorder()
+			handler.ConfigurationHandler(recorder, nil)
+			decoder := json.NewDecoder(recorder.Body)
+			err := decoder.Decode(&response)
+			require.NoError(t, err)
+			_, ok := response["uid"]
+			assert.True(t, ok)
+			delete(tCase.expected, "uid")
+			delete(response, "uid")
+			assert.Equal(t, http.StatusOK, recorder.Code)
+			assert.Equal(t, tCase.expected, response)
+		})
+	}
+}

logger/configuration.go

@@ -76,10 +76,10 @@ func CreateConfig(
 
 	var file *FileConfig
 	var rolling *RollingConfig
-	if rollingLogPath != "" {
+	if nonRollingLogFilePath != "" {
-		rolling = createRollingConfig(rollingLogPath)
-	} else if nonRollingLogFilePath != "" {
 		file = createFileConfig(nonRollingLogFilePath)
+	} else if rollingLogPath != "" {
+		rolling = createRollingConfig(rollingLogPath)
 	}
 
 	if minLevel == "" {

metrics/metrics.go

@@ -94,6 +94,7 @@ func newMetricsHandler(
 		})
 	}
 
+	router.HandleFunc("/diag/configuration", config.DiagnosticHandler.ConfigurationHandler)
 	router.HandleFunc("/diag/tunnel", config.DiagnosticHandler.TunnelStateHandler)
 	router.HandleFunc("/diag/system", config.DiagnosticHandler.SystemHandler)