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

diagnostic/consts.go

@@ -3,8 +3,10 @@ package diagnostic
 import "time"
 
 const (
-	defaultCollectorTimeout  = time.Second * 10 // This const define the timeout value of a collector operation.
-	collectorField           = "collector"      // used for logging purposes
-	systemCollectorName      = "system"         // used for logging purposes
-	tunnelStateCollectorName = "tunnelState"    // used for logging purposes
+	defaultCollectorTimeout    = time.Second * 10 // This const define the timeout value of a collector operation.
+	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

@@ -4,21 +4,28 @@ 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"
 )
 
 type Handler struct {
-	log             *zerolog.Logger
-	timeout         time.Duration
-	systemCollector SystemCollector
-	tunnelID        uuid.UUID
-	connectorID     uuid.UUID
-	tracker         *tunnelstate.ConnTracker
+	log               *zerolog.Logger
+	timeout           time.Duration
+	systemCollector   SystemCollector
+	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 {
@@ -35,12 +44,14 @@ func NewDiagnosticHandler(
 	}
 
 	return &Handler{
-		log:             &logger,
-		timeout:         timeout,
-		systemCollector: systemCollector,
-		tunnelID:        tunnelID,
-		connectorID:     connectorID,
-		tracker:         tracker,
+		log:               &logger,
+		timeout:           timeout,
+		systemCollector:   systemCollector,
+		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) {
-	bytesWritten, err := writer.Write(bytes)
+func (handler *Handler) ConfigurationHandler(writer http.ResponseWriter, _ *http.Request) {
+	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)
+		})
+	}
+}