services/horizon/internal: Add flag to disable path finding endpoints

services/horizon/internal/app.go

@@ -90,7 +90,9 @@ func (a *App) Serve() error {
 	}
 
 	go a.run()
-	go a.orderBookStream.Run(a.ctx)
+	if !a.config.DisablePathFinding {
+		go a.orderBookStream.Run(a.ctx)
+	}
 
 	// WaitGroup for all go routines. Makes sure that DB is closed when
 	// all services gracefully shutdown.

services/horizon/internal/config.go

@@ -52,6 +52,8 @@ type Config struct {
 	// DisablePoolPathFinding configures horizon to run path finding without including liquidity pools
 	// in the path finding search.
 	DisablePoolPathFinding bool
+	// DisablePathFinding configures horizon without the path finding endpoint.
+	DisablePathFinding bool
 	// MaxPathFindingRequests is the maximum number of path finding requests horizon will allow
 	// in a 1-second period. A value of 0 disables the limit.
 	MaxPathFindingRequests uint

services/horizon/internal/flags.go

@@ -392,6 +392,14 @@ func Flags() (*Config, support.ConfigOptions) {
 			Required:    false,
 			Usage:       "excludes liquidity pools from consideration in the `/paths` endpoint",
 		},
+		&support.ConfigOption{
+			Name:        "disable-path-finding",
+			ConfigKey:   &config.DisablePathFinding,
+			OptType:     types.Bool,
+			FlagDefault: false,
+			Required:    false,
+			Usage:       "disables the path finding endpoints",
+		},
 		&support.ConfigOption{
 			Name:        "max-path-finding-requests",
 			ConfigKey:   &config.MaxPathFindingRequests,

services/horizon/internal/httpx/router.go

@@ -196,22 +196,24 @@ func (r *Router) addRoutes(config *RouterConfig, rateLimiter *throttled.HTTPRate
 
 		r.With(stateMiddleware.Wrap).Method(http.MethodGet, "/assets", restPageHandler(ledgerState, actions.AssetStatsHandler{LedgerState: ledgerState}))
 
-		findPaths := ObjectActionHandler{actions.FindPathsHandler{
-			StaleThreshold:       config.StaleThreshold,
-			SetLastLedgerHeader:  true,
-			MaxPathLength:        config.MaxPathLength,
-			MaxAssetsParamLength: config.MaxAssetsPerPathRequest,
-			PathFinder:           config.PathFinder,
-		}}
-		findFixedPaths := ObjectActionHandler{actions.FindFixedPathsHandler{
-			MaxPathLength:        config.MaxPathLength,
-			SetLastLedgerHeader:  true,
-			MaxAssetsParamLength: config.MaxAssetsPerPathRequest,
-			PathFinder:           config.PathFinder,
-		}}
-		r.With(stateMiddleware.Wrap).Method(http.MethodGet, "/paths", findPaths)
-		r.With(stateMiddleware.Wrap).Method(http.MethodGet, "/paths/strict-receive", findPaths)
-		r.With(stateMiddleware.Wrap).Method(http.MethodGet, "/paths/strict-send", findFixedPaths)
+		if config.PathFinder != nil {
+			findPaths := ObjectActionHandler{actions.FindPathsHandler{
+				StaleThreshold:       config.StaleThreshold,
+				SetLastLedgerHeader:  true,
+				MaxPathLength:        config.MaxPathLength,
+				MaxAssetsParamLength: config.MaxAssetsPerPathRequest,
+				PathFinder:           config.PathFinder,
+			}}
+			findFixedPaths := ObjectActionHandler{actions.FindFixedPathsHandler{
+				MaxPathLength:        config.MaxPathLength,
+				SetLastLedgerHeader:  true,
+				MaxAssetsParamLength: config.MaxAssetsPerPathRequest,
+				PathFinder:           config.PathFinder,
+			}}
+			r.With(stateMiddleware.Wrap).Method(http.MethodGet, "/paths", findPaths)
+			r.With(stateMiddleware.Wrap).Method(http.MethodGet, "/paths/strict-receive", findPaths)
+			r.With(stateMiddleware.Wrap).Method(http.MethodGet, "/paths/strict-send", findFixedPaths)
+		}
 		r.With(stateMiddleware.Wrap).Method(
 			http.MethodGet,
 			"/order_book",

services/horizon/internal/init.go

@@ -126,6 +126,9 @@ func initIngester(app *App) {
 }
 
 func initPathFinder(app *App) {
+	if app.config.DisablePathFinding {
+		return
+	}
 	orderBookGraph := orderbook.NewOrderBookGraph()
 	app.orderBookStream = ingest.NewOrderBookStream(
 		&history.Q{app.HorizonSession()},
@@ -192,7 +195,9 @@ func initDbMetrics(app *App) {
 
 	app.coreState.RegisterMetrics(app.prometheusRegistry)
 
-	app.prometheusRegistry.MustRegister(app.orderBookStream.LatestLedgerGauge)
+	if !app.config.DisablePathFinding {
+		app.prometheusRegistry.MustRegister(app.orderBookStream.LatestLedgerGauge)
+	}
 }
 
 // initGoMetrics registers the Go collector provided by prometheus package which

services/horizon/internal/integration/parameters_test.go

@@ -190,6 +190,27 @@ func TestMaxPathFindingRequests(t *testing.T) {
 	})
 }
 
+func TestDisablePathFinding(t *testing.T) {
+	t.Run("default", func(t *testing.T) {
+		test := NewParameterTest(t, map[string]string{})
+		err := test.StartHorizon()
+		assert.NoError(t, err)
+		test.WaitForHorizon()
+		assert.Equal(t, test.Horizon().Config().MaxPathFindingRequests, uint(0))
+		_, ok := test.Horizon().Paths().(simplepath.InMemoryFinder)
+		assert.True(t, ok)
+		test.Shutdown()
+	})
+	t.Run("set to true", func(t *testing.T) {
+		test := NewParameterTest(t, map[string]string{"disable-path-finding": "true"})
+		err := test.StartHorizon()
+		assert.NoError(t, err)
+		test.WaitForHorizon()
+		assert.Nil(t, test.Horizon().Paths())
+		test.Shutdown()
+	})
+}
+
 // Pattern taken from testify issue:
 // https://github.com/stretchr/testify/issues/858#issuecomment-600491003
 //