services/horizon: Return 503 error in POST /transactions if Stellar-C…

…ore not synced

services/horizon/internal/actions/helpers.go

@@ -345,6 +345,10 @@ func getAsset(r *http.Request, prefix string) (xdr.Asset, error) {
 func getURLParam(r *http.Request, key string) (string, bool) {
 	rctx := chi.RouteContext(r.Context())
 
+	if rctx == nil {
+		return "", false
+	}
+
 	// Return immediately if keys does not match Values
 	// This can happen when a named param is not specified.
 	// This is a bug in chi: https://github.com/go-chi/chi/issues/426

services/horizon/internal/actions/root.go

@@ -5,24 +5,18 @@ import (
 	"net/url"
 
 	"github.com/stellar/go/protocols/horizon"
+	"github.com/stellar/go/services/horizon/internal/corestate"
 	"github.com/stellar/go/services/horizon/internal/ledger"
 	"github.com/stellar/go/services/horizon/internal/resourceadapter"
 )
 
-type CoreSettings struct {
-	Synced                       bool
-	CurrentProtocolVersion       int32
-	CoreSupportedProtocolVersion int32
-	CoreVersion                  string
-}
-
-type CoreSettingsGetter interface {
-	GetCoreSettings() CoreSettings
+type CoreStateGetter interface {
+	GetCoreState() corestate.State
 }
 
 type GetRootHandler struct {
 	LedgerState *ledger.State
-	CoreSettingsGetter
+	CoreStateGetter
 	NetworkPassphrase string
 	FriendbotURL      *url.URL
 	HorizonVersion    string
@@ -37,16 +31,16 @@ func (handler GetRootHandler) GetResource(w HeaderWriter, r *http.Request) (inte
 		"strictReceivePaths": StrictReceivePathsQuery{}.URITemplate(),
 		"strictSendPaths":    FindFixedPathsQuery{}.URITemplate(),
 	}
-	coreSettings := handler.GetCoreSettings()
+	coreState := handler.GetCoreState()
 	resourceadapter.PopulateRoot(
 		r.Context(),
 		&res,
 		handler.LedgerState.CurrentStatus(),
 		handler.HorizonVersion,
-		coreSettings.CoreVersion,
+		coreState.CoreVersion,
 		handler.NetworkPassphrase,
-		coreSettings.CurrentProtocolVersion,
-		coreSettings.CoreSupportedProtocolVersion,
+		coreState.CurrentProtocolVersion,
+		coreState.CoreSupportedProtocolVersion,
 		handler.FriendbotURL,
 		templates,
 	)

services/horizon/internal/actions/submit_transaction.go

@@ -19,6 +19,7 @@ import (
 type SubmitTransactionHandler struct {
 	Submitter         *txsub.System
 	NetworkPassphrase string
+	CoreStateGetter
 }
 
 type envelopeInfo struct {
@@ -136,6 +137,11 @@ func (handler SubmitTransactionHandler) GetResource(w HeaderWriter, r *http.Requ
 		}
 	}
 
+	coreState := handler.GetCoreState()
+	if !coreState.Synced {
+		return nil, hProblem.StaleHistory
+	}
+
 	submission := handler.Submitter.Submit(
 		r.Context(),
 		info.raw,

services/horizon/internal/app.go

@@ -13,8 +13,7 @@ import (
 	"github.com/prometheus/client_golang/prometheus"
 
 	"github.com/stellar/go/clients/stellarcore"
-	proto "github.com/stellar/go/protocols/stellarcore"
-	"github.com/stellar/go/services/horizon/internal/actions"
+	"github.com/stellar/go/services/horizon/internal/corestate"
 	"github.com/stellar/go/services/horizon/internal/db2/history"
 	"github.com/stellar/go/services/horizon/internal/httpx"
 	"github.com/stellar/go/services/horizon/internal/ingest"
@@ -30,26 +29,6 @@ import (
 	"github.com/stellar/go/support/log"
 )
 
-type coreSettingsStore struct {
-	sync.RWMutex
-	actions.CoreSettings
-}
-
-func (c *coreSettingsStore) set(resp *proto.InfoResponse) {
-	c.Lock()
-	defer c.Unlock()
-	c.Synced = resp.IsSynced()
-	c.CoreVersion = resp.Info.Build
-	c.CurrentProtocolVersion = int32(resp.Info.Ledger.Version)
-	c.CoreSupportedProtocolVersion = int32(resp.Info.ProtocolVersion)
-}
-
-func (c *coreSettingsStore) get() actions.CoreSettings {
-	c.RLock()
-	defer c.RUnlock()
-	return c.CoreSettings
-}
-
 // App represents the root of the state of a horizon instance.
 type App struct {
 	done            chan struct{}
@@ -60,7 +39,7 @@ type App struct {
 	ctx             context.Context
 	cancel          func()
 	horizonVersion  string
-	coreSettings    coreSettingsStore
+	coreState       corestate.Store
 	orderBookStream *ingest.OrderBookStream
 	submitter       *txsub.System
 	paths           paths.Finder
@@ -80,8 +59,8 @@ type App struct {
 	coreSynced                        prometheus.GaugeFunc
 }
 
-func (a *App) GetCoreSettings() actions.CoreSettings {
-	return a.coreSettings.get()
+func (a *App) GetCoreState() corestate.State {
+	return a.coreState.Get()
 }
 
 const tickerMaxFrequency = 1 * time.Second
@@ -390,7 +369,7 @@ func (a *App) UpdateStellarCoreInfo(ctx context.Context) {
 		os.Exit(1)
 	}
 
-	a.coreSettings.set(resp)
+	a.coreState.Set(resp)
 }
 
 // DeleteUnretainedHistory forwards to the app's reaper.  See

services/horizon/internal/httpx/router.go

@@ -43,7 +43,7 @@ type RouterConfig struct {
 	MaxPathLength         uint
 	PathFinder            paths.Finder
 	PrometheusRegistry    *prometheus.Registry
-	CoreGetter            actions.CoreSettingsGetter
+	CoreGetter            actions.CoreStateGetter
 	HorizonVersion        string
 	FriendbotURL          *url.URL
 	HealthCheck           http.Handler
@@ -124,11 +124,11 @@ func (r *Router) addRoutes(config *RouterConfig, rateLimiter *throttled.HTTPRate
 	r.Method(http.MethodGet, "/health", config.HealthCheck)
 
 	r.Method(http.MethodGet, "/", ObjectActionHandler{Action: actions.GetRootHandler{
-		LedgerState:        ledgerState,
-		CoreSettingsGetter: config.CoreGetter,
-		NetworkPassphrase:  config.NetworkPassphrase,
-		FriendbotURL:       config.FriendbotURL,
-		HorizonVersion:     config.HorizonVersion,
+		LedgerState:       ledgerState,
+		CoreStateGetter:   config.CoreGetter,
+		NetworkPassphrase: config.NetworkPassphrase,
+		FriendbotURL:      config.FriendbotURL,
+		HorizonVersion:    config.HorizonVersion,
 	}})
 
 	streamHandler := sse.StreamHandler{
@@ -292,6 +292,7 @@ func (r *Router) addRoutes(config *RouterConfig, rateLimiter *throttled.HTTPRate
 	r.Method(http.MethodPost, "/transactions", ObjectActionHandler{actions.SubmitTransactionHandler{
 		Submitter:         config.TxSubmitter,
 		NetworkPassphrase: config.NetworkPassphrase,
+		CoreStateGetter:   config.CoreGetter,
 	}})
 
 	// Network state related endpoints

services/horizon/internal/init.go

@@ -208,7 +208,7 @@ func initDbMetrics(app *App) {
 			Help: "determines if Stellar-Core defined by --stellar-core-url is synced with the network",
 		},
 		func() float64 {
-			if app.coreSettings.Synced {
+			if app.coreState.Synced {
 				return 1
 			} else {
 				return 0

services/horizon/internal/render/problem/problem.go

@@ -100,8 +100,8 @@ var (
 		Status: http.StatusServiceUnavailable,
 		Detail: "This horizon instance is configured to reject client requests " +
 			"when it can determine that the history database is lagging too far " +
-			"behind the connected instance of stellar-core or read replica. Please " +
-			"try again later.",
+			"behind the connected instance of Stellar-Core or read replica. It's " +
+			"also possible that Stellar-Core is out of sync. Please try again later.",
 	}
 
 	// StillIngesting is a well-known problem type.  Use it as a shortcut