New /routing/v1/health endpoint for service health monitoring

cmd/routing-api/main.go

@@ -323,6 +323,7 @@ func apiHandler(cfg config.Config, uaaClient uaaclient.TokenValidator, database
 	tcpMappingsHandler := handlers.NewTcpRouteMappingsHandler(uaaClient, validator, database, int(cfg.MaxTTL.Seconds()), logger)
 
 	actions := rata.Handlers{
+		routing_api.CheckHealth:           route(routesHandler.Health),
 		routing_api.UpsertRoute:           route(routesHandler.Upsert),
 		routing_api.DeleteRoute:           route(routesHandler.Delete),
 		routing_api.ListRoute:             route(routesHandler.List),

db/db_sql.go

@@ -23,6 +23,7 @@ import (
 
 //go:generate counterfeiter -o fakes/fake_db.go . DB
 type DB interface {
+	CheckHealth() error
 	ReadRoutes() ([]models.Route, error)
 	SaveRoute(route models.Route) error
 	DeleteRoute(route models.Route) error
@@ -361,6 +362,15 @@ func notImplementedError() error {
 	return fmt.Errorf("function not implemented: %s", fnName)
 }
 
+func (s *SqlDB) CheckHealth() error {
+	var routes []models.Route
+	err := s.Client.First(&routes)
+	if err != nil {
+		return fmt.Errorf("checking health error: %v", err)
+	}
+	return nil
+}
+
 func (s *SqlDB) ReadRoutes() ([]models.Route, error) {
 	var routes []models.Route
 	now := time.Now()

handlers/middleware.go

@@ -12,8 +12,9 @@ func LogWrap(handler http.Handler, logger lager.Logger) http.HandlerFunc {
 
 	return func(w http.ResponseWriter, r *http.Request) {
 		requestLog := logger.Session("request", lager.Data{
-			"method":  r.Method,
-			"request": r.URL.String(),
+			"remoteAddr": r.RemoteAddr,
+			"method":     r.Method,
+			"request":    r.URL.String(),
 		})
 
 		requestLog.Info("serving", lager.Data{"request-headers": filter(r.Header)})

handlers/routes_handler.go

@@ -2,6 +2,7 @@ package handlers
 
 import (
 	"encoding/json"
+	"fmt"
 	"net/http"
 
 	"code.cloudfoundry.org/lager/v3"
@@ -28,11 +29,29 @@ func NewRoutesHandler(uaaClient uaaclient.TokenValidator, maxTTL int, validator
 	}
 }
 
+func (h *RoutesHandler) Health(w http.ResponseWriter, req *http.Request) {
+	log := h.logger.Session("health-check")
+
+	err := h.db.CheckHealth()
+	if err != nil {
+		handleDBCommunicationError(w, err, log)
+		return
+	}
+	w.WriteHeader(http.StatusOK)
+}
+
 func (h *RoutesHandler) List(w http.ResponseWriter, req *http.Request) {
 	log := h.logger.Session("list-routes")
 
-	err := h.uaaClient.ValidateToken(req.Header.Get("Authorization"), RoutingRoutesReadScope)
+	authHeader := req.Header.Get("Authorization")
+	if authHeader == "" {
+		err := fmt.Errorf("authorization header can't be empty (remoteAddr: %s)", req.RemoteAddr)
+		handleUnauthorizedError(w, err, log)
+		return
+	}
+	err := h.uaaClient.ValidateToken(authHeader, RoutingRoutesReadScope)
 	if err != nil {
+		err := fmt.Errorf("%v (remoteAddr: %s)", err, req.RemoteAddr)
 		handleUnauthorizedError(w, err, log)
 		return
 	}

routes.go

@@ -3,6 +3,7 @@ package routing_api
 import "github.com/tedsuo/rata"
 
 const (
+	CheckHealth           = "Health"
 	UpsertRoute           = "UpsertRoute"
 	DeleteRoute           = "Delete"
 	ListRoute             = "List"
@@ -17,7 +18,9 @@ const (
 	EventStreamTcpRoute   = "TcpRouteEventStream"
 )
 
-var RoutesMap = map[string]rata.Route{UpsertRoute: {Path: "/routing/v1/routes", Method: "POST", Name: UpsertRoute},
+var RoutesMap = map[string]rata.Route{
+	CheckHealth:           {Path: "/routing/v1/health", Method: "GET", Name: CheckHealth},
+	UpsertRoute:           {Path: "/routing/v1/routes", Method: "POST", Name: UpsertRoute},
 	DeleteRoute:           {Path: "/routing/v1/routes", Method: "DELETE", Name: DeleteRoute},
 	ListRoute:             {Path: "/routing/v1/routes", Method: "GET", Name: ListRoute},
 	EventStreamRoute:      {Path: "/routing/v1/events", Method: "GET", Name: EventStreamRoute},