Supporting service name which is different then the resource name (#36)

Author: Hedingber

go.mod

@@ -23,7 +23,7 @@ require (
 	github.com/spf13/pflag v1.0.3 // indirect
 	github.com/stretchr/objx v0.2.0 // indirect
 	github.com/stretchr/testify v1.5.1
-	github.com/v3io/scaler-types v1.5.0
+	github.com/v3io/scaler-types v1.6.0
 	go.uber.org/atomic v1.4.0 // indirect
 	go.uber.org/multierr v1.1.0 // indirect
 	golang.org/x/crypto v0.0.0-20191011191535-87dc89f01550 // indirect

go.sum

@@ -63,6 +63,7 @@ github.com/stretchr/testify v1.5.1 h1:nOGnQDM7FYENwehXlg/kFVnos3rEvtKTjRvOWSzb6H
 github.com/stretchr/testify v1.5.1/go.mod h1:5W2xD1RspED5o8YsWQXVCued0rvSQ+mT+I5cxcmMvtA=
 github.com/v3io/scaler-types v1.5.0 h1:3nA56ewksIWmcGPW45wXUBMT3AZ4m61HMInR33j4uvY=
 github.com/v3io/scaler-types v1.5.0/go.mod h1:Q2xufg8/9sLUOHh8/ckhHaAzZy2M8AgEknMTJ5HxvFI=
+github.com/v3io/scaler-types v1.6.0/go.mod h1:Q2xufg8/9sLUOHh8/ckhHaAzZy2M8AgEknMTJ5HxvFI=
 go.uber.org/atomic v1.4.0 h1:cxzIVoETapQEqDhQu3QfnvXAV4AlzcvUCxkVUFw3+EU=
 go.uber.org/atomic v1.4.0/go.mod h1:gD2HeocX3+yG+ygLZcrzQJaqmWj9AIm7n08wl/qW/PE=
 go.uber.org/multierr v1.1.0 h1:HoEmRHQPVSqub6w2z2d2EOVs2fjyFRGyofhKuyDq0QI=

pkg/dlx/dlx.go

@@ -26,6 +26,7 @@ func NewDLX(parentLogger logger.Logger,
 
 	handler, err := NewHandler(childLogger,
 		resourceStarter,
+		resourceScaler,
 		options.TargetNameHeader,
 		options.TargetPathHeader,
 		options.TargetPort)

pkg/dlx/handler.go

@@ -8,25 +8,29 @@ import (
 
 	"github.com/nuclio/errors"
 	"github.com/nuclio/logger"
+	"github.com/v3io/scaler-types"
 )
 
 type Handler struct {
 	logger           logger.Logger
 	HandleFunc       func(http.ResponseWriter, *http.Request)
 	resourceStarter  *ResourceStarter
+	resourceScaler   scaler_types.ResourceScaler
 	targetNameHeader string
 	targetPathHeader string
 	targetPort       int
 }
 
 func NewHandler(parentLogger logger.Logger,
 	resourceStarter *ResourceStarter,
+	resourceScaler scaler_types.ResourceScaler,
 	targetNameHeader string,
 	targetPathHeader string,
 	targetPort int) (Handler, error) {
 	h := Handler{
 		logger:           parentLogger.GetChild("handler"),
 		resourceStarter:  resourceStarter,
+		resourceScaler:   resourceScaler,
 		targetNameHeader: targetNameHeader,
 		targetPathHeader: targetPathHeader,
 		targetPort:       targetPort,
@@ -47,7 +51,7 @@ func (h *Handler) handleRequest(res http.ResponseWriter, req *http.Request) {
 	forwardedHost := req.Header.Get("X-Forwarded-Host")
 	forwardedPort := req.Header.Get("X-Forwarded-Port")
 	originalURI := req.Header.Get("X-Original-Uri")
-	resourceName = req.Header.Get("X-Service-Name")
+	resourceName = req.Header.Get("X-Resource-Name")
 
 	if forwardedHost != "" && forwardedPort != "" && resourceName != "" {
 		targetURL, err = url.Parse(fmt.Sprintf("http://%s:%s/%s", forwardedHost, forwardedPort, originalURI))
@@ -63,7 +67,14 @@ func (h *Handler) handleRequest(res http.ResponseWriter, req *http.Request) {
 			res.WriteHeader(http.StatusBadRequest)
 			return
 		}
-		targetURL, err = url.Parse(fmt.Sprintf("http://%s:%d/%s", resourceName, h.targetPort, path))
+		serviceName, err := h.resourceScaler.ResolveServiceName(scaler_types.Resource{Name: resourceName})
+		if err != nil {
+			h.logger.WarnWith("Failed resolving service name",
+				"err", errors.GetErrorStackString(err, 10))
+			res.WriteHeader(http.StatusInternalServerError)
+			return
+		}
+		targetURL, err = url.Parse(fmt.Sprintf("http://%s:%d/%s", serviceName, h.targetPort, path))
 		if err != nil {
 			res.WriteHeader(h.URLBadParse(resourceName, err))
 			return
@@ -81,6 +92,7 @@ func (h *Handler) handleRequest(res http.ResponseWriter, req *http.Request) {
 		return
 	}
 
+	h.logger.DebugWith("Creating reverse proxy", "targetURL", targetURL)
 	proxy := httputil.NewSingleHostReverseProxy(targetURL)
 	proxy.ServeHTTP(res, req)
 }

pkg/resourcescaler/resourcescaler.go

@@ -21,3 +21,7 @@ func (r *NopResourceScaler) GetResources() ([]scaler_types.Resource, error) {
 func (r *NopResourceScaler) GetConfig() (*scaler_types.ResourceScalerConfig, error) {
 	return nil, nil
 }
+
+func (r *NopResourceScaler) ResolveServiceName(resource scaler_types.Resource) (string, error) {
+	return resource.Name, nil
+}