refactoring and restructuring the core proxying machinery (#27)

http/http.go

@@ -30,7 +30,7 @@ func New(cfg *Config) (*httpProxy, error) {
 		return nil, errors.Wrap(err, "error listening")
 	}
 
-	proxy, err := util.NewProxy(cfg.EndpointAddress)
+	proxy, err := NewProxy(cfg.EndpointAddress)
 	if err != nil {
 		return nil, err
 	}

http/proxy.go

@@ -0,0 +1,28 @@
+package http
+
+import (
+	"github.com/sirupsen/logrus"
+	"net/http"
+	"net/http/httputil"
+	"net/url"
+)
+
+func NewProxy(target string) (*httputil.ReverseProxy, error) {
+	targetURL, err := url.Parse(target)
+	if err != nil {
+		return nil, err
+	}
+
+	proxy := httputil.NewSingleHostReverseProxy(targetURL)
+	director := proxy.Director
+	proxy.Director = func(req *http.Request) {
+		director(req)
+		logrus.Debugf("-> %v", req.URL.String())
+		req.Header.Set("X-Proxy", "zrok")
+	}
+	proxy.ErrorHandler = func(w http.ResponseWriter, r *http.Request, err error) {
+		logrus.Errorf("error proxying: %v", err)
+	}
+
+	return proxy, nil
+}

proxy/proxy.go

@@ -20,7 +20,7 @@ func Run(cfg *Config) error {
 	zTransport := http.DefaultTransport.(*http.Transport).Clone()
 	zTransport.DialContext = zDialCtx.Dial
 
-	proxy, err := util.NewServiceProxy(&resolver{})
+	proxy, err := NewServiceProxy(&resolver{})
 	if err != nil {
 		return err
 	}

proxy/service.go

@@ -0,0 +1,89 @@
+package proxy
+
+import (
+	"fmt"
+	"github.com/sirupsen/logrus"
+	"net/http"
+	"net/http/httputil"
+	"net/url"
+	"strings"
+)
+
+type ProxyServiceResolver interface {
+	Service(host string) string
+}
+
+func NewServiceProxy(p ProxyServiceResolver) (*httputil.ReverseProxy, error) {
+	proxy := hostTargetReverseProxy(p)
+	director := proxy.Director
+	proxy.Director = func(req *http.Request) {
+		director(req)
+		logrus.Debugf("-> %v", req.URL.String())
+		req.Header.Set("X-Proxy", "zrok")
+	}
+	proxy.ModifyResponse = func(resp *http.Response) error {
+		return nil
+	}
+	proxy.ErrorHandler = func(w http.ResponseWriter, r *http.Request, err error) {
+		logrus.Errorf("error proxying: %v", err)
+	}
+
+	return proxy, nil
+}
+
+func hostTargetReverseProxy(r ProxyServiceResolver) *httputil.ReverseProxy {
+	director := func(req *http.Request) {
+		targetSvc := r.Service(req.Host)
+		if target, err := url.Parse(fmt.Sprintf("http://%v", targetSvc)); err == nil {
+			targetQuery := target.RawQuery
+			req.URL.Scheme = target.Scheme
+			req.URL.Host = target.Host
+			req.URL.Path, req.URL.RawPath = joinURLPath(target, req.URL)
+			if targetQuery == "" || req.URL.RawQuery == "" {
+				req.URL.RawQuery = targetQuery + req.URL.RawQuery
+			} else {
+				req.URL.RawQuery = targetQuery + "&" + req.URL.RawQuery
+			}
+			if _, ok := req.Header["User-Agent"]; !ok {
+				// explicitly disable User-Agent so it's not set to default value
+				req.Header.Set("User-Agent", "")
+			}
+		} else {
+			logrus.Errorf("error proxying: %v", err)
+		}
+	}
+	return &httputil.ReverseProxy{Director: director}
+}
+
+func joinURLPath(a, b *url.URL) (path, rawpath string) {
+	if a.RawPath == "" && b.RawPath == "" {
+		return singleJoiningSlash(a.Path, b.Path), ""
+	}
+	// Same as singleJoiningSlash, but uses EscapedPath to determine
+	// whether a slash should be added
+	apath := a.EscapedPath()
+	bpath := b.EscapedPath()
+
+	aslash := strings.HasSuffix(apath, "/")
+	bslash := strings.HasPrefix(bpath, "/")
+
+	switch {
+	case aslash && bslash:
+		return a.Path + b.Path[1:], apath + bpath[1:]
+	case !aslash && !bslash:
+		return a.Path + "/" + b.Path, apath + "/" + bpath
+	}
+	return a.Path + b.Path, apath + bpath
+}
+
+func singleJoiningSlash(a, b string) string {
+	aslash := strings.HasSuffix(a, "/")
+	bslash := strings.HasPrefix(b, "/")
+	switch {
+	case aslash && bslash:
+		return a + b[1:]
+	case !aslash && !bslash:
+		return a + "/" + b
+	}
+	return a + b
+}

util/proxy.go

@@ -1,60 +1,11 @@
 package util
 
 import (
-	"fmt"
-	"github.com/sirupsen/logrus"
 	"net/http"
 	"net/http/httputil"
-	"net/url"
-	"strings"
 	"sync/atomic"
 )
 
-type ProxyServiceResolver interface {
-	Service(host string) string
-}
-
-func NewProxy(target string) (*httputil.ReverseProxy, error) {
-	targetURL, err := url.Parse(target)
-	if err != nil {
-		return nil, err
-	}
-
-	proxy := httputil.NewSingleHostReverseProxy(targetURL)
-	director := proxy.Director
-	proxy.Director = func(req *http.Request) {
-		director(req)
-		logrus.Debugf("-> %v", req.URL.String())
-		req.Header.Set("X-Proxy", "zrok")
-	}
-	proxy.ModifyResponse = func(resp *http.Response) error {
-		return nil
-	}
-	proxy.ErrorHandler = func(w http.ResponseWriter, r *http.Request, err error) {
-		logrus.Errorf("error proxying: %v", err)
-	}
-
-	return proxy, nil
-}
-
-func NewServiceProxy(p ProxyServiceResolver) (*httputil.ReverseProxy, error) {
-	proxy := hostTargetReverseProxy(p)
-	director := proxy.Director
-	proxy.Director = func(req *http.Request) {
-		director(req)
-		logrus.Debugf("-> %v", req.URL.String())
-		req.Header.Set("X-Proxy", "zrok")
-	}
-	proxy.ModifyResponse = func(resp *http.Response) error {
-		return nil
-	}
-	proxy.ErrorHandler = func(w http.ResponseWriter, r *http.Request, err error) {
-		logrus.Errorf("error proxying: %v", err)
-	}
-
-	return proxy, nil
-}
-
 type proxyHandler struct {
 	proxy    *httputil.ReverseProxy
 	requests int32
@@ -79,60 +30,3 @@ func (self *proxyHandler) Requests() int32 {
 func (self *proxyHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 	self.proxy.ServeHTTP(w, r)
 }
-
-func hostTargetReverseProxy(r ProxyServiceResolver) *httputil.ReverseProxy {
-	director := func(req *http.Request) {
-		targetSvc := r.Service(req.Host)
-		if target, err := url.Parse(fmt.Sprintf("http://%v", targetSvc)); err == nil {
-			targetQuery := target.RawQuery
-			req.URL.Scheme = target.Scheme
-			req.URL.Host = target.Host
-			req.URL.Path, req.URL.RawPath = joinURLPath(target, req.URL)
-			if targetQuery == "" || req.URL.RawQuery == "" {
-				req.URL.RawQuery = targetQuery + req.URL.RawQuery
-			} else {
-				req.URL.RawQuery = targetQuery + "&" + req.URL.RawQuery
-			}
-			if _, ok := req.Header["User-Agent"]; !ok {
-				// explicitly disable User-Agent so it's not set to default value
-				req.Header.Set("User-Agent", "")
-			}
-		} else {
-			logrus.Errorf("error proxying: %v", err)
-		}
-	}
-	return &httputil.ReverseProxy{Director: director}
-}
-
-func joinURLPath(a, b *url.URL) (path, rawpath string) {
-	if a.RawPath == "" && b.RawPath == "" {
-		return singleJoiningSlash(a.Path, b.Path), ""
-	}
-	// Same as singleJoiningSlash, but uses EscapedPath to determine
-	// whether a slash should be added
-	apath := a.EscapedPath()
-	bpath := b.EscapedPath()
-
-	aslash := strings.HasSuffix(apath, "/")
-	bslash := strings.HasPrefix(bpath, "/")
-
-	switch {
-	case aslash && bslash:
-		return a.Path + b.Path[1:], apath + bpath[1:]
-	case !aslash && !bslash:
-		return a.Path + "/" + b.Path, apath + "/" + bpath
-	}
-	return a.Path + b.Path, apath + bpath
-}
-
-func singleJoiningSlash(a, b string) string {
-	aslash := strings.HasSuffix(a, "/")
-	bslash := strings.HasPrefix(b, "/")
-	switch {
-	case aslash && bslash:
-		return a + b[1:]
-	case !aslash && !bslash:
-		return a + "/" + b
-	}
-	return a + b
-}