Move code to pkg

pkg/middlewares/auth/forward.go

@@ -0,0 +1,213 @@
+package auth
+
+import (
+	"context"
+	"crypto/tls"
+	"fmt"
+	"io/ioutil"
+	"net"
+	"net/http"
+	"strings"
+
+	"github.com/containous/traefik/pkg/config"
+	"github.com/containous/traefik/pkg/middlewares"
+	"github.com/containous/traefik/pkg/tracing"
+	"github.com/opentracing/opentracing-go/ext"
+	"github.com/vulcand/oxy/forward"
+	"github.com/vulcand/oxy/utils"
+)
+
+const (
+	xForwardedURI     = "X-Forwarded-Uri"
+	xForwardedMethod  = "X-Forwarded-Method"
+	forwardedTypeName = "ForwardedAuthType"
+)
+
+type forwardAuth struct {
+	address             string
+	authResponseHeaders []string
+	next                http.Handler
+	name                string
+	tlsConfig           *tls.Config
+	trustForwardHeader  bool
+}
+
+// NewForward creates a forward auth middleware.
+func NewForward(ctx context.Context, next http.Handler, config config.ForwardAuth, name string) (http.Handler, error) {
+	middlewares.GetLogger(ctx, name, forwardedTypeName).Debug("Creating middleware")
+
+	fa := &forwardAuth{
+		address:             config.Address,
+		authResponseHeaders: config.AuthResponseHeaders,
+		next:                next,
+		name:                name,
+		trustForwardHeader:  config.TrustForwardHeader,
+	}
+
+	if config.TLS != nil {
+		tlsConfig, err := config.TLS.CreateTLSConfig()
+		if err != nil {
+			return nil, err
+		}
+
+		fa.tlsConfig = tlsConfig
+	}
+
+	return fa, nil
+}
+
+func (fa *forwardAuth) GetTracingInformation() (string, ext.SpanKindEnum) {
+	return fa.name, ext.SpanKindRPCClientEnum
+}
+
+func (fa *forwardAuth) ServeHTTP(rw http.ResponseWriter, req *http.Request) {
+	logger := middlewares.GetLogger(req.Context(), fa.name, forwardedTypeName)
+
+	// Ensure our request client does not follow redirects
+	httpClient := http.Client{
+		CheckRedirect: func(r *http.Request, via []*http.Request) error {
+			return http.ErrUseLastResponse
+		},
+	}
+
+	if fa.tlsConfig != nil {
+		httpClient.Transport = &http.Transport{
+			TLSClientConfig: fa.tlsConfig,
+		}
+	}
+
+	forwardReq, err := http.NewRequest(http.MethodGet, fa.address, nil)
+	tracing.LogRequest(tracing.GetSpan(req), forwardReq)
+	if err != nil {
+		logMessage := fmt.Sprintf("Error calling %s. Cause %s", fa.address, err)
+		logger.Debug(logMessage)
+		tracing.SetErrorWithEvent(req, logMessage)
+
+		rw.WriteHeader(http.StatusInternalServerError)
+		return
+	}
+
+	writeHeader(req, forwardReq, fa.trustForwardHeader)
+
+	tracing.InjectRequestHeaders(forwardReq)
+
+	forwardResponse, forwardErr := httpClient.Do(forwardReq)
+	if forwardErr != nil {
+		logMessage := fmt.Sprintf("Error calling %s. Cause: %s", fa.address, forwardErr)
+		logger.Debug(logMessage)
+		tracing.SetErrorWithEvent(req, logMessage)
+
+		rw.WriteHeader(http.StatusInternalServerError)
+		return
+	}
+
+	body, readError := ioutil.ReadAll(forwardResponse.Body)
+	if readError != nil {
+		logMessage := fmt.Sprintf("Error reading body %s. Cause: %s", fa.address, readError)
+		logger.Debug(logMessage)
+		tracing.SetErrorWithEvent(req, logMessage)
+
+		rw.WriteHeader(http.StatusInternalServerError)
+		return
+	}
+	defer forwardResponse.Body.Close()
+
+	// Pass the forward response's body and selected headers if it
+	// didn't return a response within the range of [200, 300).
+	if forwardResponse.StatusCode < http.StatusOK || forwardResponse.StatusCode >= http.StatusMultipleChoices {
+		logger.Debugf("Remote error %s. StatusCode: %d", fa.address, forwardResponse.StatusCode)
+
+		utils.CopyHeaders(rw.Header(), forwardResponse.Header)
+		utils.RemoveHeaders(rw.Header(), forward.HopHeaders...)
+
+		// Grab the location header, if any.
+		redirectURL, err := forwardResponse.Location()
+
+		if err != nil {
+			if err != http.ErrNoLocation {
+				logMessage := fmt.Sprintf("Error reading response location header %s. Cause: %s", fa.address, err)
+				logger.Debug(logMessage)
+				tracing.SetErrorWithEvent(req, logMessage)
+
+				rw.WriteHeader(http.StatusInternalServerError)
+				return
+			}
+		} else if redirectURL.String() != "" {
+			// Set the location in our response if one was sent back.
+			rw.Header().Set("Location", redirectURL.String())
+		}
+
+		tracing.LogResponseCode(tracing.GetSpan(req), forwardResponse.StatusCode)
+		rw.WriteHeader(forwardResponse.StatusCode)
+
+		if _, err = rw.Write(body); err != nil {
+			logger.Error(err)
+		}
+		return
+	}
+
+	for _, headerName := range fa.authResponseHeaders {
+		req.Header.Set(headerName, forwardResponse.Header.Get(headerName))
+	}
+
+	req.RequestURI = req.URL.RequestURI()
+	fa.next.ServeHTTP(rw, req)
+}
+
+func writeHeader(req *http.Request, forwardReq *http.Request, trustForwardHeader bool) {
+	utils.CopyHeaders(forwardReq.Header, req.Header)
+	utils.RemoveHeaders(forwardReq.Header, forward.HopHeaders...)
+
+	if clientIP, _, err := net.SplitHostPort(req.RemoteAddr); err == nil {
+		if trustForwardHeader {
+			if prior, ok := req.Header[forward.XForwardedFor]; ok {
+				clientIP = strings.Join(prior, ", ") + ", " + clientIP
+			}
+		}
+		forwardReq.Header.Set(forward.XForwardedFor, clientIP)
+	}
+
+	xMethod := req.Header.Get(xForwardedMethod)
+	switch {
+	case xMethod != "" && trustForwardHeader:
+		forwardReq.Header.Set(xForwardedMethod, xMethod)
+	case req.Method != "":
+		forwardReq.Header.Set(xForwardedMethod, req.Method)
+	default:
+		forwardReq.Header.Del(xForwardedMethod)
+	}
+
+	xfp := req.Header.Get(forward.XForwardedProto)
+	switch {
+	case xfp != "" && trustForwardHeader:
+		forwardReq.Header.Set(forward.XForwardedProto, xfp)
+	case req.TLS != nil:
+		forwardReq.Header.Set(forward.XForwardedProto, "https")
+	default:
+		forwardReq.Header.Set(forward.XForwardedProto, "http")
+	}
+
+	if xfp := req.Header.Get(forward.XForwardedPort); xfp != "" && trustForwardHeader {
+		forwardReq.Header.Set(forward.XForwardedPort, xfp)
+	}
+
+	xfh := req.Header.Get(forward.XForwardedHost)
+	switch {
+	case xfh != "" && trustForwardHeader:
+		forwardReq.Header.Set(forward.XForwardedHost, xfh)
+	case req.Host != "":
+		forwardReq.Header.Set(forward.XForwardedHost, req.Host)
+	default:
+		forwardReq.Header.Del(forward.XForwardedHost)
+	}
+
+	xfURI := req.Header.Get(xForwardedURI)
+	switch {
+	case xfURI != "" && trustForwardHeader:
+		forwardReq.Header.Set(xForwardedURI, xfURI)
+	case req.URL.RequestURI() != "":
+		forwardReq.Header.Set(xForwardedURI, req.URL.RequestURI())
+	default:
+		forwardReq.Header.Del(xForwardedURI)
+	}
+}