Integrate HealthCheck middleware

http.go

@@ -9,6 +9,7 @@ import (
 	"strings"
 	"time"
 
+	"github.com/justinas/alice"
 	"github.com/oauth2-proxy/oauth2-proxy/pkg/apis/options"
 	"github.com/oauth2-proxy/oauth2-proxy/pkg/logger"
 )
@@ -29,45 +30,6 @@ func (s *Server) ListenAndServe() {
 	}
 }
 
-// Used with gcpHealthcheck()
-const userAgentHeader = "User-Agent"
-const googleHealthCheckUserAgent = "GoogleHC/1.0"
-const rootPath = "/"
-
-// gcpHealthcheck handles healthcheck queries from GCP.
-func gcpHealthcheck(h http.Handler) http.Handler {
-	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-		// Check for liveness and readiness:  used for Google App Engine
-		if r.URL.EscapedPath() == "/liveness_check" {
-			w.WriteHeader(http.StatusOK)
-			w.Write([]byte("OK"))
-			return
-		}
-		if r.URL.EscapedPath() == "/readiness_check" {
-			w.WriteHeader(http.StatusOK)
-			w.Write([]byte("OK"))
-			return
-		}
-
-		// Check for GKE ingress healthcheck:  The ingress requires the root
-		// path of the target to return a 200 (OK) to indicate the service's good health. This can be quite a challenging demand
-		// depending on the application's path structure. This middleware filters out the requests from the health check by
-		//
-		// 1. checking that the request path is indeed the root path
-		// 2. ensuring that the User-Agent is "GoogleHC/1.0", the health checker
-		// 3. ensuring the request method is "GET"
-		if r.URL.Path == rootPath &&
-			r.Header.Get(userAgentHeader) == googleHealthCheckUserAgent &&
-			r.Method == http.MethodGet {
-
-			w.WriteHeader(http.StatusOK)
-			return
-		}
-
-		h.ServeHTTP(w, r)
-	})
-}
-
 // ServeHTTP constructs a net.Listener and starts handling HTTP requests
 func (s *Server) ServeHTTP() {
 	HTTPAddress := s.Opts.HTTPAddress
@@ -168,6 +130,12 @@ func (ln tcpKeepAliveListener) Accept() (c net.Conn, err error) {
 	return tc, nil
 }
 
+func newRedirectToHTTPS(opts *options.Options) alice.Constructor {
+	return func(next http.Handler) http.Handler {
+		return redirectToHTTPS(opts, next)
+	}
+}
+
 func redirectToHTTPS(opts *options.Options, h http.Handler) http.Handler {
 	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		proto := r.Header.Get("X-Forwarded-Proto")