added an option to enable GCP healthcheck endpoints

http.go

@@ -24,6 +24,23 @@ func (s *Server) ListenAndServe() {
 	}
 }
 
+// gcpHealthcheck handles healthcheck queries from GCP
+func gcpHealthcheck(h http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		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
+		}
+		h.ServeHTTP(w, r)
+	})
+}
+
 // ServeHTTP constructs a net.Listener and starts handling HTTP requests
 func (s *Server) ServeHTTP() {
 	HTTPAddress := s.Opts.HTTPAddress

main.go

@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"log"
 	"math/rand"
+	"net/http"
 	"os"
 	"runtime"
 	"strings"
@@ -92,6 +93,7 @@ func main() {
 	flagSet.String("acr-values", "http://idmanagement.gov/ns/assurance/loa/1", "acr values string:  optional, used by login.gov")
 	flagSet.String("jwt-key", "", "private key used to sign JWT: required by login.gov")
 	flagSet.String("pubjwk-url", "", "JWK pubkey access endpoint: required by login.gov")
+	flagSet.Bool("gcp-healthchecks", false, "Enable GCP healthcheck endpoints")
 
 	flagSet.Parse(os.Args[1:])
 
@@ -139,8 +141,14 @@ func main() {
 
 	rand.Seed(time.Now().UnixNano())
 
+	var myhandler http.Handler
+	if opts.GCPHealthChecks {
+		myhandler = gcpHealthcheck(LoggingHandler(os.Stdout, oauthproxy, opts.RequestLogging, opts.RequestLoggingFormat))
+	} else {
+		myhandler = LoggingHandler(os.Stdout, oauthproxy, opts.RequestLogging, opts.RequestLoggingFormat)
+	}
 	s := &Server{
-		Handler: LoggingHandler(os.Stdout, oauthproxy, opts.RequestLogging, opts.RequestLoggingFormat),
+		Handler: myhandler,
 		Opts:    opts,
 	}
 	s.ListenAndServe()

options.go

@@ -90,6 +90,7 @@ type Options struct {
 	AcrValues       string `flag:"acr-values" cfg:"acr_values" env:"OAUTH2_PROXY_ACR_VALUES"`
 	JWTKey          string `flag:"jwt-key" cfg:"jwt_key" env:"OAUTH2_PROXY_JWT_KEY"`
 	PubJWKURL       string `flag:"pubjwk-url" cfg:"pubjwk_url" env:"OAUTH2_PROXY_PUBJWK_URL"`
+	GCPHealthChecks bool   `flag:"gcp-healthchecks" cfg:"gcp_healthchecks" env:"OAUTH2_PROXY_GCP_HEALTHCHECKS"`
 
 	// internal values that are set after config validation
 	redirectURL   *url.URL