proxy: implement simple healthcheck

proxy/Dockerfile

@@ -7,6 +7,10 @@ COPY . .
 RUN go build -o /work/proxy .
 
 # Copy binary to alpine
-FROM gcr.io/distroless/base-debian10
+FROM gcr.io/distroless/base-debian10:debug
+
 COPY --from=builder /work/proxy /
+
+HEALTHCHECK CMD [ "wget", "spider", "http://localhost:4180/pbprox/ping" ]
+
 ENTRYPOINT ["/proxy"]

proxy/pkg/server/api.go

@@ -47,7 +47,6 @@ func getCommonOptions() *options.Options {
 	commonOpts.EmailDomains = []string{"*"}
 	commonOpts.ProviderType = "oidc"
 	commonOpts.ProxyPrefix = "/pbprox"
-	commonOpts.PingPath = "/pbprox/ping"
 	commonOpts.SkipProviderButton = true
 	commonOpts.Logging.SilencePing = true
 	commonOpts.SetXAuthRequest = true

proxy/pkg/server/server.go

@@ -82,6 +82,10 @@ func (s *Server) ServeHTTPS() {
 }
 
 func (s *Server) handler(w http.ResponseWriter, r *http.Request) {
+	if r.URL.Path == "/pbprox/ping" {
+		w.WriteHeader(204)
+		return
+	}
 	handler, ok := s.Handlers[r.Host]
 	if !ok {
 		// If we only have one handler, host name switching doesn't matter