func gcpHealthcheck()

in http.go [33:64]
21 lines of code
6 McCabe index (conditional complexity)

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)
	})
}