cloudflared/vendor/github.com/caddyserver/caddy/rlimit_posix.go

// Copyright 2015 Light Code Labs, LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

// +build !windows,!plan9,!nacl,!js

package caddy

import (
	"fmt"
	"syscall"
)

// checkFdlimit issues a warning if the OS limit for
// max file descriptors is below a recommended minimum.
func checkFdlimit() {
	const min = 8192

	// Warn if ulimit is too low for production sites
	rlimit := &syscall.Rlimit{}
	err := syscall.Getrlimit(syscall.RLIMIT_NOFILE, rlimit)
	if err == nil && rlimit.Cur < min {
		fmt.Printf("WARNING: File descriptor limit %d is too low for production servers. "+
			"At least %d is recommended. Fix with `ulimit -n %d`.\n", rlimit.Cur, min, min)
	}

}