// Copyright (c) 2015-2021 MinIO, Inc.

//

// This file is part of MinIO Object Storage stack

//

// This program is free software: you can redistribute it and/or modify

// it under the terms of the GNU Affero General Public License as published by

// the Free Software Foundation, either version 3 of the License, or

// (at your option) any later version.

//

// This program is distributed in the hope that it will be useful

// but WITHOUT ANY WARRANTY; without even the implied warranty of

// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the

// GNU Affero General Public License for more details.

//

// You should have received a copy of the GNU Affero General Public License

// along with this program. If not, see <http://www.gnu.org/licenses/>.

package http

import (

"context"

"crypto/tls"

"errors"

"log"

"net"

"net/http"

"os"

"runtime/pprof"

"sync"

"sync/atomic"

"time"

"github.com/dustin/go-humanize"

)

var (

// GlobalMinIOVersion - is sent in the header to all http targets

GlobalMinIOVersion string

// GlobalDeploymentID - is sent in the header to all http targets

GlobalDeploymentID string

)

const (

serverShutdownPoll = 500 * time.Millisecond

// DefaultShutdownTimeout - default shutdown timeout to gracefully shutdown server.

DefaultShutdownTimeout = 5 * time.Second

// DefaultIdleTimeout for idle inactive connections

DefaultIdleTimeout = 30 * time.Second

// DefaultReadHeaderTimeout for very slow inactive connections

DefaultReadHeaderTimeout = 30 * time.Second

// DefaultMaxHeaderBytes - default maximum HTTP header size in bytes.

DefaultMaxHeaderBytes = 1 * humanize.MiByte

)

// Server - extended http.Server supports multiple addresses to serve and enhanced connection handling.

type Server struct {

http.Server

Addrs []string // addresses on which the server listens for new connection.

ShutdownTimeout time.Duration // timeout used for graceful server shutdown.

listenerMutex sync.Mutex // to guard 'listener' field.

listener *httpListener // HTTP listener for all 'Addrs' field.

inShutdown uint32 // indicates whether the server is in shutdown or not

requestCount int32 // counter holds no. of request in progress.

}

// GetRequestCount - returns number of request in progress.

func (srv *Server) GetRequestCount() int {

return int(atomic.LoadInt32(&srv.requestCount))

}

// Start - start HTTP server

func (srv *Server) Start(ctx context.Context) (err error) {

// Take a copy of server fields.

var tlsConfig *tls.Config

if srv.TLSConfig != nil {

tlsConfig = srv.TLSConfig.Clone()

}

handler := srv.Handler // if srv.Handler holds non-synced state -> possible data race

// Create new HTTP listener.

var listener *httpListener

listener, err = newHTTPListener(

ctx,

srv.Addrs,

)

if err != nil {

return err

}

// Wrap given handler to do additional

// * return 503 (service unavailable) if the server in shutdown.

wrappedHandler := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {

// If server is in shutdown.

if atomic.LoadUint32(&srv.inShutdown) != 0 {

// To indicate disable keep-alives

w.Header().Set("Connection", "close")

w.WriteHeader(http.StatusServiceUnavailable)

w.Write([]byte(http.ErrServerClosed.Error()))

return

}

atomic.AddInt32(&srv.requestCount, 1)

defer atomic.AddInt32(&srv.requestCount, -1)

// Handle request using passed handler.

handler.ServeHTTP(w, r)

})

srv.listenerMutex.Lock()

srv.Handler = wrappedHandler

srv.listener = listener

srv.listenerMutex.Unlock()

// Start servicing with listener.

if tlsConfig != nil {

return srv.Server.Serve(tls.NewListener(listener, tlsConfig))

}

return srv.Server.Serve(listener)

}

// Shutdown - shuts down HTTP server.

func (srv *Server) Shutdown() error {

srv.listenerMutex.Lock()

if srv.listener == nil {

srv.listenerMutex.Unlock()

return http.ErrServerClosed

}

srv.listenerMutex.Unlock()

if atomic.AddUint32(&srv.inShutdown, 1) > 1 {

// shutdown in progress

return http.ErrServerClosed

}

// Close underneath HTTP listener.

srv.listenerMutex.Lock()

err := srv.listener.Close()

srv.listenerMutex.Unlock()

if err != nil {

return err

}

// Wait for opened connection to be closed up to Shutdown timeout.

shutdownTimeout := srv.ShutdownTimeout

shutdownTimer := time.NewTimer(shutdownTimeout)

ticker := time.NewTicker(serverShutdownPoll)

defer ticker.Stop()

for {

select {

case <-shutdownTimer.C:

// Write all running goroutines.

tmp, err := os.CreateTemp("", "minio-goroutines-*.txt")

if err == nil {

_ = pprof.Lookup("goroutine").WriteTo(tmp, 1)

tmp.Close()

return errors.New("timed out. some connections are still active. goroutines written to " + tmp.Name())

}

return errors.New("timed out. some connections are still active")

case <-ticker.C:

if atomic.LoadInt32(&srv.requestCount) <= 0 {

return nil

}

}

}

}

// UseShutdownTimeout configure server shutdown timeout

func (srv *Server) UseShutdownTimeout(d time.Duration) *Server {

srv.ShutdownTimeout = d

return srv

}

// UseIdleTimeout configure idle connection timeout

func (srv *Server) UseIdleTimeout(d time.Duration) *Server {

srv.IdleTimeout = d

return srv

}

// UseReadHeaderTimeout configure read header timeout

func (srv *Server) UseReadHeaderTimeout(d time.Duration) *Server {

srv.ReadHeaderTimeout = d

return srv

}

// UseHandler configure final handler for this HTTP *Server

func (srv *Server) UseHandler(h http.Handler) *Server {

srv.Handler = h

return srv

}

// UseTLSConfig pass configured TLSConfig for this HTTP *Server

func (srv *Server) UseTLSConfig(cfg *tls.Config) *Server {

srv.TLSConfig = cfg

return srv

}

// UseBaseContext use custom base context for this HTTP *Server

func (srv *Server) UseBaseContext(ctx context.Context) *Server {

srv.BaseContext = func(listener net.Listener) context.Context {

return ctx

}

return srv

}

// UseCustomLogger use customized logger for this HTTP *Server

func (srv *Server) UseCustomLogger(l *log.Logger) *Server {

srv.ErrorLog = l

return srv

}

// NewServer - creates new HTTP server using given arguments.

func NewServer(addrs []string) *Server {

httpServer := &Server{

Addrs: addrs,

}

// This is not configurable for now.

httpServer.MaxHeaderBytes = DefaultMaxHeaderBytes

return httpServer

}

// SetMinIOVersion -- MinIO version from the main package is set here

func SetMinIOVersion(version string) {

GlobalMinIOVersion = version

}

// SetDeploymentID -- Deployment Id from the main package is set here

func SetDeploymentID(deploymentID string) {

GlobalDeploymentID = deploymentID

}