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package util
import (
"net"
"time"
"github.com/seaweedfs/seaweedfs/weed/glog"
"github.com/seaweedfs/seaweedfs/weed/stats"
)
const (
// minThroughputBytesPerSecond defines the minimum expected throughput (4KB/s)
// Used to calculate timeout scaling based on data transferred
minThroughputBytesPerSecond = 4000
// graceTimeCapMultiplier caps the grace period for slow clients at 3x base timeout
// This prevents indefinite connections while allowing time for server-side chunk fetches
graceTimeCapMultiplier = 3
)
// Listener wraps a net.Listener, and gives a place to store the timeout
// parameters. On Accept, it will wrap the net.Conn with our own Conn for us.
type Listener struct {
net.Listener
ReadTimeout time.Duration
WriteTimeout time.Duration
}
func (l *Listener) Accept() (net.Conn, error) {
c, err := l.Listener.Accept()
if err != nil {
return nil, err
}
stats.ConnectionOpen()
tc := &Conn{
Conn: c,
ReadTimeout: l.ReadTimeout,
WriteTimeout: l.WriteTimeout,
}
return tc, nil
}
// Conn wraps a net.Conn, and sets a deadline for every read
// and write operation.
type Conn struct {
net.Conn
ReadTimeout time.Duration
WriteTimeout time.Duration
isClosed bool
bytesRead int64
bytesWritten int64
lastWrite time.Time
}
// calculateBytesPerTimeout calculates the expected number of bytes that should
// be transferred during one timeout period, based on the minimum throughput.
// Returns at least 1 to prevent division by zero.
func calculateBytesPerTimeout(timeout time.Duration) int64 {
bytesPerTimeout := int64(float64(minThroughputBytesPerSecond) * timeout.Seconds())
if bytesPerTimeout <= 0 {
return 1 // Prevent division by zero
}
return bytesPerTimeout
}
func (c *Conn) Read(b []byte) (count int, e error) {
if c.ReadTimeout != 0 {
// Calculate expected bytes per timeout period based on minimum throughput (4KB/s)
// Example: with ReadTimeout=30s, bytesPerTimeout = 4000 * 30 = 120KB
// After reading 1MB: multiplier = 1,000,000/120,000 + 1 ≈ 9, deadline = 30s * 9 = 270s
bytesPerTimeout := calculateBytesPerTimeout(c.ReadTimeout)
timeoutMultiplier := time.Duration(c.bytesRead/bytesPerTimeout + 1)
err := c.Conn.SetReadDeadline(time.Now().Add(c.ReadTimeout * timeoutMultiplier))
if err != nil {
return 0, err
}
}
count, e = c.Conn.Read(b)
if e == nil {
stats.BytesIn(int64(count))
c.bytesRead += int64(count)
}
return
}
func (c *Conn) Write(b []byte) (count int, e error) {
if c.WriteTimeout != 0 {
now := time.Now()
// Calculate timeout with two components:
// 1. Base timeout scaled by cumulative data (minimum throughput of 4KB/s)
// 2. Additional grace period if there was a gap since last write (for chunk fetch delays)
// Calculate expected bytes per timeout period based on minimum throughput (4KB/s)
// Example: with WriteTimeout=30s, bytesPerTimeout = 4000 * 30 = 120KB
// After writing 1MB: multiplier = 1,000,000/120,000 + 1 ≈ 9, baseTimeout = 30s * 9 = 270s
bytesPerTimeout := calculateBytesPerTimeout(c.WriteTimeout)
timeoutMultiplier := time.Duration(c.bytesWritten/bytesPerTimeout + 1)
baseTimeout := c.WriteTimeout * timeoutMultiplier
// If it's been a while since last write, add grace time for server-side chunk fetches
// But cap it to avoid keeping slow clients connected indefinitely
//
// The comparison uses unscaled WriteTimeout intentionally: triggers grace when idle time
// exceeds base timeout, independent of throughput scaling.
if !c.lastWrite.IsZero() {
timeSinceLastWrite := now.Sub(c.lastWrite)
if timeSinceLastWrite > c.WriteTimeout {
// Add grace time capped at graceTimeCapMultiplier * scaled timeout.
// This allows total deadline up to 4x scaled timeout for server-side delays.
//
// Example: WriteTimeout=30s, 1MB written (multiplier≈9), baseTimeout=270s
// If 400s gap occurs fetching chunks: graceTime capped at 270s*3=810s
// Final deadline: 270s + 810s = 1080s (~18min) to accommodate slow storage
// But if only 50s gap: graceTime = 50s, final deadline = 270s + 50s = 320s
graceTime := timeSinceLastWrite
if graceTime > baseTimeout*graceTimeCapMultiplier {
graceTime = baseTimeout * graceTimeCapMultiplier
}
baseTimeout += graceTime
}
}
err := c.Conn.SetWriteDeadline(now.Add(baseTimeout))
if err != nil {
return 0, err
}
}
count, e = c.Conn.Write(b)
if e == nil {
stats.BytesOut(int64(count))
c.bytesWritten += int64(count)
c.lastWrite = time.Now()
}
return
}
func (c *Conn) Close() error {
err := c.Conn.Close()
if err == nil {
if !c.isClosed {
stats.ConnectionClose()
c.isClosed = true
}
}
return err
}
func NewListener(addr string, timeout time.Duration) (ipListener net.Listener, err error) {
listener, err := net.Listen("tcp", addr)
if err != nil {
return
}
ipListener = &Listener{
Listener: listener,
ReadTimeout: timeout,
WriteTimeout: timeout,
}
return
}
func NewIpAndLocalListeners(host string, port int, timeout time.Duration) (ipListener net.Listener, localListener net.Listener, err error) {
listener, err := net.Listen("tcp", JoinHostPort(host, port))
if err != nil {
return
}
ipListener = &Listener{
Listener: listener,
ReadTimeout: timeout,
WriteTimeout: timeout,
}
if host != "localhost" && host != "" && host != "0.0.0.0" && host != "127.0.0.1" && host != "[::]" && host != "[::1]" {
listener, err = net.Listen("tcp", JoinHostPort("localhost", port))
if err != nil {
glog.V(0).Infof("skip starting on %s:%d: %v", host, port, err)
return ipListener, nil, nil
}
localListener = &Listener{
Listener: listener,
ReadTimeout: timeout,
WriteTimeout: timeout,
}
}
return
}
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