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stream_listener.go
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/
stream_listener.go
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package socket_listener
import (
"bufio"
"crypto/tls"
"errors"
"fmt"
"io"
"net"
"net/url"
"os"
"strconv"
"sync"
"syscall"
"time"
"github.com/influxdata/telegraf"
"github.com/influxdata/telegraf/config"
"github.com/influxdata/telegraf/internal"
)
type hasSetReadBuffer interface {
SetReadBuffer(bytes int) error
}
type streamListener struct {
Encoding string
ReadBufferSize int
MaxConnections int
ReadTimeout config.Duration
KeepAlivePeriod *config.Duration
Splitter bufio.SplitFunc
Parser telegraf.Parser
Log telegraf.Logger
listener net.Listener
connections map[net.Conn]struct{}
path string
wg sync.WaitGroup
sync.Mutex
}
func (l *streamListener) setupTCP(u *url.URL, tlsCfg *tls.Config) error {
var err error
if tlsCfg == nil {
l.listener, err = net.Listen(u.Scheme, u.Host)
} else {
l.listener, err = tls.Listen(u.Scheme, u.Host, tlsCfg)
}
return err
}
func (l *streamListener) setupUnix(u *url.URL, tlsCfg *tls.Config, socketMode string) error {
err := os.Remove(u.Path)
if err != nil && !errors.Is(err, os.ErrNotExist) {
return fmt.Errorf("removing socket failed: %w", err)
}
if tlsCfg == nil {
l.listener, err = net.Listen(u.Scheme, u.Path)
} else {
l.listener, err = tls.Listen(u.Scheme, u.Path, tlsCfg)
}
if err != nil {
return err
}
l.path = u.Path
// Set permissions on socket
if socketMode != "" {
// Convert from octal in string to int
i, err := strconv.ParseUint(socketMode, 8, 32)
if err != nil {
return fmt.Errorf("converting socket mode failed: %w", err)
}
perm := os.FileMode(uint32(i))
if err := os.Chmod(u.Path, perm); err != nil {
return fmt.Errorf("changing socket permissions failed: %w", err)
}
}
return nil
}
func (l *streamListener) setupConnection(conn net.Conn) error {
if c, ok := conn.(*tls.Conn); ok {
conn = c.NetConn()
}
addr := conn.RemoteAddr().String()
l.Lock()
if l.MaxConnections > 0 && len(l.connections) >= l.MaxConnections {
l.Unlock()
// Ignore the returned error as we cannot do anything about it anyway
_ = conn.Close()
return fmt.Errorf("unable to accept connection from %q: too many connections", addr)
}
l.connections[conn] = struct{}{}
l.Unlock()
if l.ReadBufferSize > 0 {
if rb, ok := conn.(hasSetReadBuffer); ok {
if err := rb.SetReadBuffer(l.ReadBufferSize); err != nil {
l.Log.Warnf("Setting read buffer on socket failed: %v", err)
}
} else {
l.Log.Warn("Cannot set read buffer on socket of this type")
}
}
// Set keep alive handlings
if l.KeepAlivePeriod != nil {
tcpConn, ok := conn.(*net.TCPConn)
if !ok {
l.Log.Warnf("connection not a TCP connection (%T)", conn)
}
if *l.KeepAlivePeriod == 0 {
if err := tcpConn.SetKeepAlive(false); err != nil {
l.Log.Warnf("Cannot set keep-alive: %v", err)
}
} else {
if err := tcpConn.SetKeepAlive(true); err != nil {
l.Log.Warnf("Cannot set keep-alive: %v", err)
}
err := tcpConn.SetKeepAlivePeriod(time.Duration(*l.KeepAlivePeriod))
if err != nil {
l.Log.Warnf("Cannot set keep-alive period: %v", err)
}
}
}
return nil
}
func (l *streamListener) closeConnection(conn net.Conn) {
addr := conn.RemoteAddr().String()
if err := conn.Close(); err != nil && !errors.Is(err, net.ErrClosed) && !errors.Is(err, syscall.EPIPE) {
l.Log.Warnf("Cannot close connection to %q: %v", addr, err)
}
delete(l.connections, conn)
}
func (l *streamListener) addr() net.Addr {
return l.listener.Addr()
}
func (l *streamListener) close() error {
if err := l.listener.Close(); err != nil {
return err
}
l.Lock()
for conn := range l.connections {
l.closeConnection(conn)
}
l.Unlock()
l.wg.Wait()
if l.path != "" {
err := os.Remove(l.path)
if err != nil && !errors.Is(err, os.ErrNotExist) {
// Ignore file-not-exists errors when removing the socket
return err
}
}
return nil
}
func (l *streamListener) listen(acc telegraf.Accumulator) {
l.connections = make(map[net.Conn]struct{})
l.wg.Add(1)
defer l.wg.Done()
var wg sync.WaitGroup
for {
conn, err := l.listener.Accept()
if err != nil {
if !errors.Is(err, net.ErrClosed) {
acc.AddError(err)
}
break
}
if err := l.setupConnection(conn); err != nil {
acc.AddError(err)
continue
}
wg.Add(1)
go func(c net.Conn) {
defer wg.Done()
if err := l.read(acc, c); err != nil {
if !errors.Is(err, io.EOF) && !errors.Is(err, syscall.ECONNRESET) {
acc.AddError(err)
}
}
l.Lock()
l.closeConnection(conn)
l.Unlock()
}(conn)
}
wg.Wait()
}
func (l *streamListener) read(acc telegraf.Accumulator, conn net.Conn) error {
decoder, err := internal.NewStreamContentDecoder(l.Encoding, conn)
if err != nil {
return fmt.Errorf("creating decoder failed: %w", err)
}
timeout := time.Duration(l.ReadTimeout)
scanner := bufio.NewScanner(decoder)
scanner.Split(l.Splitter)
for {
// Set the read deadline, if any, then start reading. The read
// will accept the deadline and return if no or insufficient data
// arrived in time. We need to set the deadline in every cycle as
// it is an ABSOLUTE time and not a timeout.
if timeout > 0 {
deadline := time.Now().Add(timeout)
if err := conn.SetReadDeadline(deadline); err != nil {
return fmt.Errorf("setting read deadline failed: %w", err)
}
}
if !scanner.Scan() {
// Exit if no data arrived e.g. due to timeout or closed connection
break
}
data := scanner.Bytes()
metrics, err := l.Parser.Parse(data)
if err != nil {
acc.AddError(fmt.Errorf("parsing error: %w", err))
l.Log.Debugf("invalid data for parser: %v", data)
continue
}
for _, m := range metrics {
acc.AddMetric(m)
}
}
if err := scanner.Err(); err != nil {
if errors.Is(err, os.ErrDeadlineExceeded) {
// Ignore the timeout and silently close the connection
l.Log.Debug(err)
return nil
}
if errors.Is(err, net.ErrClosed) {
// Ignore the connection closing of the remote side
return nil
}
return err
}
return nil
}