src/go/plugin/go.d/pkg/socket/client.go
// SPDX-License-Identifier: GPL-3.0-or-later
package socket
import (
"bufio"
"crypto/tls"
"errors"
"net"
"time"
)
// New returns a new pointer to a socket client given the socket
// type (IP, TCP, UDP, UNIX), a network address (IP/domain:port),
// a timeout and a TLS config. It supports both IPv4 and IPv6 address
// and reuses connection where possible.
func New(config Config) *Socket {
return &Socket{
Config: config,
conn: nil,
}
}
// Socket is the implementation of a socket client.
type Socket struct {
Config
conn net.Conn
}
// Connect connects to the Socket address on the named network.
// If the address is a domain name it will also perform the DNS resolution.
// Address like :80 will attempt to connect to the localhost.
// The config timeout and TLS config will be used.
func (s *Socket) Connect() error {
network, address := networkType(s.Address)
var conn net.Conn
var err error
if s.TLSConf == nil {
conn, err = net.DialTimeout(network, address, s.ConnectTimeout)
} else {
var d net.Dialer
d.Timeout = s.ConnectTimeout
conn, err = tls.DialWithDialer(&d, network, address, s.TLSConf)
}
if err != nil {
return err
}
s.conn = conn
return nil
}
// Disconnect closes the connection.
// Any in-flight commands will be cancelled and return errors.
func (s *Socket) Disconnect() (err error) {
if s.conn != nil {
err = s.conn.Close()
s.conn = nil
}
return err
}
// Command writes the command string to the connection and passed the
// response bytes line by line to the process function. It uses the
// timeout value from the Socket config and returns read, write and
// timeout errors if any. If a timeout occurs during the processing
// of the responses this function will stop processing and return a
// timeout error.
func (s *Socket) Command(command string, process Processor) error {
if s.conn == nil {
return errors.New("cannot send command on nil connection")
}
if err := write(command, s.conn, s.WriteTimeout); err != nil {
return err
}
return read(s.conn, process, s.ReadTimeout)
}
func write(command string, writer net.Conn, timeout time.Duration) error {
if writer == nil {
return errors.New("attempt to write on nil connection")
}
if err := writer.SetWriteDeadline(time.Now().Add(timeout)); err != nil {
return err
}
_, err := writer.Write([]byte(command))
return err
}
func read(reader net.Conn, process Processor, timeout time.Duration) error {
if process == nil {
return errors.New("process func is nil")
}
if reader == nil {
return errors.New("attempt to read on nil connection")
}
if err := reader.SetReadDeadline(time.Now().Add(timeout)); err != nil {
return err
}
scanner := bufio.NewScanner(reader)
for scanner.Scan() && process(scanner.Bytes()) {
}
return scanner.Err()
}