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package sarama
import (
"crypto/tls"
"encoding/binary"
"fmt"
"io"
"net"
"strconv"
"sync"
"sync/atomic"
"time"
)
// Broker represents a single Kafka broker connection. All operations on this object are entirely concurrency-safe.
type Broker struct {
id int32
addr string
conf *Config
correlationID int32
conn net.Conn
connErr error
lock sync.Mutex
opened int32
responses chan responsePromise
done chan bool
}
type responsePromise struct {
correlationID int32
packets chan []byte
errors chan error
}
// NewBroker creates and returns a Broker targetting the given host:port address.
// This does not attempt to actually connect, you have to call Open() for that.
func NewBroker(addr string) *Broker {
return &Broker{id: -1, addr: addr}
}
// Open tries to connect to the Broker if it is not already connected or connecting, but does not block
// waiting for the connection to complete. This means that any subsequent operations on the broker will
// block waiting for the connection to succeed or fail. To get the effect of a fully synchronous Open call,
// follow it by a call to Connected(). The only errors Open will return directly are ConfigurationError or
// AlreadyConnected. If conf is nil, the result of NewConfig() is used.
func (b *Broker) Open(conf *Config) error {
if !atomic.CompareAndSwapInt32(&b.opened, 0, 1) {
return ErrAlreadyConnected
}
if conf == nil {
conf = NewConfig()
}
err := conf.Validate()
if err != nil {
return err
}
b.lock.Lock()
go withRecover(func() {
defer b.lock.Unlock()
dialer := net.Dialer{
Timeout: conf.Net.DialTimeout,
KeepAlive: conf.Net.KeepAlive,
}
if conf.Net.TLS.Enable {
b.conn, b.connErr = tls.DialWithDialer(&dialer, "tcp", b.addr, conf.Net.TLS.Config)
} else {
b.conn, b.connErr = dialer.Dial("tcp", b.addr)
}
if b.connErr != nil {
Logger.Printf("Failed to connect to broker %s: %s\n", b.addr, b.connErr)
b.conn = nil
atomic.StoreInt32(&b.opened, 0)
return
}
b.conn = newBufConn(b.conn)
b.conf = conf
if conf.Net.SASL.Enable {
b.connErr = b.sendAndReceiveSASLPlainAuth()
if b.connErr != nil {
err = b.conn.Close()
if err == nil {
Logger.Printf("Closed connection to broker %s\n", b.addr)
} else {
Logger.Printf("Error while closing connection to broker %s: %s\n", b.addr, err)
}
b.conn = nil
atomic.StoreInt32(&b.opened, 0)
return
}
}
b.done = make(chan bool)
b.responses = make(chan responsePromise, b.conf.Net.MaxOpenRequests-1)
if b.id >= 0 {
Logger.Printf("Connected to broker at %s (registered as #%d)\n", b.addr, b.id)
} else {
Logger.Printf("Connected to broker at %s (unregistered)\n", b.addr)
}
go withRecover(b.responseReceiver)
})
return nil
}
// Connected returns true if the broker is connected and false otherwise. If the broker is not
// connected but it had tried to connect, the error from that connection attempt is also returned.
func (b *Broker) Connected() (bool, error) {
b.lock.Lock()
defer b.lock.Unlock()
return b.conn != nil, b.connErr
}
func (b *Broker) Close() error {
b.lock.Lock()
defer b.lock.Unlock()
if b.conn == nil {
return ErrNotConnected
}
close(b.responses)
<-b.done
err := b.conn.Close()
b.conn = nil
b.connErr = nil
b.done = nil
b.responses = nil
if err == nil {
Logger.Printf("Closed connection to broker %s\n", b.addr)
} else {
Logger.Printf("Error while closing connection to broker %s: %s\n", b.addr, err)
}
atomic.StoreInt32(&b.opened, 0)
return err
}
// ID returns the broker ID retrieved from Kafka's metadata, or -1 if that is not known.
func (b *Broker) ID() int32 {
return b.id
}
// Addr returns the broker address as either retrieved from Kafka's metadata or passed to NewBroker.
func (b *Broker) Addr() string {
return b.addr
}
func (b *Broker) GetMetadata(request *MetadataRequest) (*MetadataResponse, error) {
response := new(MetadataResponse)
err := b.sendAndReceive(request, response)
if err != nil {
return nil, err
}
return response, nil
}
func (b *Broker) GetConsumerMetadata(request *ConsumerMetadataRequest) (*ConsumerMetadataResponse, error) {
response := new(ConsumerMetadataResponse)
err := b.sendAndReceive(request, response)
if err != nil {
return nil, err
}
return response, nil
}
func (b *Broker) GetAvailableOffsets(request *OffsetRequest) (*OffsetResponse, error) {
response := new(OffsetResponse)
err := b.sendAndReceive(request, response)
if err != nil {
return nil, err
}
return response, nil
}
func (b *Broker) Produce(request *ProduceRequest) (*ProduceResponse, error) {
var response *ProduceResponse
var err error
if request.RequiredAcks == NoResponse {
err = b.sendAndReceive(request, nil)
} else {
response = new(ProduceResponse)
err = b.sendAndReceive(request, response)
}
if err != nil {
return nil, err
}
return response, nil
}
func (b *Broker) Fetch(request *FetchRequest) (*FetchResponse, error) {
response := new(FetchResponse)
err := b.sendAndReceive(request, response)
if err != nil {
return nil, err
}
return response, nil
}
func (b *Broker) CommitOffset(request *OffsetCommitRequest) (*OffsetCommitResponse, error) {
response := new(OffsetCommitResponse)
err := b.sendAndReceive(request, response)
if err != nil {
return nil, err
}
return response, nil
}
func (b *Broker) FetchOffset(request *OffsetFetchRequest) (*OffsetFetchResponse, error) {
response := new(OffsetFetchResponse)
err := b.sendAndReceive(request, response)
if err != nil {
return nil, err
}
return response, nil
}
func (b *Broker) JoinGroup(request *JoinGroupRequest) (*JoinGroupResponse, error) {
response := new(JoinGroupResponse)
err := b.sendAndReceive(request, response)
if err != nil {
return nil, err
}
return response, nil
}
func (b *Broker) SyncGroup(request *SyncGroupRequest) (*SyncGroupResponse, error) {
response := new(SyncGroupResponse)
err := b.sendAndReceive(request, response)
if err != nil {
return nil, err
}
return response, nil
}
func (b *Broker) LeaveGroup(request *LeaveGroupRequest) (*LeaveGroupResponse, error) {
response := new(LeaveGroupResponse)
err := b.sendAndReceive(request, response)
if err != nil {
return nil, err
}
return response, nil
}
func (b *Broker) Heartbeat(request *HeartbeatRequest) (*HeartbeatResponse, error) {
response := new(HeartbeatResponse)
err := b.sendAndReceive(request, response)
if err != nil {
return nil, err
}
return response, nil
}
func (b *Broker) ListGroups(request *ListGroupsRequest) (*ListGroupsResponse, error) {
response := new(ListGroupsResponse)
err := b.sendAndReceive(request, response)
if err != nil {
return nil, err
}
return response, nil
}
func (b *Broker) DescribeGroups(request *DescribeGroupsRequest) (*DescribeGroupsResponse, error) {
response := new(DescribeGroupsResponse)
err := b.sendAndReceive(request, response)
if err != nil {
return nil, err
}
return response, nil
}
func (b *Broker) send(rb protocolBody, promiseResponse bool) (*responsePromise, error) {
b.lock.Lock()
defer b.lock.Unlock()
if b.conn == nil {
if b.connErr != nil {
return nil, b.connErr
}
return nil, ErrNotConnected
}
if !b.conf.Version.IsAtLeast(rb.requiredVersion()) {
return nil, ErrUnsupportedVersion
}
req := &request{correlationID: b.correlationID, clientID: b.conf.ClientID, body: rb}
buf, err := encode(req)
if err != nil {
return nil, err
}
err = b.conn.SetWriteDeadline(time.Now().Add(b.conf.Net.WriteTimeout))
if err != nil {
return nil, err
}
_, err = b.conn.Write(buf)
if err != nil {
return nil, err
}
b.correlationID++
if !promiseResponse {
return nil, nil
}
promise := responsePromise{req.correlationID, make(chan []byte), make(chan error)}
b.responses <- promise
return &promise, nil
}
func (b *Broker) sendAndReceive(req protocolBody, res versionedDecoder) error {
promise, err := b.send(req, res != nil)
if err != nil {
return err
}
if promise == nil {
return nil
}
select {
case buf := <-promise.packets:
return versionedDecode(buf, res, req.version())
case err = <-promise.errors:
return err
}
}
func (b *Broker) decode(pd packetDecoder) (err error) {
b.id, err = pd.getInt32()
if err != nil {
return err
}
host, err := pd.getString()
if err != nil {
return err
}
port, err := pd.getInt32()
if err != nil {
return err
}
b.addr = net.JoinHostPort(host, fmt.Sprint(port))
if _, _, err := net.SplitHostPort(b.addr); err != nil {
return err
}
return nil
}
func (b *Broker) encode(pe packetEncoder) (err error) {
host, portstr, err := net.SplitHostPort(b.addr)
if err != nil {
return err
}
port, err := strconv.Atoi(portstr)
if err != nil {
return err
}
pe.putInt32(b.id)
err = pe.putString(host)
if err != nil {
return err
}
pe.putInt32(int32(port))
return nil
}
func (b *Broker) responseReceiver() {
var dead error
header := make([]byte, 8)
for response := range b.responses {
if dead != nil {
response.errors <- dead
continue
}
err := b.conn.SetReadDeadline(time.Now().Add(b.conf.Net.ReadTimeout))
if err != nil {
dead = err
response.errors <- err
continue
}
_, err = io.ReadFull(b.conn, header)
if err != nil {
dead = err
response.errors <- err
continue
}
decodedHeader := responseHeader{}
err = decode(header, &decodedHeader)
if err != nil {
dead = err
response.errors <- err
continue
}
if decodedHeader.correlationID != response.correlationID {
// TODO if decoded ID < cur ID, discard until we catch up
// TODO if decoded ID > cur ID, save it so when cur ID catches up we have a response
dead = PacketDecodingError{fmt.Sprintf("correlation ID didn't match, wanted %d, got %d", response.correlationID, decodedHeader.correlationID)}
response.errors <- dead
continue
}
buf := make([]byte, decodedHeader.length-4)
_, err = io.ReadFull(b.conn, buf)
if err != nil {
dead = err
response.errors <- err
continue
}
response.packets <- buf
}
close(b.done)
}
// Kafka 0.10.0 plans to support SASL Plain and Kerberos as per PR #812 (KIP-43)/(JIRA KAFKA-3149)
// Some hosted kafka services such as IBM Message Hub already offer SASL/PLAIN auth with Kafka 0.9
//
// In SASL Plain, Kafka expects the auth header to be in the following format
// Message format (from https://tools.ietf.org/html/rfc4616):
//
// message = [authzid] UTF8NUL authcid UTF8NUL passwd
// authcid = 1*SAFE ; MUST accept up to 255 octets
// authzid = 1*SAFE ; MUST accept up to 255 octets
// passwd = 1*SAFE ; MUST accept up to 255 octets
// UTF8NUL = %x00 ; UTF-8 encoded NUL character
//
// SAFE = UTF1 / UTF2 / UTF3 / UTF4
// ;; any UTF-8 encoded Unicode character except NUL
//
// When credentials are valid, Kafka returns a 4 byte array of null characters.
// When credentials are invalid, Kafka closes the connection. This does not seem to be the ideal way
// of responding to bad credentials but thats how its being done today.
func (b *Broker) sendAndReceiveSASLPlainAuth() error {
length := 1 + len(b.conf.Net.SASL.User) + 1 + len(b.conf.Net.SASL.Password)
authBytes := make([]byte, length+4) //4 byte length header + auth data
binary.BigEndian.PutUint32(authBytes, uint32(length))
copy(authBytes[4:], []byte("\x00"+b.conf.Net.SASL.User+"\x00"+b.conf.Net.SASL.Password))
err := b.conn.SetWriteDeadline(time.Now().Add(b.conf.Net.WriteTimeout))
if err != nil {
Logger.Printf("Failed to set write deadline when doing SASL auth with broker %s: %s\n", b.addr, err.Error())
return err
}
_, err = b.conn.Write(authBytes)
if err != nil {
Logger.Printf("Failed to write SASL auth header to broker %s: %s\n", b.addr, err.Error())
return err
}
header := make([]byte, 4)
n, err := io.ReadFull(b.conn, header)
// If the credentials are valid, we would get a 4 byte response filled with null characters.
// Otherwise, the broker closes the connection and we get an EOF
if err != nil {
Logger.Printf("Failed to read response while authenticating with SASL to broker %s: %s\n", b.addr, err.Error())
return err
}
Logger.Printf("SASL authentication successful with broker %s:%v - %v\n", b.addr, n, header)
return nil
}