1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074
|
package kafka
import (
"bufio"
"errors"
"fmt"
"math"
"net"
"os"
"path/filepath"
"runtime"
"sync"
"sync/atomic"
"time"
)
var (
errInvalidWriteTopic = errors.New("writes must NOT set Topic on kafka.Message")
errInvalidWritePartition = errors.New("writes must NOT set Partition on kafka.Message")
)
// Broker carries the metadata associated with a kafka broker.
type Broker struct {
Host string
Port int
ID int
Rack string
}
// Partition carries the metadata associated with a kafka partition.
type Partition struct {
Topic string
Leader Broker
Replicas []Broker
Isr []Broker
ID int
}
// Conn represents a connection to a kafka broker.
//
// Instances of Conn are safe to use concurrently from multiple goroutines.
type Conn struct {
// base network connection
conn net.Conn
// offset management (synchronized on the mutex field)
mutex sync.Mutex
offset int64
// read buffer (synchronized on rlock)
rlock sync.Mutex
rbuf bufio.Reader
// write buffer (synchronized on wlock)
wlock sync.Mutex
wbuf bufio.Writer
// deadline management
wdeadline connDeadline
rdeadline connDeadline
// immutable values of the connection object
clientID string
topic string
partition int32
fetchMaxBytes int32
fetchMinSize int32
// correlation ID generator (synchronized on wlock)
correlationID int32
// number of replica acks required when publishing to a partition
requiredAcks int32
}
// ConnConfig is a configuration object used to create new instances of Conn.
type ConnConfig struct {
ClientID string
Topic string
Partition int
}
var (
// DefaultClientID is the default value used as ClientID of kafka
// connections.
DefaultClientID string
)
func init() {
progname := filepath.Base(os.Args[0])
hostname, _ := os.Hostname()
DefaultClientID = fmt.Sprintf("%s@%s (github.com/segmentio/kafka-go)", progname, hostname)
}
// NewConn returns a new kafka connection for the given topic and partition.
func NewConn(conn net.Conn, topic string, partition int) *Conn {
return NewConnWith(conn, ConnConfig{
Topic: topic,
Partition: partition,
})
}
// NewConnWith returns a new kafka connection configured with config.
// The offset is initialized to FirstOffset.
func NewConnWith(conn net.Conn, config ConnConfig) *Conn {
if len(config.ClientID) == 0 {
config.ClientID = DefaultClientID
}
if config.Partition < 0 || config.Partition > math.MaxInt32 {
panic(fmt.Sprintf("invalid partition number: %d", config.Partition))
}
c := &Conn{
conn: conn,
rbuf: *bufio.NewReader(conn),
wbuf: *bufio.NewWriter(conn),
clientID: config.ClientID,
topic: config.Topic,
partition: int32(config.Partition),
offset: FirstOffset,
requiredAcks: -1,
}
// The fetch request needs to ask for a MaxBytes value that is at least
// enough to load the control data of the response. To avoid having to
// recompute it on every read, it is cached here in the Conn value.
c.fetchMinSize = (fetchResponseV2{
Topics: []fetchResponseTopicV2{{
TopicName: config.Topic,
Partitions: []fetchResponsePartitionV2{{
Partition: int32(config.Partition),
MessageSet: messageSet{{}},
}},
}},
}).size()
c.fetchMaxBytes = math.MaxInt32 - c.fetchMinSize
return c
}
// DeleteTopics deletes the specified topics.
func (c *Conn) DeleteTopics(topics ...string) error {
_, err := c.deleteTopics(deleteTopicsRequestV1{
Topics: topics,
})
return err
}
// describeGroups retrieves the specified groups
//
// See http://kafka.apache.org/protocol.html#The_Messages_DescribeGroups
func (c *Conn) describeGroups(request describeGroupsRequestV1) (describeGroupsResponseV1, error) {
var response describeGroupsResponseV1
err := c.readOperation(
func(deadline time.Time, id int32) error {
return c.writeRequest(describeGroupsRequest, v1, id, request)
},
func(deadline time.Time, size int) error {
return expectZeroSize(func() (remain int, err error) {
return (&response).readFrom(&c.rbuf, size)
}())
},
)
if err != nil {
return describeGroupsResponseV1{}, err
}
for _, group := range response.Groups {
if group.ErrorCode != 0 {
return describeGroupsResponseV1{}, Error(group.ErrorCode)
}
}
return response, nil
}
// findCoordinator finds the coordinator for the specified group or transaction
//
// See http://kafka.apache.org/protocol.html#The_Messages_FindCoordinator
func (c *Conn) findCoordinator(request findCoordinatorRequestV0) (findCoordinatorResponseV0, error) {
var response findCoordinatorResponseV0
err := c.readOperation(
func(deadline time.Time, id int32) error {
return c.writeRequest(groupCoordinatorRequest, v0, id, request)
},
func(deadline time.Time, size int) error {
return expectZeroSize(func() (remain int, err error) {
return (&response).readFrom(&c.rbuf, size)
}())
},
)
if err != nil {
return findCoordinatorResponseV0{}, err
}
if response.ErrorCode != 0 {
return findCoordinatorResponseV0{}, Error(response.ErrorCode)
}
return response, nil
}
// heartbeat sends a heartbeat message required by consumer groups
//
// See http://kafka.apache.org/protocol.html#The_Messages_Heartbeat
func (c *Conn) heartbeat(request heartbeatRequestV0) (heartbeatResponseV0, error) {
var response heartbeatResponseV0
err := c.writeOperation(
func(deadline time.Time, id int32) error {
return c.writeRequest(heartbeatRequest, v0, id, request)
},
func(deadline time.Time, size int) error {
return expectZeroSize(func() (remain int, err error) {
return (&response).readFrom(&c.rbuf, size)
}())
},
)
if err != nil {
return heartbeatResponseV0{}, err
}
if response.ErrorCode != 0 {
return heartbeatResponseV0{}, Error(response.ErrorCode)
}
return response, nil
}
// joinGroup attempts to join a consumer group
//
// See http://kafka.apache.org/protocol.html#The_Messages_JoinGroup
func (c *Conn) joinGroup(request joinGroupRequestV1) (joinGroupResponseV1, error) {
var response joinGroupResponseV1
err := c.writeOperation(
func(deadline time.Time, id int32) error {
return c.writeRequest(joinGroupRequest, v1, id, request)
},
func(deadline time.Time, size int) error {
return expectZeroSize(func() (remain int, err error) {
return (&response).readFrom(&c.rbuf, size)
}())
},
)
if err != nil {
return joinGroupResponseV1{}, err
}
if response.ErrorCode != 0 {
return joinGroupResponseV1{}, Error(response.ErrorCode)
}
return response, nil
}
// leaveGroup leaves the consumer from the consumer group
//
// See http://kafka.apache.org/protocol.html#The_Messages_LeaveGroup
func (c *Conn) leaveGroup(request leaveGroupRequestV0) (leaveGroupResponseV0, error) {
var response leaveGroupResponseV0
err := c.writeOperation(
func(deadline time.Time, id int32) error {
return c.writeRequest(leaveGroupRequest, v0, id, request)
},
func(deadline time.Time, size int) error {
return expectZeroSize(func() (remain int, err error) {
return (&response).readFrom(&c.rbuf, size)
}())
},
)
if err != nil {
return leaveGroupResponseV0{}, err
}
if response.ErrorCode != 0 {
return leaveGroupResponseV0{}, Error(response.ErrorCode)
}
return response, nil
}
// listGroups lists all the consumer groups
//
// See http://kafka.apache.org/protocol.html#The_Messages_ListGroups
func (c *Conn) listGroups(request listGroupsRequestV1) (listGroupsResponseV1, error) {
var response listGroupsResponseV1
err := c.readOperation(
func(deadline time.Time, id int32) error {
return c.writeRequest(listGroupsRequest, v1, id, request)
},
func(deadline time.Time, size int) error {
return expectZeroSize(func() (remain int, err error) {
return (&response).readFrom(&c.rbuf, size)
}())
},
)
if err != nil {
return listGroupsResponseV1{}, err
}
if response.ErrorCode != 0 {
return listGroupsResponseV1{}, Error(response.ErrorCode)
}
return response, nil
}
// offsetCommit commits the specified topic partition offsets
//
// See http://kafka.apache.org/protocol.html#The_Messages_OffsetCommit
func (c *Conn) offsetCommit(request offsetCommitRequestV2) (offsetCommitResponseV2, error) {
var response offsetCommitResponseV2
err := c.writeOperation(
func(deadline time.Time, id int32) error {
return c.writeRequest(offsetCommitRequest, v2, id, request)
},
func(deadline time.Time, size int) error {
return expectZeroSize(func() (remain int, err error) {
return (&response).readFrom(&c.rbuf, size)
}())
},
)
if err != nil {
return offsetCommitResponseV2{}, err
}
for _, r := range response.Responses {
for _, pr := range r.PartitionResponses {
if pr.ErrorCode != 0 {
return offsetCommitResponseV2{}, Error(pr.ErrorCode)
}
}
}
return response, nil
}
// offsetFetch fetches the offsets for the specified topic partitions.
// -1 indicates that there is no offset saved for the partition.
//
// See http://kafka.apache.org/protocol.html#The_Messages_OffsetFetch
func (c *Conn) offsetFetch(request offsetFetchRequestV1) (offsetFetchResponseV1, error) {
var response offsetFetchResponseV1
err := c.readOperation(
func(deadline time.Time, id int32) error {
return c.writeRequest(offsetFetchRequest, v1, id, request)
},
func(deadline time.Time, size int) error {
return expectZeroSize(func() (remain int, err error) {
return (&response).readFrom(&c.rbuf, size)
}())
},
)
if err != nil {
return offsetFetchResponseV1{}, err
}
for _, r := range response.Responses {
for _, pr := range r.PartitionResponses {
if pr.ErrorCode != 0 {
return offsetFetchResponseV1{}, Error(pr.ErrorCode)
}
}
}
return response, nil
}
// syncGroups completes the handshake to join a consumer group
//
// See http://kafka.apache.org/protocol.html#The_Messages_SyncGroup
func (c *Conn) syncGroups(request syncGroupRequestV0) (syncGroupResponseV0, error) {
var response syncGroupResponseV0
err := c.readOperation(
func(deadline time.Time, id int32) error {
return c.writeRequest(syncGroupRequest, v0, id, request)
},
func(deadline time.Time, size int) error {
return expectZeroSize(func() (remain int, err error) {
return (&response).readFrom(&c.rbuf, size)
}())
},
)
if err != nil {
return syncGroupResponseV0{}, err
}
if response.ErrorCode != 0 {
return syncGroupResponseV0{}, Error(response.ErrorCode)
}
return response, nil
}
// Close closes the kafka connection.
func (c *Conn) Close() error {
return c.conn.Close()
}
// LocalAddr returns the local network address.
func (c *Conn) LocalAddr() net.Addr {
return c.conn.LocalAddr()
}
// RemoteAddr returns the remote network address.
func (c *Conn) RemoteAddr() net.Addr {
return c.conn.RemoteAddr()
}
// SetDeadline sets the read and write deadlines associated with the connection.
// It is equivalent to calling both SetReadDeadline and SetWriteDeadline.
//
// A deadline is an absolute time after which I/O operations fail with a timeout
// (see type Error) instead of blocking. The deadline applies to all future and
// pending I/O, not just the immediately following call to Read or Write. After
// a deadline has been exceeded, the connection may be closed if it was found to
// be in an unrecoverable state.
//
// A zero value for t means I/O operations will not time out.
func (c *Conn) SetDeadline(t time.Time) error {
c.rdeadline.setDeadline(t)
c.wdeadline.setDeadline(t)
return nil
}
// SetReadDeadline sets the deadline for future Read calls and any
// currently-blocked Read call.
// A zero value for t means Read will not time out.
func (c *Conn) SetReadDeadline(t time.Time) error {
c.rdeadline.setDeadline(t)
return nil
}
// SetWriteDeadline sets the deadline for future Write calls and any
// currently-blocked Write call.
// Even if write times out, it may return n > 0, indicating that some of the
// data was successfully written.
// A zero value for t means Write will not time out.
func (c *Conn) SetWriteDeadline(t time.Time) error {
c.wdeadline.setDeadline(t)
return nil
}
// Offset returns the current offset of the connection as pair of integers,
// where the first one is an offset value and the second one indicates how
// to interpret it.
//
// See Seek for more details about the offset and whence values.
func (c *Conn) Offset() (offset int64, whence int) {
c.mutex.Lock()
offset = c.offset
c.mutex.Unlock()
switch offset {
case FirstOffset:
offset = 0
whence = SeekStart
case LastOffset:
offset = 0
whence = SeekEnd
default:
whence = SeekAbsolute
}
return
}
const (
SeekStart = 0 // Seek relative to the first offset available in the partition.
SeekAbsolute = 1 // Seek to an absolute offset.
SeekEnd = 2 // Seek relative to the last offset available in the partition.
SeekCurrent = 3 // Seek relative to the current offset.
)
// Seek sets the offset for the next read or write operation according to whence, which
// should be one of SeekStart, SeekAbsolute, SeekEnd, or SeekCurrent.
// When seeking relative to the end, the offset is subtracted from the current offset.
// Note that for historical reasons, these do not align with the usual whence constants
// as in lseek(2) or os.Seek.
// The method returns the new absolute offset of the connection.
func (c *Conn) Seek(offset int64, whence int) (int64, error) {
switch whence {
case SeekStart, SeekAbsolute, SeekEnd, SeekCurrent:
default:
return 0, fmt.Errorf("whence must be one of 0, 1, 2, or 3. (whence = %d)", whence)
}
if whence == SeekAbsolute {
c.mutex.Lock()
unchanged := offset == c.offset
c.mutex.Unlock()
if unchanged {
return offset, nil
}
}
if whence == SeekCurrent {
c.mutex.Lock()
offset = c.offset + offset
c.mutex.Unlock()
}
first, last, err := c.ReadOffsets()
if err != nil {
return 0, err
}
switch whence {
case SeekStart:
offset = first + offset
case SeekEnd:
offset = last - offset
}
if offset < first || offset > last {
return 0, OffsetOutOfRange
}
c.mutex.Lock()
c.offset = offset
c.mutex.Unlock()
return offset, nil
}
// Read reads the message at the current offset from the connection, advancing
// the offset on success so the next call to a read method will produce the next
// message.
// The method returns the number of bytes read, or an error if something went
// wrong.
//
// While it is safe to call Read concurrently from multiple goroutines it may
// be hard for the program to predict the results as the connection offset will
// be read and written by multiple goroutines, they could read duplicates, or
// messages may be seen by only some of the goroutines.
//
// The method fails with io.ErrShortBuffer if the buffer passed as argument is
// too small to hold the message value.
//
// This method is provided to satisfy the net.Conn interface but is much less
// efficient than using the more general purpose ReadBatch method.
func (c *Conn) Read(b []byte) (int, error) {
batch := c.ReadBatch(1, len(b))
n, err := batch.Read(b)
return n, coalesceErrors(silentEOF(err), batch.Close())
}
// ReadMessage reads the message at the current offset from the connection,
// advancing the offset on success so the next call to a read method will
// produce the next message.
//
// Because this method allocate memory buffers for the message key and value
// it is less memory-efficient than Read, but has the advantage of never
// failing with io.ErrShortBuffer.
//
// While it is safe to call Read concurrently from multiple goroutines it may
// be hard for the program to predict the results as the connection offset will
// be read and written by multiple goroutines, they could read duplicates, or
// messages may be seen by only some of the goroutines.
//
// This method is provided for convenience purposes but is much less efficient
// than using the more general purpose ReadBatch method.
func (c *Conn) ReadMessage(maxBytes int) (Message, error) {
batch := c.ReadBatch(1, maxBytes)
msg, err := batch.ReadMessage()
return msg, coalesceErrors(silentEOF(err), batch.Close())
}
// ReadBatch reads a batch of messages from the kafka server. The method always
// returns a non-nil Batch value. If an error occurred, either sending the fetch
// request or reading the response, the error will be made available by the
// returned value of the batch's Close method.
//
// While it is safe to call ReadBatch concurrently from multiple goroutines it
// may be hard for the program to predict the results as the connection offset
// will be read and written by multiple goroutines, they could read duplicates,
// or messages may be seen by only some of the goroutines.
//
// A program doesn't specify the number of messages in wants from a batch, but
// gives the minimum and maximum number of bytes that it wants to receive from
// the kafka server.
func (c *Conn) ReadBatch(minBytes, maxBytes int) *Batch {
var adjustedDeadline time.Time
var maxFetch = int(c.fetchMaxBytes)
if minBytes < 0 || minBytes > maxFetch {
return &Batch{err: fmt.Errorf("kafka.(*Conn).ReadBatch: minBytes of %d out of [1,%d] bounds", minBytes, maxFetch)}
}
if maxBytes < 0 || maxBytes > maxFetch {
return &Batch{err: fmt.Errorf("kafka.(*Conn).ReadBatch: maxBytes of %d out of [1,%d] bounds", maxBytes, maxFetch)}
}
if minBytes > maxBytes {
return &Batch{err: fmt.Errorf("kafka.(*Conn).ReadBatch: minBytes (%d) > maxBytes (%d)", minBytes, maxBytes)}
}
offset, err := c.Seek(c.Offset())
if err != nil {
return &Batch{err: dontExpectEOF(err)}
}
id, err := c.doRequest(&c.rdeadline, func(deadline time.Time, id int32) error {
now := time.Now()
deadline = adjustDeadlineForRTT(deadline, now, defaultRTT)
adjustedDeadline = deadline
return writeFetchRequestV2(
&c.wbuf,
id,
c.clientID,
c.topic,
c.partition,
offset,
minBytes,
maxBytes+int(c.fetchMinSize),
deadlineToTimeout(deadline, now),
)
})
if err != nil {
return &Batch{err: dontExpectEOF(err)}
}
_, size, lock, err := c.waitResponse(&c.rdeadline, id)
if err != nil {
return &Batch{err: dontExpectEOF(err)}
}
throttle, highWaterMark, remain, err := readFetchResponseHeader(&c.rbuf, size)
return &Batch{
conn: c,
msgs: newMessageSetReader(&c.rbuf, remain),
deadline: adjustedDeadline,
throttle: duration(throttle),
lock: lock,
topic: c.topic, // topic is copied to Batch to prevent race with Batch.close
partition: int(c.partition), // partition is copied to Batch to prevent race with Batch.close
offset: offset,
highWaterMark: highWaterMark,
err: dontExpectEOF(err),
}
}
// ReadOffset returns the offset of the first message with a timestamp equal or
// greater to t.
func (c *Conn) ReadOffset(t time.Time) (int64, error) {
return c.readOffset(timestamp(t))
}
// ReadFirstOffset returns the first offset available on the connection.
func (c *Conn) ReadFirstOffset() (int64, error) {
return c.readOffset(FirstOffset)
}
// ReadLastOffset returns the last offset available on the connection.
func (c *Conn) ReadLastOffset() (int64, error) {
return c.readOffset(LastOffset)
}
// ReadOffsets returns the absolute first and last offsets of the topic used by
// the connection.
func (c *Conn) ReadOffsets() (first, last int64, err error) {
// We have to submit two different requests to fetch the first and last
// offsets because kafka refuses requests that ask for multiple offsets
// on the same topic and partition.
if first, err = c.ReadFirstOffset(); err != nil {
return
}
if last, err = c.ReadLastOffset(); err != nil {
first = 0 // don't leak the value on error
return
}
return
}
func (c *Conn) readOffset(t int64) (offset int64, err error) {
err = c.readOperation(
func(deadline time.Time, id int32) error {
return writeListOffsetRequestV1(&c.wbuf, id, c.clientID, c.topic, c.partition, t)
},
func(deadline time.Time, size int) error {
return expectZeroSize(readArrayWith(&c.rbuf, size, func(r *bufio.Reader, size int) (int, error) {
// We skip the topic name because we've made a request for
// a single topic.
size, err := discardString(r, size)
if err != nil {
return size, err
}
// Reading the array of partitions, there will be only one
// partition which gives the offset we're looking for.
return readArrayWith(r, size, func(r *bufio.Reader, size int) (int, error) {
var p partitionOffsetV1
size, err := p.readFrom(r, size)
if err != nil {
return size, err
}
if p.ErrorCode != 0 {
return size, Error(p.ErrorCode)
}
offset = p.Offset
return size, nil
})
}))
},
)
return
}
// ReadPartitions returns the list of available partitions for the given list of
// topics.
//
// If the method is called with no topic, it uses the topic configured on the
// connection. If there are none, the method fetches all partitions of the kafka
// cluster.
func (c *Conn) ReadPartitions(topics ...string) (partitions []Partition, err error) {
defaultTopics := [...]string{c.topic}
if len(topics) == 0 && len(c.topic) != 0 {
topics = defaultTopics[:]
}
err = c.readOperation(
func(deadline time.Time, id int32) error {
return c.writeRequest(metadataRequest, v1, id, topicMetadataRequestV1(topics))
},
func(deadline time.Time, size int) error {
var res metadataResponseV1
if err := c.readResponse(size, &res); err != nil {
return err
}
brokers := make(map[int32]Broker, len(res.Brokers))
for _, b := range res.Brokers {
brokers[b.NodeID] = Broker{
Host: b.Host,
Port: int(b.Port),
ID: int(b.NodeID),
Rack: b.Rack,
}
}
makeBrokers := func(ids ...int32) []Broker {
b := make([]Broker, len(ids))
for i, id := range ids {
b[i] = brokers[id]
}
return b
}
for _, t := range res.Topics {
if t.TopicErrorCode != 0 && t.TopicName == c.topic {
// We only report errors if they happened for the topic of
// the connection, otherwise the topic will simply have no
// partitions in the result set.
return Error(t.TopicErrorCode)
}
for _, p := range t.Partitions {
partitions = append(partitions, Partition{
Topic: t.TopicName,
Leader: brokers[p.Leader],
Replicas: makeBrokers(p.Replicas...),
Isr: makeBrokers(p.Isr...),
ID: int(p.PartitionID),
})
}
}
return nil
},
)
return
}
// Write writes a message to the kafka broker that this connection was
// established to. The method returns the number of bytes written, or an error
// if something went wrong.
//
// The operation either succeeds or fail, it never partially writes the message.
//
// This method is exposed to satisfy the net.Conn interface but is less efficient
// than the more general purpose WriteMessages method.
func (c *Conn) Write(b []byte) (int, error) {
return c.WriteCompressedMessages(nil, Message{Value: b})
}
// WriteMessages writes a batch of messages to the connection's topic and
// partition, returning the number of bytes written. The write is an atomic
// operation, it either fully succeeds or fails.
func (c *Conn) WriteMessages(msgs ...Message) (int, error) {
return c.WriteCompressedMessages(nil, msgs...)
}
// WriteCompressedMessages writes a batch of messages to the connection's topic
// and partition, returning the number of bytes written. The write is an atomic
// operation, it either fully succeeds or fails.
//
// If the compression codec is not nil, the messages will be compressed.
func (c *Conn) WriteCompressedMessages(codec CompressionCodec, msgs ...Message) (int, error) {
if len(msgs) == 0 {
return 0, nil
}
writeTime := time.Now()
n := 0
for i, msg := range msgs {
// users may believe they can set the Topic and/or Partition
// on the kafka message.
if msg.Topic != "" && msg.Topic != c.topic {
return 0, errInvalidWriteTopic
}
if msg.Partition != 0 {
return 0, errInvalidWritePartition
}
if msg.Time.IsZero() {
msgs[i].Time = writeTime
}
n += len(msg.Key) + len(msg.Value)
}
err := c.writeOperation(
func(deadline time.Time, id int32) error {
now := time.Now()
deadline = adjustDeadlineForRTT(deadline, now, defaultRTT)
return writeProduceRequestV2(
&c.wbuf,
codec,
id,
c.clientID,
c.topic,
c.partition,
deadlineToTimeout(deadline, now),
int16(atomic.LoadInt32(&c.requiredAcks)),
msgs...,
)
},
func(deadline time.Time, size int) error {
return expectZeroSize(readArrayWith(&c.rbuf, size, func(r *bufio.Reader, size int) (int, error) {
// Skip the topic, we've produced the message to only one topic,
// no need to waste resources loading it in memory.
size, err := discardString(r, size)
if err != nil {
return size, err
}
// Read the list of partitions, there should be only one since
// we've produced a message to a single partition.
size, err = readArrayWith(r, size, func(r *bufio.Reader, size int) (int, error) {
var p produceResponsePartitionV2
size, err := p.readFrom(r, size)
if err == nil && p.ErrorCode != 0 {
err = Error(p.ErrorCode)
}
return size, err
})
if err != nil {
return size, err
}
// The response is trailed by the throttle time, also skipping
// since it's not interesting here.
return discardInt32(r, size)
}))
},
)
if err != nil {
n = 0
}
return n, err
}
// SetRequiredAcks sets the number of acknowledges from replicas that the
// connection requests when producing messages.
func (c *Conn) SetRequiredAcks(n int) error {
switch n {
case -1, 1:
atomic.StoreInt32(&c.requiredAcks, int32(n))
return nil
default:
return InvalidRequiredAcks
}
}
func (c *Conn) writeRequestHeader(apiKey apiKey, apiVersion apiVersion, correlationID int32, size int32) {
hdr := c.requestHeader(apiKey, apiVersion, correlationID)
hdr.Size = (hdr.size() + size) - 4
hdr.writeTo(&c.wbuf)
}
func (c *Conn) writeRequest(apiKey apiKey, apiVersion apiVersion, correlationID int32, req request) error {
hdr := c.requestHeader(apiKey, apiVersion, correlationID)
hdr.Size = (hdr.size() + req.size()) - 4
hdr.writeTo(&c.wbuf)
req.writeTo(&c.wbuf)
return c.wbuf.Flush()
}
func (c *Conn) readResponse(size int, res interface{}) error {
size, err := read(&c.rbuf, size, res)
switch err.(type) {
case Error:
var e error
if size, e = discardN(&c.rbuf, size, size); e != nil {
err = e
}
}
return expectZeroSize(size, err)
}
func (c *Conn) peekResponseSizeAndID() (int32, int32, error) {
b, err := c.rbuf.Peek(8)
if err != nil {
return 0, 0, err
}
size, id := makeInt32(b[:4]), makeInt32(b[4:])
return size, id, nil
}
func (c *Conn) skipResponseSizeAndID() {
c.rbuf.Discard(8)
}
func (c *Conn) readDeadline() time.Time {
return c.rdeadline.deadline()
}
func (c *Conn) writeDeadline() time.Time {
return c.wdeadline.deadline()
}
func (c *Conn) readOperation(write func(time.Time, int32) error, read func(time.Time, int) error) error {
return c.do(&c.rdeadline, write, read)
}
func (c *Conn) writeOperation(write func(time.Time, int32) error, read func(time.Time, int) error) error {
return c.do(&c.wdeadline, write, read)
}
func (c *Conn) do(d *connDeadline, write func(time.Time, int32) error, read func(time.Time, int) error) error {
id, err := c.doRequest(d, write)
if err != nil {
return err
}
deadline, size, lock, err := c.waitResponse(d, id)
if err != nil {
return err
}
if err = read(deadline, size); err != nil {
switch err.(type) {
case Error:
default:
c.conn.Close()
}
}
d.unsetConnReadDeadline()
lock.Unlock()
return err
}
func (c *Conn) doRequest(d *connDeadline, write func(time.Time, int32) error) (id int32, err error) {
c.wlock.Lock()
c.correlationID++
id = c.correlationID
err = write(d.setConnWriteDeadline(c.conn), id)
d.unsetConnWriteDeadline()
if err != nil {
// When an error occurs there's no way to know if the connection is in a
// recoverable state so we're better off just giving up at this point to
// avoid any risk of corrupting the following operations.
c.conn.Close()
}
c.wlock.Unlock()
return
}
func (c *Conn) waitResponse(d *connDeadline, id int32) (deadline time.Time, size int, lock *sync.Mutex, err error) {
for {
var rsz int32
var rid int32
c.rlock.Lock()
deadline = d.setConnReadDeadline(c.conn)
if rsz, rid, err = c.peekResponseSizeAndID(); err != nil {
d.unsetConnReadDeadline()
c.conn.Close()
c.rlock.Unlock()
return
}
if id == rid {
c.skipResponseSizeAndID()
size, lock = int(rsz-4), &c.rlock
return
}
// Optimistically release the read lock if a response has already
// been received but the current operation is not the target for it.
c.rlock.Unlock()
runtime.Gosched()
}
}
func (c *Conn) requestHeader(apiKey apiKey, apiVersion apiVersion, correlationID int32) requestHeader {
return requestHeader{
ApiKey: int16(apiKey),
ApiVersion: int16(apiVersion),
CorrelationID: correlationID,
ClientID: c.clientID,
}
}
// connDeadline is a helper type to implement read/write deadline management on
// the kafka connection.
type connDeadline struct {
mutex sync.Mutex
value time.Time
rconn net.Conn
wconn net.Conn
}
func (d *connDeadline) deadline() time.Time {
d.mutex.Lock()
t := d.value
d.mutex.Unlock()
return t
}
func (d *connDeadline) setDeadline(t time.Time) {
d.mutex.Lock()
d.value = t
if d.rconn != nil {
d.rconn.SetReadDeadline(t)
}
if d.wconn != nil {
d.wconn.SetWriteDeadline(t)
}
d.mutex.Unlock()
}
func (d *connDeadline) setConnReadDeadline(conn net.Conn) time.Time {
d.mutex.Lock()
deadline := d.value
d.rconn = conn
d.rconn.SetReadDeadline(deadline)
d.mutex.Unlock()
return deadline
}
func (d *connDeadline) setConnWriteDeadline(conn net.Conn) time.Time {
d.mutex.Lock()
deadline := d.value
d.wconn = conn
d.wconn.SetWriteDeadline(deadline)
d.mutex.Unlock()
return deadline
}
func (d *connDeadline) unsetConnReadDeadline() {
d.mutex.Lock()
d.rconn = nil
d.mutex.Unlock()
}
func (d *connDeadline) unsetConnWriteDeadline() {
d.mutex.Lock()
d.wconn = nil
d.mutex.Unlock()
}
|