vyvanse/vendor/github.com/Shopify/sarama/offset_manager.go

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2017-08-25 08:22:58 +00:00
package sarama
import (
"sync"
"time"
)
// Offset Manager
// OffsetManager uses Kafka to store and fetch consumed partition offsets.
type OffsetManager interface {
// ManagePartition creates a PartitionOffsetManager on the given topic/partition.
// It will return an error if this OffsetManager is already managing the given
// topic/partition.
ManagePartition(topic string, partition int32) (PartitionOffsetManager, error)
// Close stops the OffsetManager from managing offsets. It is required to call
// this function before an OffsetManager object passes out of scope, as it
// will otherwise leak memory. You must call this after all the
// PartitionOffsetManagers are closed.
Close() error
}
type offsetManager struct {
client Client
conf *Config
group string
lock sync.Mutex
poms map[string]map[int32]*partitionOffsetManager
boms map[*Broker]*brokerOffsetManager
}
// NewOffsetManagerFromClient creates a new OffsetManager from the given client.
// It is still necessary to call Close() on the underlying client when finished with the partition manager.
func NewOffsetManagerFromClient(group string, client Client) (OffsetManager, error) {
// Check that we are not dealing with a closed Client before processing any other arguments
if client.Closed() {
return nil, ErrClosedClient
}
om := &offsetManager{
client: client,
conf: client.Config(),
group: group,
poms: make(map[string]map[int32]*partitionOffsetManager),
boms: make(map[*Broker]*brokerOffsetManager),
}
return om, nil
}
func (om *offsetManager) ManagePartition(topic string, partition int32) (PartitionOffsetManager, error) {
pom, err := om.newPartitionOffsetManager(topic, partition)
if err != nil {
return nil, err
}
om.lock.Lock()
defer om.lock.Unlock()
topicManagers := om.poms[topic]
if topicManagers == nil {
topicManagers = make(map[int32]*partitionOffsetManager)
om.poms[topic] = topicManagers
}
if topicManagers[partition] != nil {
return nil, ConfigurationError("That topic/partition is already being managed")
}
topicManagers[partition] = pom
return pom, nil
}
func (om *offsetManager) Close() error {
return nil
}
func (om *offsetManager) refBrokerOffsetManager(broker *Broker) *brokerOffsetManager {
om.lock.Lock()
defer om.lock.Unlock()
bom := om.boms[broker]
if bom == nil {
bom = om.newBrokerOffsetManager(broker)
om.boms[broker] = bom
}
bom.refs++
return bom
}
func (om *offsetManager) unrefBrokerOffsetManager(bom *brokerOffsetManager) {
om.lock.Lock()
defer om.lock.Unlock()
bom.refs--
if bom.refs == 0 {
close(bom.updateSubscriptions)
if om.boms[bom.broker] == bom {
delete(om.boms, bom.broker)
}
}
}
func (om *offsetManager) abandonBroker(bom *brokerOffsetManager) {
om.lock.Lock()
defer om.lock.Unlock()
delete(om.boms, bom.broker)
}
func (om *offsetManager) abandonPartitionOffsetManager(pom *partitionOffsetManager) {
om.lock.Lock()
defer om.lock.Unlock()
delete(om.poms[pom.topic], pom.partition)
if len(om.poms[pom.topic]) == 0 {
delete(om.poms, pom.topic)
}
}
// Partition Offset Manager
// PartitionOffsetManager uses Kafka to store and fetch consumed partition offsets. You MUST call Close()
// on a partition offset manager to avoid leaks, it will not be garbage-collected automatically when it passes
// out of scope.
type PartitionOffsetManager interface {
// NextOffset returns the next offset that should be consumed for the managed
// partition, accompanied by metadata which can be used to reconstruct the state
// of the partition consumer when it resumes. NextOffset() will return
// `config.Consumer.Offsets.Initial` and an empty metadata string if no offset
// was committed for this partition yet.
NextOffset() (int64, string)
// MarkOffset marks the provided offset, alongside a metadata string
// that represents the state of the partition consumer at that point in time. The
// metadata string can be used by another consumer to restore that state, so it
// can resume consumption.
//
// To follow upstream conventions, you are expected to mark the offset of the
// next message to read, not the last message read. Thus, when calling `MarkOffset`
// you should typically add one to the offset of the last consumed message.
//
// Note: calling MarkOffset does not necessarily commit the offset to the backend
// store immediately for efficiency reasons, and it may never be committed if
// your application crashes. This means that you may end up processing the same
// message twice, and your processing should ideally be idempotent.
MarkOffset(offset int64, metadata string)
// Errors returns a read channel of errors that occur during offset management, if
// enabled. By default, errors are logged and not returned over this channel. If
// you want to implement any custom error handling, set your config's
// Consumer.Return.Errors setting to true, and read from this channel.
Errors() <-chan *ConsumerError
// AsyncClose initiates a shutdown of the PartitionOffsetManager. This method will
// return immediately, after which you should wait until the 'errors' channel has
// been drained and closed. It is required to call this function, or Close before
// a consumer object passes out of scope, as it will otherwise leak memory. You
// must call this before calling Close on the underlying client.
AsyncClose()
// Close stops the PartitionOffsetManager from managing offsets. It is required to
// call this function (or AsyncClose) before a PartitionOffsetManager object
// passes out of scope, as it will otherwise leak memory. You must call this
// before calling Close on the underlying client.
Close() error
}
type partitionOffsetManager struct {
parent *offsetManager
topic string
partition int32
lock sync.Mutex
offset int64
metadata string
dirty bool
clean sync.Cond
broker *brokerOffsetManager
errors chan *ConsumerError
rebalance chan none
dying chan none
}
func (om *offsetManager) newPartitionOffsetManager(topic string, partition int32) (*partitionOffsetManager, error) {
pom := &partitionOffsetManager{
parent: om,
topic: topic,
partition: partition,
errors: make(chan *ConsumerError, om.conf.ChannelBufferSize),
rebalance: make(chan none, 1),
dying: make(chan none),
}
pom.clean.L = &pom.lock
if err := pom.selectBroker(); err != nil {
return nil, err
}
if err := pom.fetchInitialOffset(om.conf.Metadata.Retry.Max); err != nil {
return nil, err
}
pom.broker.updateSubscriptions <- pom
go withRecover(pom.mainLoop)
return pom, nil
}
func (pom *partitionOffsetManager) mainLoop() {
for {
select {
case <-pom.rebalance:
if err := pom.selectBroker(); err != nil {
pom.handleError(err)
pom.rebalance <- none{}
} else {
pom.broker.updateSubscriptions <- pom
}
case <-pom.dying:
if pom.broker != nil {
select {
case <-pom.rebalance:
case pom.broker.updateSubscriptions <- pom:
}
pom.parent.unrefBrokerOffsetManager(pom.broker)
}
pom.parent.abandonPartitionOffsetManager(pom)
close(pom.errors)
return
}
}
}
func (pom *partitionOffsetManager) selectBroker() error {
if pom.broker != nil {
pom.parent.unrefBrokerOffsetManager(pom.broker)
pom.broker = nil
}
var broker *Broker
var err error
if err = pom.parent.client.RefreshCoordinator(pom.parent.group); err != nil {
return err
}
if broker, err = pom.parent.client.Coordinator(pom.parent.group); err != nil {
return err
}
pom.broker = pom.parent.refBrokerOffsetManager(broker)
return nil
}
func (pom *partitionOffsetManager) fetchInitialOffset(retries int) error {
request := new(OffsetFetchRequest)
request.Version = 1
request.ConsumerGroup = pom.parent.group
request.AddPartition(pom.topic, pom.partition)
response, err := pom.broker.broker.FetchOffset(request)
if err != nil {
return err
}
block := response.GetBlock(pom.topic, pom.partition)
if block == nil {
return ErrIncompleteResponse
}
switch block.Err {
case ErrNoError:
pom.offset = block.Offset
pom.metadata = block.Metadata
return nil
case ErrNotCoordinatorForConsumer:
if retries <= 0 {
return block.Err
}
if err := pom.selectBroker(); err != nil {
return err
}
return pom.fetchInitialOffset(retries - 1)
case ErrOffsetsLoadInProgress:
if retries <= 0 {
return block.Err
}
time.Sleep(pom.parent.conf.Metadata.Retry.Backoff)
return pom.fetchInitialOffset(retries - 1)
default:
return block.Err
}
}
func (pom *partitionOffsetManager) handleError(err error) {
cErr := &ConsumerError{
Topic: pom.topic,
Partition: pom.partition,
Err: err,
}
if pom.parent.conf.Consumer.Return.Errors {
pom.errors <- cErr
} else {
Logger.Println(cErr)
}
}
func (pom *partitionOffsetManager) Errors() <-chan *ConsumerError {
return pom.errors
}
func (pom *partitionOffsetManager) MarkOffset(offset int64, metadata string) {
pom.lock.Lock()
defer pom.lock.Unlock()
if offset > pom.offset {
pom.offset = offset
pom.metadata = metadata
pom.dirty = true
}
}
func (pom *partitionOffsetManager) updateCommitted(offset int64, metadata string) {
pom.lock.Lock()
defer pom.lock.Unlock()
if pom.offset == offset && pom.metadata == metadata {
pom.dirty = false
pom.clean.Signal()
}
}
func (pom *partitionOffsetManager) NextOffset() (int64, string) {
pom.lock.Lock()
defer pom.lock.Unlock()
if pom.offset >= 0 {
return pom.offset, pom.metadata
}
return pom.parent.conf.Consumer.Offsets.Initial, ""
}
func (pom *partitionOffsetManager) AsyncClose() {
go func() {
pom.lock.Lock()
defer pom.lock.Unlock()
for pom.dirty {
pom.clean.Wait()
}
close(pom.dying)
}()
}
func (pom *partitionOffsetManager) Close() error {
pom.AsyncClose()
var errors ConsumerErrors
for err := range pom.errors {
errors = append(errors, err)
}
if len(errors) > 0 {
return errors
}
return nil
}
// Broker Offset Manager
type brokerOffsetManager struct {
parent *offsetManager
broker *Broker
timer *time.Ticker
updateSubscriptions chan *partitionOffsetManager
subscriptions map[*partitionOffsetManager]none
refs int
}
func (om *offsetManager) newBrokerOffsetManager(broker *Broker) *brokerOffsetManager {
bom := &brokerOffsetManager{
parent: om,
broker: broker,
timer: time.NewTicker(om.conf.Consumer.Offsets.CommitInterval),
updateSubscriptions: make(chan *partitionOffsetManager),
subscriptions: make(map[*partitionOffsetManager]none),
}
go withRecover(bom.mainLoop)
return bom
}
func (bom *brokerOffsetManager) mainLoop() {
for {
select {
case <-bom.timer.C:
if len(bom.subscriptions) > 0 {
bom.flushToBroker()
}
case s, ok := <-bom.updateSubscriptions:
if !ok {
bom.timer.Stop()
return
}
if _, ok := bom.subscriptions[s]; ok {
delete(bom.subscriptions, s)
} else {
bom.subscriptions[s] = none{}
}
}
}
}
func (bom *brokerOffsetManager) flushToBroker() {
request := bom.constructRequest()
if request == nil {
return
}
response, err := bom.broker.CommitOffset(request)
if err != nil {
bom.abort(err)
return
}
for s := range bom.subscriptions {
if request.blocks[s.topic] == nil || request.blocks[s.topic][s.partition] == nil {
continue
}
var err KError
var ok bool
if response.Errors[s.topic] == nil {
s.handleError(ErrIncompleteResponse)
delete(bom.subscriptions, s)
s.rebalance <- none{}
continue
}
if err, ok = response.Errors[s.topic][s.partition]; !ok {
s.handleError(ErrIncompleteResponse)
delete(bom.subscriptions, s)
s.rebalance <- none{}
continue
}
switch err {
case ErrNoError:
block := request.blocks[s.topic][s.partition]
s.updateCommitted(block.offset, block.metadata)
case ErrNotLeaderForPartition, ErrLeaderNotAvailable,
ErrConsumerCoordinatorNotAvailable, ErrNotCoordinatorForConsumer:
// not a critical error, we just need to redispatch
delete(bom.subscriptions, s)
s.rebalance <- none{}
case ErrOffsetMetadataTooLarge, ErrInvalidCommitOffsetSize:
// nothing we can do about this, just tell the user and carry on
s.handleError(err)
case ErrOffsetsLoadInProgress:
// nothing wrong but we didn't commit, we'll get it next time round
break
case ErrUnknownTopicOrPartition:
// let the user know *and* try redispatching - if topic-auto-create is
// enabled, redispatching should trigger a metadata request and create the
// topic; if not then re-dispatching won't help, but we've let the user
// know and it shouldn't hurt either (see https://github.com/Shopify/sarama/issues/706)
fallthrough
default:
// dunno, tell the user and try redispatching
s.handleError(err)
delete(bom.subscriptions, s)
s.rebalance <- none{}
}
}
}
func (bom *brokerOffsetManager) constructRequest() *OffsetCommitRequest {
var r *OffsetCommitRequest
var perPartitionTimestamp int64
if bom.parent.conf.Consumer.Offsets.Retention == 0 {
perPartitionTimestamp = ReceiveTime
r = &OffsetCommitRequest{
Version: 1,
ConsumerGroup: bom.parent.group,
ConsumerGroupGeneration: GroupGenerationUndefined,
}
} else {
r = &OffsetCommitRequest{
Version: 2,
RetentionTime: int64(bom.parent.conf.Consumer.Offsets.Retention / time.Millisecond),
ConsumerGroup: bom.parent.group,
ConsumerGroupGeneration: GroupGenerationUndefined,
}
}
for s := range bom.subscriptions {
s.lock.Lock()
if s.dirty {
r.AddBlock(s.topic, s.partition, s.offset, perPartitionTimestamp, s.metadata)
}
s.lock.Unlock()
}
if len(r.blocks) > 0 {
return r
}
return nil
}
func (bom *brokerOffsetManager) abort(err error) {
_ = bom.broker.Close() // we don't care about the error this might return, we already have one
bom.parent.abandonBroker(bom)
for pom := range bom.subscriptions {
pom.handleError(err)
pom.rebalance <- none{}
}
for s := range bom.updateSubscriptions {
if _, ok := bom.subscriptions[s]; !ok {
s.handleError(err)
s.rebalance <- none{}
}
}
bom.subscriptions = make(map[*partitionOffsetManager]none)
}