Scott Baker | e7144bc | 2019-10-01 14:16:47 -0700 | [diff] [blame] | 1 | package sarama |
| 2 | |
| 3 | import "sync" |
| 4 | |
| 5 | // SyncProducer publishes Kafka messages, blocking until they have been acknowledged. It routes messages to the correct |
| 6 | // broker, refreshing metadata as appropriate, and parses responses for errors. You must call Close() on a producer |
| 7 | // to avoid leaks, it may not be garbage-collected automatically when it passes out of scope. |
| 8 | // |
| 9 | // The SyncProducer comes with two caveats: it will generally be less efficient than the AsyncProducer, and the actual |
| 10 | // durability guarantee provided when a message is acknowledged depend on the configured value of `Producer.RequiredAcks`. |
| 11 | // There are configurations where a message acknowledged by the SyncProducer can still sometimes be lost. |
| 12 | // |
| 13 | // For implementation reasons, the SyncProducer requires `Producer.Return.Errors` and `Producer.Return.Successes` to |
| 14 | // be set to true in its configuration. |
| 15 | type SyncProducer interface { |
| 16 | |
| 17 | // SendMessage produces a given message, and returns only when it either has |
| 18 | // succeeded or failed to produce. It will return the partition and the offset |
| 19 | // of the produced message, or an error if the message failed to produce. |
| 20 | SendMessage(msg *ProducerMessage) (partition int32, offset int64, err error) |
| 21 | |
| 22 | // SendMessages produces a given set of messages, and returns only when all |
| 23 | // messages in the set have either succeeded or failed. Note that messages |
| 24 | // can succeed and fail individually; if some succeed and some fail, |
| 25 | // SendMessages will return an error. |
| 26 | SendMessages(msgs []*ProducerMessage) error |
| 27 | |
| 28 | // Close shuts down the producer and waits for any buffered messages to be |
| 29 | // flushed. You must call this function before a producer object passes out of |
| 30 | // scope, as it may otherwise leak memory. You must call this before calling |
| 31 | // Close on the underlying client. |
| 32 | Close() error |
| 33 | } |
| 34 | |
| 35 | type syncProducer struct { |
| 36 | producer *asyncProducer |
| 37 | wg sync.WaitGroup |
| 38 | } |
| 39 | |
| 40 | // NewSyncProducer creates a new SyncProducer using the given broker addresses and configuration. |
| 41 | func NewSyncProducer(addrs []string, config *Config) (SyncProducer, error) { |
| 42 | if config == nil { |
| 43 | config = NewConfig() |
| 44 | config.Producer.Return.Successes = true |
| 45 | } |
| 46 | |
| 47 | if err := verifyProducerConfig(config); err != nil { |
| 48 | return nil, err |
| 49 | } |
| 50 | |
| 51 | p, err := NewAsyncProducer(addrs, config) |
| 52 | if err != nil { |
| 53 | return nil, err |
| 54 | } |
| 55 | return newSyncProducerFromAsyncProducer(p.(*asyncProducer)), nil |
| 56 | } |
| 57 | |
| 58 | // NewSyncProducerFromClient creates a new SyncProducer using the given client. It is still |
| 59 | // necessary to call Close() on the underlying client when shutting down this producer. |
| 60 | func NewSyncProducerFromClient(client Client) (SyncProducer, error) { |
| 61 | if err := verifyProducerConfig(client.Config()); err != nil { |
| 62 | return nil, err |
| 63 | } |
| 64 | |
| 65 | p, err := NewAsyncProducerFromClient(client) |
| 66 | if err != nil { |
| 67 | return nil, err |
| 68 | } |
| 69 | return newSyncProducerFromAsyncProducer(p.(*asyncProducer)), nil |
| 70 | } |
| 71 | |
| 72 | func newSyncProducerFromAsyncProducer(p *asyncProducer) *syncProducer { |
| 73 | sp := &syncProducer{producer: p} |
| 74 | |
| 75 | sp.wg.Add(2) |
| 76 | go withRecover(sp.handleSuccesses) |
| 77 | go withRecover(sp.handleErrors) |
| 78 | |
| 79 | return sp |
| 80 | } |
| 81 | |
| 82 | func verifyProducerConfig(config *Config) error { |
| 83 | if !config.Producer.Return.Errors { |
| 84 | return ConfigurationError("Producer.Return.Errors must be true to be used in a SyncProducer") |
| 85 | } |
| 86 | if !config.Producer.Return.Successes { |
| 87 | return ConfigurationError("Producer.Return.Successes must be true to be used in a SyncProducer") |
| 88 | } |
| 89 | return nil |
| 90 | } |
| 91 | |
| 92 | func (sp *syncProducer) SendMessage(msg *ProducerMessage) (partition int32, offset int64, err error) { |
| 93 | expectation := make(chan *ProducerError, 1) |
| 94 | msg.expectation = expectation |
| 95 | sp.producer.Input() <- msg |
| 96 | |
| 97 | if err := <-expectation; err != nil { |
| 98 | return -1, -1, err.Err |
| 99 | } |
| 100 | |
| 101 | return msg.Partition, msg.Offset, nil |
| 102 | } |
| 103 | |
| 104 | func (sp *syncProducer) SendMessages(msgs []*ProducerMessage) error { |
| 105 | expectations := make(chan chan *ProducerError, len(msgs)) |
| 106 | go func() { |
| 107 | for _, msg := range msgs { |
| 108 | expectation := make(chan *ProducerError, 1) |
| 109 | msg.expectation = expectation |
| 110 | sp.producer.Input() <- msg |
| 111 | expectations <- expectation |
| 112 | } |
| 113 | close(expectations) |
| 114 | }() |
| 115 | |
| 116 | var errors ProducerErrors |
| 117 | for expectation := range expectations { |
| 118 | if err := <-expectation; err != nil { |
| 119 | errors = append(errors, err) |
| 120 | } |
| 121 | } |
| 122 | |
| 123 | if len(errors) > 0 { |
| 124 | return errors |
| 125 | } |
| 126 | return nil |
| 127 | } |
| 128 | |
| 129 | func (sp *syncProducer) handleSuccesses() { |
| 130 | defer sp.wg.Done() |
| 131 | for msg := range sp.producer.Successes() { |
| 132 | expectation := msg.expectation |
| 133 | expectation <- nil |
| 134 | } |
| 135 | } |
| 136 | |
| 137 | func (sp *syncProducer) handleErrors() { |
| 138 | defer sp.wg.Done() |
| 139 | for err := range sp.producer.Errors() { |
| 140 | expectation := err.Msg.expectation |
| 141 | expectation <- err |
| 142 | } |
| 143 | } |
| 144 | |
| 145 | func (sp *syncProducer) Close() error { |
| 146 | sp.producer.AsyncClose() |
| 147 | sp.wg.Wait() |
| 148 | return nil |
| 149 | } |