Scott Baker | 2d89798 | 2019-09-24 11:50:08 -0700 | [diff] [blame^] | 1 | /* |
| 2 | Package sarama is a pure Go client library for dealing with Apache Kafka (versions 0.8 and later). It includes a high-level |
| 3 | API for easily producing and consuming messages, and a low-level API for controlling bytes on the wire when the high-level |
| 4 | API is insufficient. Usage examples for the high-level APIs are provided inline with their full documentation. |
| 5 | |
| 6 | To produce messages, use either the AsyncProducer or the SyncProducer. The AsyncProducer accepts messages on a channel |
| 7 | and produces them asynchronously in the background as efficiently as possible; it is preferred in most cases. |
| 8 | The SyncProducer provides a method which will block until Kafka acknowledges the message as produced. This can be |
| 9 | useful but comes with two caveats: it will generally be less efficient, and the actual durability guarantees |
| 10 | depend on the configured value of `Producer.RequiredAcks`. There are configurations where a message acknowledged by the |
| 11 | SyncProducer can still sometimes be lost. |
| 12 | |
| 13 | To consume messages, use the Consumer. Note that Sarama's Consumer implementation does not currently support automatic |
| 14 | consumer-group rebalancing and offset tracking. For Zookeeper-based tracking (Kafka 0.8.2 and earlier), the |
| 15 | https://github.com/wvanbergen/kafka library builds on Sarama to add this support. For Kafka-based tracking (Kafka 0.9 |
| 16 | and later), the https://github.com/bsm/sarama-cluster library builds on Sarama to add this support. |
| 17 | |
| 18 | For lower-level needs, the Broker and Request/Response objects permit precise control over each connection |
| 19 | and message sent on the wire; the Client provides higher-level metadata management that is shared between |
| 20 | the producers and the consumer. The Request/Response objects and properties are mostly undocumented, as they line up |
| 21 | exactly with the protocol fields documented by Kafka at |
| 22 | https://cwiki.apache.org/confluence/display/KAFKA/A+Guide+To+The+Kafka+Protocol |
| 23 | |
| 24 | Metrics are exposed through https://github.com/rcrowley/go-metrics library in a local registry. |
| 25 | |
| 26 | Broker related metrics: |
| 27 | |
| 28 | +----------------------------------------------+------------+---------------------------------------------------------------+ |
| 29 | | Name | Type | Description | |
| 30 | +----------------------------------------------+------------+---------------------------------------------------------------+ |
| 31 | | incoming-byte-rate | meter | Bytes/second read off all brokers | |
| 32 | | incoming-byte-rate-for-broker-<broker-id> | meter | Bytes/second read off a given broker | |
| 33 | | outgoing-byte-rate | meter | Bytes/second written off all brokers | |
| 34 | | outgoing-byte-rate-for-broker-<broker-id> | meter | Bytes/second written off a given broker | |
| 35 | | request-rate | meter | Requests/second sent to all brokers | |
| 36 | | request-rate-for-broker-<broker-id> | meter | Requests/second sent to a given broker | |
| 37 | | request-size | histogram | Distribution of the request size in bytes for all brokers | |
| 38 | | request-size-for-broker-<broker-id> | histogram | Distribution of the request size in bytes for a given broker | |
| 39 | | request-latency-in-ms | histogram | Distribution of the request latency in ms for all brokers | |
| 40 | | request-latency-in-ms-for-broker-<broker-id> | histogram | Distribution of the request latency in ms for a given broker | |
| 41 | | response-rate | meter | Responses/second received from all brokers | |
| 42 | | response-rate-for-broker-<broker-id> | meter | Responses/second received from a given broker | |
| 43 | | response-size | histogram | Distribution of the response size in bytes for all brokers | |
| 44 | | response-size-for-broker-<broker-id> | histogram | Distribution of the response size in bytes for a given broker | |
| 45 | +----------------------------------------------+------------+---------------------------------------------------------------+ |
| 46 | |
| 47 | Note that we do not gather specific metrics for seed brokers but they are part of the "all brokers" metrics. |
| 48 | |
| 49 | Producer related metrics: |
| 50 | |
| 51 | +-------------------------------------------+------------+--------------------------------------------------------------------------------------+ |
| 52 | | Name | Type | Description | |
| 53 | +-------------------------------------------+------------+--------------------------------------------------------------------------------------+ |
| 54 | | batch-size | histogram | Distribution of the number of bytes sent per partition per request for all topics | |
| 55 | | batch-size-for-topic-<topic> | histogram | Distribution of the number of bytes sent per partition per request for a given topic | |
| 56 | | record-send-rate | meter | Records/second sent to all topics | |
| 57 | | record-send-rate-for-topic-<topic> | meter | Records/second sent to a given topic | |
| 58 | | records-per-request | histogram | Distribution of the number of records sent per request for all topics | |
| 59 | | records-per-request-for-topic-<topic> | histogram | Distribution of the number of records sent per request for a given topic | |
| 60 | | compression-ratio | histogram | Distribution of the compression ratio times 100 of record batches for all topics | |
| 61 | | compression-ratio-for-topic-<topic> | histogram | Distribution of the compression ratio times 100 of record batches for a given topic | |
| 62 | +-------------------------------------------+------------+--------------------------------------------------------------------------------------+ |
| 63 | |
| 64 | */ |
| 65 | package sarama |
| 66 | |
| 67 | import ( |
| 68 | "io/ioutil" |
| 69 | "log" |
| 70 | ) |
| 71 | |
| 72 | // Logger is the instance of a StdLogger interface that Sarama writes connection |
| 73 | // management events to. By default it is set to discard all log messages via ioutil.Discard, |
| 74 | // but you can set it to redirect wherever you want. |
| 75 | var Logger StdLogger = log.New(ioutil.Discard, "[Sarama] ", log.LstdFlags) |
| 76 | |
| 77 | // StdLogger is used to log error messages. |
| 78 | type StdLogger interface { |
| 79 | Print(v ...interface{}) |
| 80 | Printf(format string, v ...interface{}) |
| 81 | Println(v ...interface{}) |
| 82 | } |
| 83 | |
| 84 | // PanicHandler is called for recovering from panics spawned internally to the library (and thus |
| 85 | // not recoverable by the caller's goroutine). Defaults to nil, which means panics are not recovered. |
| 86 | var PanicHandler func(interface{}) |
| 87 | |
| 88 | // MaxRequestSize is the maximum size (in bytes) of any request that Sarama will attempt to send. Trying |
| 89 | // to send a request larger than this will result in an PacketEncodingError. The default of 100 MiB is aligned |
| 90 | // with Kafka's default `socket.request.max.bytes`, which is the largest request the broker will attempt |
| 91 | // to process. |
| 92 | var MaxRequestSize int32 = 100 * 1024 * 1024 |
| 93 | |
| 94 | // MaxResponseSize is the maximum size (in bytes) of any response that Sarama will attempt to parse. If |
| 95 | // a broker returns a response message larger than this value, Sarama will return a PacketDecodingError to |
| 96 | // protect the client from running out of memory. Please note that brokers do not have any natural limit on |
| 97 | // the size of responses they send. In particular, they can send arbitrarily large fetch responses to consumers |
| 98 | // (see https://issues.apache.org/jira/browse/KAFKA-2063). |
| 99 | var MaxResponseSize int32 = 100 * 1024 * 1024 |