100 lines
7.7 KiB
Go
100 lines
7.7 KiB
Go
/*
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Package sarama is a pure Go client library for dealing with Apache Kafka (versions 0.8 and later). It includes a high-level
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API for easily producing and consuming messages, and a low-level API for controlling bytes on the wire when the high-level
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API is insufficient. Usage examples for the high-level APIs are provided inline with their full documentation.
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To produce messages, use either the AsyncProducer or the SyncProducer. The AsyncProducer accepts messages on a channel
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and produces them asynchronously in the background as efficiently as possible; it is preferred in most cases.
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The SyncProducer provides a method which will block until Kafka acknowledges the message as produced. This can be
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useful but comes with two caveats: it will generally be less efficient, and the actual durability guarantees
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depend on the configured value of `Producer.RequiredAcks`. There are configurations where a message acknowledged by the
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SyncProducer can still sometimes be lost.
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To consume messages, use the Consumer. Note that Sarama's Consumer implementation does not currently support automatic
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consumer-group rebalancing and offset tracking. For Zookeeper-based tracking (Kafka 0.8.2 and earlier), the
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https://github.com/wvanbergen/kafka library builds on Sarama to add this support. For Kafka-based tracking (Kafka 0.9
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and later), the https://github.com/bsm/sarama-cluster library builds on Sarama to add this support.
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For lower-level needs, the Broker and Request/Response objects permit precise control over each connection
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and message sent on the wire; the Client provides higher-level metadata management that is shared between
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the producers and the consumer. The Request/Response objects and properties are mostly undocumented, as they line up
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exactly with the protocol fields documented by Kafka at
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https://cwiki.apache.org/confluence/display/KAFKA/A+Guide+To+The+Kafka+Protocol
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Metrics are exposed through https://github.com/rcrowley/go-metrics library in a local registry.
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Broker related metrics:
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+----------------------------------------------+------------+---------------------------------------------------------------+
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| Name | Type | Description |
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+----------------------------------------------+------------+---------------------------------------------------------------+
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| incoming-byte-rate | meter | Bytes/second read off all brokers |
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| incoming-byte-rate-for-broker-<broker-id> | meter | Bytes/second read off a given broker |
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| outgoing-byte-rate | meter | Bytes/second written off all brokers |
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| outgoing-byte-rate-for-broker-<broker-id> | meter | Bytes/second written off a given broker |
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| request-rate | meter | Requests/second sent to all brokers |
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| request-rate-for-broker-<broker-id> | meter | Requests/second sent to a given broker |
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| request-size | histogram | Distribution of the request size in bytes for all brokers |
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| request-size-for-broker-<broker-id> | histogram | Distribution of the request size in bytes for a given broker |
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| request-latency-in-ms | histogram | Distribution of the request latency in ms for all brokers |
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| request-latency-in-ms-for-broker-<broker-id> | histogram | Distribution of the request latency in ms for a given broker |
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| response-rate | meter | Responses/second received from all brokers |
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| response-rate-for-broker-<broker-id> | meter | Responses/second received from a given broker |
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| response-size | histogram | Distribution of the response size in bytes for all brokers |
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| response-size-for-broker-<broker-id> | histogram | Distribution of the response size in bytes for a given broker |
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+----------------------------------------------+------------+---------------------------------------------------------------+
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Note that we do not gather specific metrics for seed brokers but they are part of the "all brokers" metrics.
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Producer related metrics:
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+-------------------------------------------+------------+--------------------------------------------------------------------------------------+
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| Name | Type | Description |
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+-------------------------------------------+------------+--------------------------------------------------------------------------------------+
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| batch-size | histogram | Distribution of the number of bytes sent per partition per request for all topics |
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| batch-size-for-topic-<topic> | histogram | Distribution of the number of bytes sent per partition per request for a given topic |
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| record-send-rate | meter | Records/second sent to all topics |
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| record-send-rate-for-topic-<topic> | meter | Records/second sent to a given topic |
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| records-per-request | histogram | Distribution of the number of records sent per request for all topics |
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| records-per-request-for-topic-<topic> | histogram | Distribution of the number of records sent per request for a given topic |
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| compression-ratio | histogram | Distribution of the compression ratio times 100 of record batches for all topics |
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| compression-ratio-for-topic-<topic> | histogram | Distribution of the compression ratio times 100 of record batches for a given topic |
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+-------------------------------------------+------------+--------------------------------------------------------------------------------------+
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*/
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package sarama
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import (
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"io/ioutil"
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"log"
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)
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// Logger is the instance of a StdLogger interface that Sarama writes connection
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// management events to. By default it is set to discard all log messages via ioutil.Discard,
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// but you can set it to redirect wherever you want.
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var Logger StdLogger = log.New(ioutil.Discard, "[Sarama] ", log.LstdFlags)
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// StdLogger is used to log error messages.
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type StdLogger interface {
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Print(v ...interface{})
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Printf(format string, v ...interface{})
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Println(v ...interface{})
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}
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// PanicHandler is called for recovering from panics spawned internally to the library (and thus
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// not recoverable by the caller's goroutine). Defaults to nil, which means panics are not recovered.
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var PanicHandler func(interface{})
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// MaxRequestSize is the maximum size (in bytes) of any request that Sarama will attempt to send. Trying
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// to send a request larger than this will result in an PacketEncodingError. The default of 100 MiB is aligned
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// with Kafka's default `socket.request.max.bytes`, which is the largest request the broker will attempt
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// to process.
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var MaxRequestSize int32 = 100 * 1024 * 1024
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// MaxResponseSize is the maximum size (in bytes) of any response that Sarama will attempt to parse. If
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// a broker returns a response message larger than this value, Sarama will return a PacketDecodingError to
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// protect the client from running out of memory. Please note that brokers do not have any natural limit on
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// the size of responses they send. In particular, they can send arbitrarily large fetch responses to consumers
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// (see https://issues.apache.org/jira/browse/KAFKA-2063).
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var MaxResponseSize int32 = 100 * 1024 * 1024
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