kafka-go Documentation

File: README.md Copy Chapter

kafka-go [](https://circleci.com/gh/segmentio/kafka-go) [](https://goreportcard.com/report/github.com/segmentio/kafka-go) [](https://godoc.org/github.com/segmentio/kafka-go)

Motivations Copy Chapter

We rely on both Go and Kafka a lot at Segment. Unfortunately, the state of the Go
client libraries for Kafka at the time of this writing was not ideal. The available
options were:

• sarama, which is by far the most popular
  but is quite difficult to work with. It is poorly documented, the API exposes
  low level concepts of the Kafka protocol, and it doesn't support recent Go features
  like contexts. It also passes all values as
  pointers which causes large numbers of dynamic memory allocations, more frequent
  garbage collections, and higher memory usage.

• confluent-kafka-go is a
  cgo based wrapper around librdkafka,
  which means it introduces a dependency to a C library on all Go code that uses
  the package. It has much better documentation than sarama but still lacks support
  for Go contexts.

• goka is a more recent Kafka client for Go
  which focuses on a specific usage pattern. It provides abstractions for using Kafka
  as a message passing bus between services rather than an ordered log of events, but
  this is not the typical use case of Kafka for us at Segment. The package also
  depends on sarama for all interactions with Kafka.

This is where kafka-go comes into play. It provides both low and high level
APIs for interacting with Kafka, mirroring concepts and implementing interfaces of
the Go standard library to make it easy to use and integrate with existing
software.

Note:

In order to better align with our newly adopted Code of Conduct, the kafka-go
project has renamed our default branch to main. For the full details of our
Code Of Conduct see this document.

Kafka versions Copy Chapter

kafka-go is currently tested with Kafka versions 0.10.1.0 to 2.7.1.
While it should also be compatible with later versions, newer features available
in the Kafka API may not yet be implemented in the client.

Go versions Copy Chapter

kafka-go requires Go version 1.15 or later.

Connection [](https://godoc.org/github.com/segmentio/kafka-go#Conn) Copy Chapter

The Conn type is the core of the kafka-go package. It wraps around a raw
network connection to expose a low-level API to a Kafka server.

Here are some examples showing typical use of a connection object:

// to produce messages
topic := "my-topic"
partition := 0

conn, err := kafka.DialLeader(context.Background(), "tcp", "localhost:9092", topic, partition)
if err != nil {
    log.Fatal("failed to dial leader:", err)
}

conn.SetWriteDeadline(time.Now().Add(10*time.Second))
_, err = conn.WriteMessages(
    kafka.Message{Value: []byte("one!")},
    kafka.Message{Value: []byte("two!")},
    kafka.Message{Value: []byte("three!")},
)
if err != nil {
    log.Fatal("failed to write messages:", err)
}

if err := conn.Close(); err != nil {
    log.Fatal("failed to close writer:", err)
}

// to consume messages
topic := "my-topic"
partition := 0

conn, err := kafka.DialLeader(context.Background(), "tcp", "localhost:9092", topic, partition)
if err != nil {
    log.Fatal("failed to dial leader:", err)
}

conn.SetReadDeadline(time.Now().Add(10*time.Second))
batch := conn.ReadBatch(10e3, 1e6) // fetch 10KB min, 1MB max

b := make([]byte, 10e3) // 10KB max per message
for {
    n, err := batch.Read(b)
    if err != nil {
        break
    }
    fmt.Println(string(b[:n]))
}

if err := batch.Close(); err != nil {
    log.Fatal("failed to close batch:", err)
}

if err := conn.Close(); err != nil {
    log.Fatal("failed to close connection:", err)
}

To Create Topics Copy Section

By default kafka has the auto.create.topics.enable='true' (KAFKA_CFG_AUTO_CREATE_TOPICS_ENABLE='true' in the bitnami/kafka kafka docker image). If this value is set to 'true' then topics will be created as a side effect of kafka.DialLeader like so:

// to create topics when auto.create.topics.enable='true'
conn, err := kafka.DialLeader(context.Background(), "tcp", "localhost:9092", "my-topic", 0)
if err != nil {
    panic(err.Error())
}

If auto.create.topics.enable='false' then you will need to create topics explicitly like so:

// to create topics when auto.create.topics.enable='false'
topic := "my-topic"

conn, err := kafka.Dial("tcp", "localhost:9092")
if err != nil {
    panic(err.Error())
}
defer conn.Close()

controller, err := conn.Controller()
if err != nil {
    panic(err.Error())
}
var controllerConn *kafka.Conn
controllerConn, err = kafka.Dial("tcp", net.JoinHostPort(controller.Host, strconv.Itoa(controller.Port)))
if err != nil {
    panic(err.Error())
}
defer controllerConn.Close()


topicConfigs := []kafka.TopicConfig{
    {
        Topic:             topic,
        NumPartitions:     1,
        ReplicationFactor: 1,
    },
}

err = controllerConn.CreateTopics(topicConfigs...)
if err != nil {
    panic(err.Error())
}

To Connect To Leader Via a Non-leader Connection Copy Section

// to connect to the kafka leader via an existing non-leader connection rather than using DialLeader
conn, err := kafka.Dial("tcp", "localhost:9092")
if err != nil {
    panic(err.Error())
}
defer conn.Close()
controller, err := conn.Controller()
if err != nil {
    panic(err.Error())
}
var connLeader *kafka.Conn
connLeader, err = kafka.Dial("tcp", net.JoinHostPort(controller.Host, strconv.Itoa(controller.Port)))
if err != nil {
    panic(err.Error())
}
defer connLeader.Close()

To list topics Copy Section

conn, err := kafka.Dial("tcp", "localhost:9092")
if err != nil {
    panic(err.Error())
}
defer conn.Close()

partitions, err := conn.ReadPartitions()
if err != nil {
    panic(err.Error())
}

m := map[string]struct{}{}

for _, p := range partitions {
    m[p.Topic] = struct{}{}
}
for k := range m {
    fmt.Println(k)
}

Because it is low level, the Conn type turns out to be a great building block
for higher level abstractions, like the Reader for example.

Reader [](https://godoc.org/github.com/segmentio/kafka-go#Reader) Copy Chapter

A Reader is another concept exposed by the kafka-go package, which intends
to make it simpler to implement the typical use case of consuming from a single
topic-partition pair.
A Reader also automatically handles reconnections and offset management, and
exposes an API that supports asynchronous cancellations and timeouts using Go
contexts.

Note that it is important to call Close() on a Reader when a process exits.
The kafka server needs a graceful disconnect to stop it from continuing to
attempt to send messages to the connected clients. The given example will not
call Close() if the process is terminated with SIGINT (ctrl-c at the shell) or
SIGTERM (as docker stop or a kubernetes restart does). This can result in a
delay when a new reader on the same topic connects (e.g. new process started
or new container running). Use a signal.Notify handler to close the reader on
process shutdown.

// make a new reader that consumes from topic-A, partition 0, at offset 42
r := kafka.NewReader(kafka.ReaderConfig{
    Brokers:   []string{"localhost:9092","localhost:9093", "localhost:9094"},
    Topic:     "topic-A",
    Partition: 0,
    MaxBytes:  10e6, // 10MB
})
r.SetOffset(42)

for {
    m, err := r.ReadMessage(context.Background())
    if err != nil {
        break
    }
    fmt.Printf("message at offset %d: %s = %s\n", m.Offset, string(m.Key), string(m.Value))
}

if err := r.Close(); err != nil {
    log.Fatal("failed to close reader:", err)
}

Consumer Groups Copy Section

kafka-go also supports Kafka consumer groups including broker managed offsets.
To enable consumer groups, simply specify the GroupID in the ReaderConfig.

ReadMessage automatically commits offsets when using consumer groups.

// make a new reader that consumes from topic-A
r := kafka.NewReader(kafka.ReaderConfig{
    Brokers:   []string{"localhost:9092", "localhost:9093", "localhost:9094"},
    GroupID:   "consumer-group-id",
    Topic:     "topic-A",
    MaxBytes:  10e6, // 10MB
})

for {
    m, err := r.ReadMessage(context.Background())
    if err != nil {
        break
    }
    fmt.Printf("message at topic/partition/offset %v/%v/%v: %s = %s\n", m.Topic, m.Partition, m.Offset, string(m.Key), string(m.Value))
}

if err := r.Close(); err != nil {
    log.Fatal("failed to close reader:", err)
}

There are a number of limitations when using consumer groups:

• (*Reader).SetOffset will return an error when GroupID is set
• (*Reader).Offset will always return -1 when GroupID is set
• (*Reader).Lag will always return -1 when GroupID is set
• (*Reader).ReadLag will return an error when GroupID is set
• (*Reader).Stats will return a partition of -1 when GroupID is set

Explicit Commits Copy Section

kafka-go also supports explicit commits. Instead of calling ReadMessage,
call FetchMessage followed by CommitMessages.

ctx := context.Background()
for {
    m, err := r.FetchMessage(ctx)
    if err != nil {
        break
    }
    fmt.Printf("message at topic/partition/offset %v/%v/%v: %s = %s\n", m.Topic, m.Partition, m.Offset, string(m.Key), string(m.Value))
    if err := r.CommitMessages(ctx, m); err != nil {
        log.Fatal("failed to commit messages:", err)
    }
}

When committing messages in consumer groups, the message with the highest offset
for a given topic/partition determines the value of the committed offset for
that partition. For example, if messages at offset 1, 2, and 3 of a single
partition were retrieved by call to FetchMessage, calling CommitMessages
with message offset 3 will also result in committing the messages at offsets 1
and 2 for that partition.

Managing Commits Copy Section

By default, CommitMessages will synchronously commit offsets to Kafka. For
improved performance, you can instead periodically commit offsets to Kafka
by setting CommitInterval on the ReaderConfig.

// make a new reader that consumes from topic-A
r := kafka.NewReader(kafka.ReaderConfig{
    Brokers:        []string{"localhost:9092", "localhost:9093", "localhost:9094"},
    GroupID:        "consumer-group-id",
    Topic:          "topic-A",
    MaxBytes:       10e6, // 10MB
    CommitInterval: time.Second, // flushes commits to Kafka every second
})

Writer [](https://godoc.org/github.com/segmentio/kafka-go#Writer) Copy Chapter

To produce messages to Kafka, a program may use the low-level Conn API, but
the package also provides a higher level Writer type which is more appropriate
to use in most cases as it provides additional features:

• Automatic retries and reconnections on errors.
• Configurable distribution of messages across available partitions.
• Synchronous or asynchronous writes of messages to Kafka.
• Asynchronous cancellation using contexts.
• Flushing of pending messages on close to support graceful shutdowns.
• Creation of a missing topic before publishing a message. Note! it was the default behaviour up to the version v0.4.30.

// make a writer that produces to topic-A, using the least-bytes distribution
w := &kafka.Writer{
	Addr:     kafka.TCP("localhost:9092", "localhost:9093", "localhost:9094"),
	Topic:   "topic-A",
	Balancer: &kafka.LeastBytes{},
}

err := w.WriteMessages(context.Background(),
	kafka.Message{
		Key:   []byte("Key-A"),
		Value: []byte("Hello World!"),
	},
	kafka.Message{
		Key:   []byte("Key-B"),
		Value: []byte("One!"),
	},
	kafka.Message{
		Key:   []byte("Key-C"),
		Value: []byte("Two!"),
	},
)
if err != nil {
    log.Fatal("failed to write messages:", err)
}

if err := w.Close(); err != nil {
    log.Fatal("failed to close writer:", err)
}

Missing topic creation before publication Copy Section

// Make a writer that publishes messages to topic-A.
// The topic will be created if it is missing.
w := &Writer{
    Addr:                   kafka.TCP("localhost:9092", "localhost:9093", "localhost:9094"),
    Topic:                  "topic-A",
    AllowAutoTopicCreation: true,
}

messages := []kafka.Message{
    {
        Key:   []byte("Key-A"),
        Value: []byte("Hello World!"),
    },
    {
        Key:   []byte("Key-B"),
        Value: []byte("One!"),
    },
    {
        Key:   []byte("Key-C"),
        Value: []byte("Two!"),
    },
}

var err error
const retries = 3
for i := 0; i < retries; i++ {
    ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
    defer cancel()
    
    // attempt to create topic prior to publishing the message
    err = w.WriteMessages(ctx, messages...)
    if errors.Is(err, kafka.LeaderNotAvailable) || errors.Is(err, context.DeadlineExceeded) {
        time.Sleep(time.Millisecond * 250)
        continue
    }

    if err != nil {
        log.Fatalf("unexpected error %v", err)
    }
    break
}

if err := w.Close(); err != nil {
    log.Fatal("failed to close writer:", err)
}

Writing to multiple topics Copy Section

Normally, the WriterConfig.Topic is used to initialize a single-topic writer.
By excluding that particular configuration, you are given the ability to define
the topic on a per-message basis by setting Message.Topic.

w := &kafka.Writer{
	Addr:     kafka.TCP("localhost:9092", "localhost:9093", "localhost:9094"),
    // NOTE: When Topic is not defined here, each Message must define it instead.
	Balancer: &kafka.LeastBytes{},
}

err := w.WriteMessages(context.Background(),
    // NOTE: Each Message has Topic defined, otherwise an error is returned.
	kafka.Message{
        Topic: "topic-A",
		Key:   []byte("Key-A"),
		Value: []byte("Hello World!"),
	},
	kafka.Message{
        Topic: "topic-B",
		Key:   []byte("Key-B"),
		Value: []byte("One!"),
	},
	kafka.Message{
        Topic: "topic-C",
		Key:   []byte("Key-C"),
		Value: []byte("Two!"),
	},
)
if err != nil {
    log.Fatal("failed to write messages:", err)
}

if err := w.Close(); err != nil {
    log.Fatal("failed to close writer:", err)
}

NOTE: These 2 patterns are mutually exclusive, if you set Writer.Topic,
you must not also explicitly define Message.Topic on the messages you are
writing. The opposite applies when you do not define a topic for the writer.
The Writer will return an error if it detects this ambiguity.

Compatibility with other clients Copy Section

Sarama

If you're switching from Sarama and need/want to use the same algorithm for message partitioning, you can either use
the kafka.Hash balancer or the kafka.ReferenceHash balancer:

• kafka.Hash = sarama.NewHashPartitioner
• kafka.ReferenceHash = sarama.NewReferenceHashPartitioner

The kafka.Hash and kafka.ReferenceHash balancers would route messages to the same partitions that the two
aforementioned Sarama partitioners would route them to.

w := &kafka.Writer{
	Addr:     kafka.TCP("localhost:9092", "localhost:9093", "localhost:9094"),
	Topic:    "topic-A",
	Balancer: &kafka.Hash{},
}

librdkafka and confluent-kafka-go

Use the kafka.CRC32Balancer balancer to get the same behaviour as librdkafka's
default consistent_random partition strategy.

w := &kafka.Writer{
	Addr:     kafka.TCP("localhost:9092", "localhost:9093", "localhost:9094"),
	Topic:    "topic-A",
	Balancer: kafka.CRC32Balancer{},
}

Java

Use the kafka.Murmur2Balancer balancer to get the same behaviour as the canonical
Java client's default partitioner. Note: the Java class allows you to directly specify
the partition which is not permitted.

w := &kafka.Writer{
	Addr:     kafka.TCP("localhost:9092", "localhost:9093", "localhost:9094"),
	Topic:    "topic-A",
	Balancer: kafka.Murmur2Balancer{},
}

Compression Copy Section

Compression can be enabled on the Writer by setting the Compression field:

w := &kafka.Writer{
	Addr:        kafka.TCP("localhost:9092", "localhost:9093", "localhost:9094"),
	Topic:       "topic-A",
	Compression: kafka.Snappy,
}

The Reader will by determine if the consumed messages are compressed by
examining the message attributes. However, the package(s) for all expected
codecs must be imported so that they get loaded correctly.

Note: in versions prior to 0.4 programs had to import compression packages to
install codecs and support reading compressed messages from kafka. This is no
longer the case and import of the compression packages are now no-ops.

TLS Support Copy Chapter

For a bare bones Conn type or in the Reader/Writer configs you can specify a dialer option for TLS support. If the TLS field is nil, it will not connect with TLS.
Note: Connecting to a Kafka cluster with TLS enabled without configuring TLS on the Conn/Reader/Writer can manifest in opaque io.ErrUnexpectedEOF errors.

Connection Copy Section

dialer := &kafka.Dialer{
    Timeout:   10 * time.Second,
    DualStack: true,
    TLS:       &tls.Config{...tls config...},
}

conn, err := dialer.DialContext(ctx, "tcp", "localhost:9093")

Reader Copy Section

dialer := &kafka.Dialer{
    Timeout:   10 * time.Second,
    DualStack: true,
    TLS:       &tls.Config{...tls config...},
}

r := kafka.NewReader(kafka.ReaderConfig{
    Brokers:        []string{"localhost:9092", "localhost:9093", "localhost:9094"},
    GroupID:        "consumer-group-id",
    Topic:          "topic-A",
    Dialer:         dialer,
})

Writer Copy Section

Direct Writer creation

w := kafka.Writer{
    Addr: kafka.TCP("localhost:9092", "localhost:9093", "localhost:9094"), 
    Topic:   "topic-A",
    Balancer: &kafka.Hash{},
    Transport: &kafka.Transport{
        TLS: &tls.Config{},
      },
    }

Using kafka.NewWriter

dialer := &kafka.Dialer{
    Timeout:   10 * time.Second,
    DualStack: true,
    TLS:       &tls.Config{...tls config...},
}

w := kafka.NewWriter(kafka.WriterConfig{
	Brokers: []string{"localhost:9092", "localhost:9093", "localhost:9094"},
	Topic:   "topic-A",
	Balancer: &kafka.Hash{},
	Dialer:   dialer,
})

Note that kafka.NewWriter and kafka.WriterConfig are deprecated and will be removed in a future release.

SASL Support Copy Chapter

You can specify an option on the Dialer to use SASL authentication. The Dialer can be used directly to open a Conn or it can be passed to a Reader or Writer via their respective configs. If the SASLMechanism field is nil, it will not authenticate with SASL.

SASL Authentication Types Copy Section

[Plain](https://godoc.org/github.com/segmentio/kafka-go/sasl/plain#Mechanism)

mechanism := plain.Mechanism{
    Username: "username",
    Password: "password",
}

[SCRAM](https://godoc.org/github.com/segmentio/kafka-go/sasl/scram#Mechanism)

mechanism, err := scram.Mechanism(scram.SHA512, "username", "password")
if err != nil {
    panic(err)
}

Connection Copy Section

mechanism, err := scram.Mechanism(scram.SHA512, "username", "password")
if err != nil {
    panic(err)
}

dialer := &kafka.Dialer{
    Timeout:       10 * time.Second,
    DualStack:     true,
    SASLMechanism: mechanism,
}

conn, err := dialer.DialContext(ctx, "tcp", "localhost:9093")

Reader Copy Section

mechanism, err := scram.Mechanism(scram.SHA512, "username", "password")
if err != nil {
    panic(err)
}

dialer := &kafka.Dialer{
    Timeout:       10 * time.Second,
    DualStack:     true,
    SASLMechanism: mechanism,
}

r := kafka.NewReader(kafka.ReaderConfig{
    Brokers:        []string{"localhost:9092","localhost:9093", "localhost:9094"},
    GroupID:        "consumer-group-id",
    Topic:          "topic-A",
    Dialer:         dialer,
})

Writer Copy Section

mechanism, err := scram.Mechanism(scram.SHA512, "username", "password")
if err != nil {
    panic(err)
}

// Transports are responsible for managing connection pools and other resources,
// it's generally best to create a few of these and share them across your
// application.
sharedTransport := &kafka.Transport{
    SASL: mechanism,
}

w := kafka.Writer{
	Addr:      kafka.TCP("localhost:9092", "localhost:9093", "localhost:9094"),
	Topic:     "topic-A",
	Balancer:  &kafka.Hash{},
	Transport: sharedTransport,
}

Client Copy Section

mechanism, err := scram.Mechanism(scram.SHA512, "username", "password")
if err != nil {
    panic(err)
}

// Transports are responsible for managing connection pools and other resources,
// it's generally best to create a few of these and share them across your
// application.
sharedTransport := &kafka.Transport{
    SASL: mechanism,
}

client := &kafka.Client{
    Addr:      kafka.TCP("localhost:9092", "localhost:9093", "localhost:9094"),
    Timeout:   10 * time.Second,
    Transport: sharedTransport,
}

Reading all messages within a time range

startTime := time.Now().Add(-time.Hour)
endTime := time.Now()
batchSize := int(10e6) // 10MB

r := kafka.NewReader(kafka.ReaderConfig{
    Brokers:   []string{"localhost:9092", "localhost:9093", "localhost:9094"},
    Topic:     "my-topic1",
    Partition: 0,
    MaxBytes:  batchSize,
})

r.SetOffsetAt(context.Background(), startTime)

for {
    m, err := r.ReadMessage(context.Background())

    if err != nil {
        break
    }
    if m.Time.After(endTime) {
        break
    }
    // TODO: process message
    fmt.Printf("message at offset %d: %s = %s\n", m.Offset, string(m.Key), string(m.Value))
}

if err := r.Close(); err != nil {
    log.Fatal("failed to close reader:", err)
}

Logging Copy Chapter

For visiblity into the operations of the Reader/Writer types, configure a logger on creation.

Reader Copy Section

func logf(msg string, a ...interface{}) {
	fmt.Printf(msg, a...)
	fmt.Println()
}

r := kafka.NewReader(kafka.ReaderConfig{
	Brokers:     []string{"localhost:9092", "localhost:9093", "localhost:9094"},
	Topic:       "my-topic1",
	Partition:   0,
	Logger:      kafka.LoggerFunc(logf),
	ErrorLogger: kafka.LoggerFunc(logf),
})

Writer Copy Section

func logf(msg string, a ...interface{}) {
	fmt.Printf(msg, a...)
	fmt.Println()
}

w := &kafka.Writer{
	Addr:        kafka.TCP("localhost:9092"),
	Topic:       "topic",
	Logger:      kafka.LoggerFunc(logf),
	ErrorLogger: kafka.LoggerFunc(logf),
}

Testing Copy Chapter

Subtle behavior changes in later Kafka versions have caused some historical tests to break, if you are running against Kafka 2.3.1 or later, exporting the KAFKA_SKIP_NETTEST=1 environment variables will skip those tests.

Run Kafka locally in docker

docker-compose up -d

Run tests

KAFKA_VERSION=2.3.1 \
  KAFKA_SKIP_NETTEST=1 \
  go test -race ./...

(or) to clean up the cached test results and run tests:

go clean -cache && make test

File: compress/snappy/go-xerial-snappy/README.md Copy Chapter

go-xerial-snappy

Xerial-compatible Snappy framing support for golang.

Packages using Xerial for snappy encoding use a framing format incompatible with
basically everything else in existence. This package wraps Go's built-in snappy
package to support it.

Apps that use this format include Apache Kafka (see
https://github.com/dpkp/kafka-python/issues/126#issuecomment-35478921 for
details).

File: docker_compose_versions/README.md Copy Chapter

Bitnami Kafka

This document outlines how to create a docker-compose file for a specific Bitnami Kafka version.

Steps to create docker-compose Copy Chapter

• Refer to docker-hub Bitnami Kafka tags and sort by NEWEST to locate the image preferred, for example: 2.7.0
• There is documentation in the (main branch)[https://github.com/bitnami/containers/blob/main/bitnami/kafka/README.md] for environment config setup information. Refer to the Notable Changes section.
• Sometimes there is a need to understand how the set up is being done. To locate the appropriate Kafka release in the repo bitnami/containers, go through the kafka commit history.
• Once a commit is located, Refer to README.md, Dockerfile, entrypoint and various init scripts to understand the environment variables to config server.properties mapping conventions. Alternatively, you can spin up the required Kafka image and refer the mapping inside the container.
• Ensure you follow the environment variable conventions in your docker-compose. Without proper environment variables, the Kafka cluster cannot start or can start with undesired configs. For example, Since Kafka version 2.3, all server.properties docker-compose environment configs start with KAFKA_CFG_<config_with_underscore>
• Older versions of Bitnami Kafka have different conventions and limited docker-compose environment variables exposed for configs needed in server.properties

In kafka-go, for all the test cases to succeed, Kafka cluster should have following server.properties along with a relevant kafka_jaas.conf mentioned in the KAFKA_OPTS. Goal is to ensure that the docker-compose file generates below server.properties.

server.properties

advertised.host.name=localhost
advertised.listeners=PLAINTEXT://localhost:9092,SASL_PLAINTEXT://localhost:9093
advertised.port=9092
auto.create.topics.enable=true
broker.id=1
delete.topic.enable=true
group.initial.rebalance.delay.ms=0
listeners=PLAINTEXT://:9092,SASL_PLAINTEXT://:9093
log.dirs=/kafka/kafka-logs-1d5951569d78
log.retention.check.interval.ms=300000
log.retention.hours=168
log.segment.bytes=1073741824
message.max.bytes=200000000
num.io.threads=8
num.network.threads=3
num.partitions=1
num.recovery.threads.per.data.dir=1
offsets.topic.replication.factor=1
port=9092
sasl.enabled.mechanisms=PLAIN,SCRAM-SHA-256,SCRAM-SHA-512
socket.receive.buffer.bytes=102400
socket.request.max.bytes=104857600
socket.send.buffer.bytes=102400
transaction.state.log.min.isr=1
transaction.state.log.replication.factor=1
zookeeper.connect=zookeeper:2181
zookeeper.connection.timeout.ms=6000

run docker-compose and test cases Copy Chapter

run docker-compose

# docker-compose -f ./docker_compose_versions/docker-compose-<kafka_version>.yml up -d

run test cases

# go clean -cache; KAFKA_SKIP_NETTEST=1 KAFKA_VERSION=<a.b.c> go test -race -cover ./...;

Various Bitnami Kafka version issues observed in circleci Copy Chapter

Kafka v101, v111, v201, v211 and v221 Copy Section

In kafka-go repo, all the tests require sasl.enabled.mechanisms as PLAIN,SCRAM-SHA-256,SCRAM-SHA-512 for the Kafka cluster.

It has been observed for Kafka v101, v111, v201, v211 and v221 which are used in the circleci for build have issues with SCRAM.

There is no way to override the config sasl.enabled.mechanisms causing Kafka cluster to start up as PLAIN.

There has been some attempts made to override sasl.enabled.mechanisms

• Modified entrypoint in docker-compose to append the server.properties with relevant configs sasl.enabled.mechanisms before running entrypoint.sh. This resulted in failures for Kafka v101, v111, v201, v211 and v221. Once Kafka server starts, server.properties gets appended with default value of sasl.enabled.mechanisms there by cluster to start with out PLAIN,SCRAM-SHA-256,SCRAM-SHA-512
• Mounted a docker-compose volume for server.propeties. However, This also resulted in failures for Kafka v101, v111, v201, v211 and v221. Once Kafka server starts, server.properties gets appended with default value of sasl.enabled.mechanisms there by cluster to start with out PLAIN,SCRAM-SHA-256,SCRAM-SHA-512

NOTE:

• Kafka v101, v111, v201, v211 and v221 have no docker-compose files since we need SCRAM for kafka-go test cases to succeed.
• There is no Bitnami Kafka image for v222 hence testing has been performed on v221

Kafka v231 Copy Section

In Bitnami Kafka v2.3, all server.properties docker-compose environment configs start with KAFKA_CFG_<config_with_underscore>. However, it is not picking the custom populated kafka_jaas.conf.

After a lot of debugging, it has been noticed that there aren't enough privileges to create the kafka_jaas.conf. Hence the environment variables below need to be added in docker-compose to generate the kafka_jaas.conf. This issue is not noticed after kafka v2.3

KAFKA_INTER_BROKER_USER: adminplain
KAFKA_INTER_BROKER_PASSWORD: admin-secret
KAFKA_BROKER_USER: adminplain
KAFKA_BROKER_PASSWORD: admin-secret

There is a docker-compose file docker-compose-231.yml in the folder kafka-go/docker_compose_versions for reference.

References Copy Chapter

For user reference, please find the some of the older kafka versions commits from the kafka commit history. For Kafka versions with no commit history, data is populated with the latest version available for the tag.

Kafka v010: docker-compose reference: `kafka-go/docker_compose_versions/docker-compose-010.yml` Copy Section

• tag
• kafka commit

Kafka v011: docker-compose reference: `kafka-go/docker_compose_versions/docker-compose-011.yml` Copy Section

• tag
• kafka commit

Kafka v101: docker-compose reference: N/A Copy Section

• tag
• kafka commit

Kafka v111: docker-compose reference: N/A Copy Section

• tag
• kafka commit

Kafka v201: docker-compose reference: N/A Copy Section

• tag
• kafka commit

Kafka v211: docker-compose reference: N/A Copy Section

• tag
• kafka commit

Kafka v221: docker-compose reference: N/A Copy Section

• tag
• kafka commit

Kafka v231: docker-compose reference: `kafka-go/docker_compose_versions/docker-compose-231.yml` Copy Section

• tag
• kafka commit

File: sasl/aws_msk_iam_v2/README.md Copy Chapter

AWS MSK IAM V2

This extension provides a capability to get authenticated with AWS Managed Apache Kafka
through AWS IAM.

How to use Copy Chapter

This module is an extension for MSK users and thus this is isolated from kafka-go module.
You can add this module to your dependency by running the command below.

go get github.com/segmentio/kafka-go/sasl/aws_msk_iam_v2

Please find the sample code in example_test.go, you can use the Mechanism for SASL authentication of Reader and Writer.