Kafka source

Configuration

Example configurations

{
  "sources": {
    "my_source_id": {
      "type": "kafka",
      "bootstrap_servers": "10.14.22.123:9092,10.14.23.332:9092",
      "group_id": "consumer-group-name",
      "topics": [
        "^(prefix1|prefix2)-.+"
      ]
    }
  }
}

[sources.my_source_id]
type = "kafka"
bootstrap_servers = "10.14.22.123:9092,10.14.23.332:9092"
group_id = "consumer-group-name"
topics = [ "^(prefix1|prefix2)-.+" ]

sources:
  my_source_id:
    type: kafka
    bootstrap_servers: 10.14.22.123:9092,10.14.23.332:9092
    group_id: consumer-group-name
    topics:
      - ^(prefix1|prefix2)-.+

{
  "sources": {
    "my_source_id": {
      "type": "kafka",
      "auto_offset_reset": "largest",
      "bootstrap_servers": "10.14.22.123:9092,10.14.23.332:9092",
      "commit_interval_ms": 5000,
      "drain_timeout_ms": 2500,
      "fetch_wait_max_ms": 100,
      "group_id": "consumer-group-name",
      "headers_key": "headers",
      "key_field": "message_key",
      "librdkafka_options": {
        "client.id": "${ENV_VAR}",
        "fetch.error.backoff.ms": "1000",
        "socket.send.buffer.bytes": "100"
      },
      "offset_key": "offset",
      "partition_key": "partition",
      "session_timeout_ms": 10000,
      "socket_timeout_ms": 60000,
      "topic_key": "topic",
      "topics": [
        "^(prefix1|prefix2)-.+"
      ]
    }
  }
}

[sources.my_source_id]
type = "kafka"
auto_offset_reset = "largest"
bootstrap_servers = "10.14.22.123:9092,10.14.23.332:9092"
commit_interval_ms = 5_000
drain_timeout_ms = 2_500
fetch_wait_max_ms = 100
group_id = "consumer-group-name"
headers_key = "headers"
key_field = "message_key"
offset_key = "offset"
partition_key = "partition"
session_timeout_ms = 10_000
socket_timeout_ms = 60_000
topic_key = "topic"
topics = [ "^(prefix1|prefix2)-.+" ]

  [sources.my_source_id.librdkafka_options]
  "client.id" = "${ENV_VAR}"
  "fetch.error.backoff.ms" = "1000"
  "socket.send.buffer.bytes" = "100"

sources:
  my_source_id:
    type: kafka
    auto_offset_reset: largest
    bootstrap_servers: 10.14.22.123:9092,10.14.23.332:9092
    commit_interval_ms: 5000
    drain_timeout_ms: 2500
    fetch_wait_max_ms: 100
    group_id: consumer-group-name
    headers_key: headers
    key_field: message_key
    librdkafka_options:
      client.id: ${ENV_VAR}
      fetch.error.backoff.ms: "1000"
      socket.send.buffer.bytes: "100"
    offset_key: offset
    partition_key: partition
    session_timeout_ms: 10000
    socket_timeout_ms: 60000
    topic_key: topic
    topics:
      - ^(prefix1|prefix2)-.+

acknowledgements

optional object

Deprecated

This field is deprecated.

Controls how acknowledgements are handled by this source.

This setting is deprecated in favor of enabling acknowledgements at the global or sink level.

Enabling or disabling acknowledgements at the source level has no effect on acknowledgement behavior.

See End-to-end Acknowledgements for more information on how event acknowledgement is handled.

acknowledgements.enabled

optional bool

Whether or not end-to-end acknowledgements are enabled for this source.

bootstrap_servers

required string literal

A comma-separated list of Kafka bootstrap servers.

These are the servers in a Kafka cluster that a client should use to bootstrap its connection to the cluster, allowing discovery of all the other hosts in the cluster.

Must be in the form of host:port, and comma-separated.

Examples

"10.14.22.123:9092,10.14.23.332:9092"

commit_interval_ms

optional uint

The frequency that the consumer offsets are committed (written) to offset storage.

Examples

default: 5000 (milliseconds)

decoding

optional object

Configures how events are decoded from raw bytes.

decoding.avro

required object

Apache Avro-specific encoder options.

Relevant when: codec = "avro"

decoding.avro.schema

required string literal

The Avro schema definition. Please note that the following [apache_avro::types::Value] variants are currently not supported:

Date
Decimal
Duration
Fixed
TimeMillis

Examples

"{ \"type\": \"record\", \"name\": \"log\", \"fields\": [{ \"name\": \"message\", \"type\": \"string\" }] }"

decoding.avro.strip_schema_id_prefix

required bool

For Avro datum encoded in Kafka messages, the bytes are prefixed with the schema ID. Set this to true to strip the schema ID prefix. According to Confluent Kafka’s document.

Option	Description
`avro`	Decodes the raw bytes as as an Apache Avro message.
`bytes`	Uses the raw bytes as-is.
`gelf`	Decodes the raw bytes as a GELF message. This codec is experimental for the following reason: The GELF specification is more strict than the actual Graylog receiver. Vector’s decoder currently adheres more strictly to the GELF spec, with the exception that some characters such as `@` are allowed in field names. Other GELF codecs such as Loki’s, use a Go SDK that is maintained by Graylog, and is much more relaxed than the GELF spec. Going forward, Vector will use that Go SDK as the reference implementation, which means the codec may continue to relax the enforcement of specification.
`json`	Decodes the raw bytes as JSON.
`native`	Decodes the raw bytes as native Protocol Buffers format. This codec is experimental.
`native_json`	Decodes the raw bytes as native JSON format. This codec is experimental.
`protobuf`	Decodes the raw bytes as protobuf.
`syslog`	Decodes the raw bytes as a Syslog message. Decodes either as the RFC 3164-style format (“old” style) or the RFC 5424-style format (“new” style, includes structured data).
`vrl`	Decodes the raw bytes as a string and passes them as input to a VRL program.

decoding.gelf

optional object

GELF-specific decoding options.

Relevant when: codec = "gelf"

decoding.gelf.lossy

optional bool

Determines whether or not to replace invalid UTF-8 sequences instead of failing.

When true, invalid UTF-8 sequences are replaced with the U+FFFD REPLACEMENT CHARACTER.

default: true

decoding.json

optional object

JSON-specific decoding options.

Relevant when: codec = "json"

decoding.json.lossy

optional bool

Determines whether or not to replace invalid UTF-8 sequences instead of failing.

When true, invalid UTF-8 sequences are replaced with the U+FFFD REPLACEMENT CHARACTER.

default: true

decoding.native_json

optional object

Vector’s native JSON-specific decoding options.

Relevant when: codec = "native_json"

decoding.native_json.lossy

optional bool

Determines whether or not to replace invalid UTF-8 sequences instead of failing.

When true, invalid UTF-8 sequences are replaced with the U+FFFD REPLACEMENT CHARACTER.

default: true

decoding.protobuf

optional object

Protobuf-specific decoding options.

Relevant when: codec = "protobuf"

decoding.protobuf.desc_file

optional string literal

Path to desc file

decoding.protobuf.message_type

optional string literal

message type. e.g package.message

decoding.syslog

optional object

Syslog-specific decoding options.

Relevant when: codec = "syslog"

decoding.syslog.lossy

optional bool

Determines whether or not to replace invalid UTF-8 sequences instead of failing.

When true, invalid UTF-8 sequences are replaced with the U+FFFD REPLACEMENT CHARACTER.

default: true

decoding.vrl

required object

VRL-specific decoding options.

Relevant when: codec = "vrl"

The Vector Remap Language (VRL) program to execute for each event. Note that the final contents of the . target will be used as the decoding result. Compilation error or use of ‘abort’ in a program will result in a decoding error.

decoding.vrl.timezone

optional string literal

The name of the timezone to apply to timestamp conversions that do not contain an explicit time zone. The time zone name may be any name in the TZ database, or local to indicate system local time.

If not set, local will be used.

Examples

"local"

"America/New_York"

"EST5EDT"

drain_timeout_ms

optional uint

Timeout to drain pending acknowledgements during shutdown or a Kafka consumer group rebalance.

When Vector shuts down or the Kafka consumer group revokes partitions from this consumer, wait a maximum of drain_timeout_ms for the source to process pending acknowledgements. Must be less than session_timeout_ms to ensure the consumer is not excluded from the group during a rebalance.

Default value is half of session_timeout_ms.

Examples

fetch_wait_max_ms

optional uint

Maximum time the broker may wait to fill the response.

Examples

default: 100 (milliseconds)

framing

optional object

Framing configuration.

Framing handles how events are separated when encoded in a raw byte form, where each event is a frame that must be prefixed, or delimited, in a way that marks where an event begins and ends within the byte stream.

framing.character_delimited

required object

Options for the character delimited decoder.

Relevant when: method = "character_delimited"

framing.character_delimited.delimiter

required uint

The character that delimits byte sequences.

framing.character_delimited.max_length

optional uint

The maximum length of the byte buffer.

This length does not include the trailing delimiter.

By default, there is no maximum length enforced. If events are malformed, this can lead to additional resource usage as events continue to be buffered in memory, and can potentially lead to memory exhaustion in extreme cases.

If there is a risk of processing malformed data, such as logs with user-controlled input, consider setting the maximum length to a reasonably large value as a safety net. This ensures that processing is not actually unbounded.

framing.method

optional string literal enum

The framing method.

Enum options

Option	Description
`bytes`	Byte frames are passed through as-is according to the underlying I/O boundaries (for example, split between messages or stream segments).
`character_delimited`	Byte frames which are delimited by a chosen character.
`length_delimited`	Byte frames which are prefixed by an unsigned big-endian 32-bit integer indicating the length.
`newline_delimited`	Byte frames which are delimited by a newline character.
`octet_counting`	Byte frames according to the octet counting format.

default: bytes

framing.newline_delimited

optional object

Options for the newline delimited decoder.

Relevant when: method = "newline_delimited"

framing.newline_delimited.max_length

optional uint

The maximum length of the byte buffer.

This length does not include the trailing delimiter.

framing.octet_counting

optional object

Options for the octet counting decoder.

Relevant when: method = "octet_counting"

framing.octet_counting.max_length

optional uint

The maximum length of the byte buffer.

group_id

required string literal

The consumer group name to be used to consume events from Kafka.

Examples

"consumer-group-name"

headers_key

optional string literal

Overrides the name of the log field used to add the headers to each event.

The value is the headers of the Kafka message itself.

By default, "headers" is used.

Examples

"headers"

default: headers

key_field

optional string literal

Overrides the name of the log field used to add the message key to each event.

The value is the message key of the Kafka message itself.

By default, "message_key" is used.

Examples

"message_key"

default: message_key

librdkafka_options

optional object

Advanced options set directly on the underlying librdkafka client.

See the librdkafka documentation for details.

librdkafka_options.*

required string literal

A librdkafka configuration option.

metrics

optional object

Metrics (beta) configuration.

metrics.topic_lag_metric

optional bool

Expose topic lag metrics for all topics and partitions. Metric names are kafka_consumer_lag.

default: false

offset_key

optional string literal

Overrides the name of the log field used to add the offset to each event.

The value is the offset of the Kafka message itself.

By default, "offset" is used.

Examples

"offset"

default: offset

partition_key

optional string literal

Overrides the name of the log field used to add the partition to each event.

The value is the partition from which the Kafka message was consumed from.

By default, "partition" is used.

Examples

"partition"

default: partition

sasl

optional object

Configuration for SASL authentication when interacting with Kafka.

sasl.enabled

optional bool

Enables SASL authentication.

Only PLAIN- and SCRAM-based mechanisms are supported when configuring SASL authentication using sasl.*. For other mechanisms, librdkafka_options.* must be used directly to configure other librdkafka-specific values. If using sasl.kerberos.* as an example, where * is service.name, principal, kinit.md, etc., then librdkafka_options.* as a result becomes librdkafka_options.sasl.kerberos.service.name, librdkafka_options.sasl.kerberos.principal, etc.

See the librdkafka documentation for details.

SASL authentication is not supported on Windows.

sasl.mechanism

optional string literal

The SASL mechanism to use.

Examples

"SCRAM-SHA-256"

"SCRAM-SHA-512"

sasl.password

optional string literal

The SASL password.

Examples

"password"

sasl.username

optional string literal

The SASL username.

Examples

"username"

session_timeout_ms

optional uint

The Kafka session timeout.

Examples

default: 10000 (milliseconds)

socket_timeout_ms

optional uint

Timeout for network requests.

Examples

default: 60000 (milliseconds)

tls

optional object

Configures the TLS options for incoming/outgoing connections.

tls.alpn_protocols

optional [string]

Sets the list of supported ALPN protocols.

Declare the supported ALPN protocols, which are used during negotiation with peer. They are prioritized in the order that they are defined.

tls.ca_file

optional string literal

Absolute path to an additional CA certificate file.

The certificate must be in the DER or PEM (X.509) format. Additionally, the certificate can be provided as an inline string in PEM format.

Examples

"/path/to/certificate_authority.crt"

tls.crt_file

optional string literal

Absolute path to a certificate file used to identify this server.

The certificate must be in DER, PEM (X.509), or PKCS#12 format. Additionally, the certificate can be provided as an inline string in PEM format.

If this is set, and is not a PKCS#12 archive, key_file must also be set.

Examples

"/path/to/host_certificate.crt"

tls.enabled

optional bool

Whether or not to require TLS for incoming or outgoing connections.

When enabled and used for incoming connections, an identity certificate is also required. See tls.crt_file for more information.

tls.key_file

optional string literal

Absolute path to a private key file used to identify this server.

The key must be in DER or PEM (PKCS#8) format. Additionally, the key can be provided as an inline string in PEM format.

Examples

"/path/to/host_certificate.key"

tls.key_pass

optional string literal

Passphrase used to unlock the encrypted key file.

This has no effect unless key_file is set.

Examples

"${KEY_PASS_ENV_VAR}"

"PassWord1"

tls.verify_certificate

optional bool

Enables certificate verification. For components that create a server, this requires that the client connections have a valid client certificate. For components that initiate requests, this validates that the upstream has a valid certificate.

If enabled, certificates must not be expired and must be issued by a trusted issuer. This verification operates in a hierarchical manner, checking that the leaf certificate (the certificate presented by the client/server) is not only valid, but that the issuer of that certificate is also valid, and so on until the verification process reaches a root certificate.

Do NOT set this to false unless you understand the risks of not verifying the validity of certificates.

tls.verify_hostname

optional bool

Enables hostname verification.

If enabled, the hostname used to connect to the remote host must be present in the TLS certificate presented by the remote host, either as the Common Name or as an entry in the Subject Alternative Name extension.

Only relevant for outgoing connections.

Do NOT set this to false unless you understand the risks of not verifying the remote hostname.

topic_key

optional string literal

Overrides the name of the log field used to add the topic to each event.

The value is the topic from which the Kafka message was consumed from.

By default, "topic" is used.

Examples

"topic"

default: topic

topics

required [string]

The Kafka topics names to read events from.

Regular expression syntax is supported if the topic begins with ^.

Array string literal

Examples

[
  "^(prefix1|prefix2)-.+",
  "topic-1",
  "topic-2"
]

Outputs

<component_id>

Default output stream of the component. Use this component’s ID as an input to downstream transforms and sinks.

Output Data

Logs

Warning

The fields shown below will be different if log namespacing is enabled. See Log Namespacing for more details

Record

An individual Kafka record

Fields

message required string literal

The raw line from the Kafka record.

Examples

53.126.150.246 - - [01/Oct/2020:11:25:58 -0400] "GET /disintermediate HTTP/2.0" 401 20308

offset required uint

The Kafka offset at the time the record was retrieved.

Examples

partition required string literal

The Kafka partition that the record came from.

Examples

partition

source_type required string literal

The name of the source type.

Examples

kafka

timestamp required timestamp

The timestamp encoded in the Kafka message or the current time if it cannot be fetched.

Examples

2020-10-10T17:07:36.452332Z

topic required string literal

The Kafka topic that the record came from.

Examples

topic

Telemetry

Metrics

link

component_discarded_events_total

counter

The number of events dropped by this component.

component_id

The Vector component ID.

component_kind

The Vector component kind.

component_type

The Vector component type.

host optional

The hostname of the system Vector is running on.

intentional

True if the events were discarded intentionally, like a filter transform, or false if due to an error.

pid optional

The process ID of the Vector instance.

component_errors_total

counter

The total number of errors encountered by this component.

component_id

The Vector component ID.

component_kind

The Vector component kind.

component_type

The Vector component type.

error_type

The type of the error

host optional

The hostname of the system Vector is running on.

pid optional

The process ID of the Vector instance.

stage

The stage within the component at which the error occurred.

component_received_bytes_total

counter

The number of raw bytes accepted by this component from source origins.

component_id

The Vector component ID.

component_kind

The Vector component kind.

component_type

The Vector component type.

container_name optional

The name of the container from which the data originated.

file optional

The file from which the data originated.

host optional

The hostname of the system Vector is running on.

mode optional

The connection mode used by the component.

peer_addr optional

The IP from which the data originated.

peer_path optional

The pathname from which the data originated.

pid optional

The process ID of the Vector instance.

pod_name optional

The name of the pod from which the data originated.

uri optional

The sanitized URI from which the data originated.

component_received_event_bytes_total

counter

The number of event bytes accepted by this component either from tagged origins like file and uri, or cumulatively from other origins.

component_id

The Vector component ID.

component_kind

The Vector component kind.

component_type

The Vector component type.

container_name optional

The name of the container from which the data originated.

file optional

The file from which the data originated.

host optional

The hostname of the system Vector is running on.

mode optional

The connection mode used by the component.

peer_addr optional

The IP from which the data originated.

peer_path optional

The pathname from which the data originated.

pid optional

The process ID of the Vector instance.

pod_name optional

The name of the pod from which the data originated.

uri optional

The sanitized URI from which the data originated.

component_received_events_count

histogram

A histogram of the number of events passed in each internal batch in Vector’s internal topology.

Note that this is separate than sink-level batching. It is mostly useful for low level debugging performance issues in Vector due to small internal batches.

component_id

The Vector component ID.

component_kind

The Vector component kind.

component_type

The Vector component type.

container_name optional

The name of the container from which the data originated.

file optional

The file from which the data originated.

host optional

The hostname of the system Vector is running on.

mode optional

The connection mode used by the component.

peer_addr optional

The IP from which the data originated.

peer_path optional

The pathname from which the data originated.

pid optional

The process ID of the Vector instance.

pod_name optional

The name of the pod from which the data originated.

uri optional

The sanitized URI from which the data originated.

component_received_events_total

counter

The number of events accepted by this component either from tagged origins like file and uri, or cumulatively from other origins.

component_id

The Vector component ID.

component_kind

The Vector component kind.

component_type

The Vector component type.

container_name optional

The name of the container from which the data originated.

file optional

The file from which the data originated.

host optional

The hostname of the system Vector is running on.

mode optional

The connection mode used by the component.

peer_addr optional

The IP from which the data originated.

peer_path optional

The pathname from which the data originated.

pid optional

The process ID of the Vector instance.

pod_name optional

The name of the pod from which the data originated.

uri optional

The sanitized URI from which the data originated.

component_sent_event_bytes_total

counter

The total number of event bytes emitted by this component.

component_id

The Vector component ID.

component_kind

The Vector component kind.

component_type

The Vector component type.

host optional

The hostname of the system Vector is running on.

output optional

The specific output of the component.

pid optional

The process ID of the Vector instance.

component_sent_events_total

counter

The total number of events emitted by this component.

component_id

The Vector component ID.

component_kind

The Vector component kind.

component_type

The Vector component type.

host optional

The hostname of the system Vector is running on.

output optional

The specific output of the component.

pid optional

The process ID of the Vector instance.

kafka_consumed_messages_bytes_total

counter

Total number of message bytes (including framing) received from Kafka brokers.

component_id

The Vector component ID.

component_kind

The Vector component kind.

component_type

The Vector component type.

host optional

The hostname of the system Vector is running on.

pid optional

The process ID of the Vector instance.

kafka_consumed_messages_total

counter

Total number of messages consumed, not including ignored messages (due to offset, etc), from Kafka brokers.

component_id

The Vector component ID.

component_kind

The Vector component kind.

component_type

The Vector component type.

host optional

The hostname of the system Vector is running on.

pid optional

The process ID of the Vector instance.

kafka_consumer_lag

gauge

The Kafka consumer lag.

component_id

The Vector component ID.

component_kind

The Vector component kind.

component_type

The Vector component type.

host optional

The hostname of the system Vector is running on.

partition_id

The Kafka partition id.

pid optional

The process ID of the Vector instance.

topic_id

The Kafka topic id.

kafka_produced_messages_bytes_total

counter

Total number of message bytes (including framing, such as per-Message framing and MessageSet/batch framing) transmitted to Kafka brokers.

component_id

The Vector component ID.

component_kind

The Vector component kind.

component_type

The Vector component type.

host optional

The hostname of the system Vector is running on.

pid optional

The process ID of the Vector instance.

kafka_produced_messages_total

counter

Total number of messages transmitted (produced) to Kafka brokers.

component_id

The Vector component ID.

component_kind

The Vector component kind.

component_type

The Vector component type.

host optional

The hostname of the system Vector is running on.

pid optional

The process ID of the Vector instance.

kafka_queue_messages

gauge

Current number of messages in producer queues.

component_id

The Vector component ID.

component_kind

The Vector component kind.

component_type

The Vector component type.

host optional

The hostname of the system Vector is running on.

pid optional

The process ID of the Vector instance.

kafka_queue_messages_bytes

gauge

Current total size of messages in producer queues.

component_id

The Vector component ID.

component_kind

The Vector component kind.

component_type

The Vector component type.

host optional

The hostname of the system Vector is running on.

pid optional

The process ID of the Vector instance.

kafka_requests_bytes_total

counter

Total number of bytes transmitted to Kafka brokers.

component_id

The Vector component ID.

component_kind

The Vector component kind.

component_type

The Vector component type.

host optional

The hostname of the system Vector is running on.

pid optional

The process ID of the Vector instance.

kafka_requests_total

counter

Total number of requests sent to Kafka brokers.

component_id

The Vector component ID.

component_kind

The Vector component kind.

component_type

The Vector component type.

host optional

The hostname of the system Vector is running on.

pid optional

The process ID of the Vector instance.

kafka_responses_bytes_total

counter

Total number of bytes received from Kafka brokers.

component_id

The Vector component ID.

component_kind

The Vector component kind.

component_type

The Vector component type.

host optional

The hostname of the system Vector is running on.

pid optional

The process ID of the Vector instance.

kafka_responses_total

counter

Total number of responses received from Kafka brokers.

component_id

The Vector component ID.

component_kind

The Vector component kind.

component_type

The Vector component type.

host optional

The hostname of the system Vector is running on.

pid optional

The process ID of the Vector instance.

source_lag_time_seconds

histogram

The difference between the timestamp recorded in each event and the time when it was ingested, expressed as fractional seconds.

component_id

The Vector component ID.

component_kind

The Vector component kind.

component_type

The Vector component type.

host optional

The hostname of the system Vector is running on.

pid optional

The process ID of the Vector instance.

How it works

Azure Event Hubs

It is possible to use the kafka source and sink with Azure Event Hubs for all tiers other than the Basic tier. More details can be found here. To configure the source and sink to connect to Azure Event Hubs set the following options:

bootstrap_servers - <namespace name>.servicebus.windows.net:9093
group_id - The consumer group. Note that if the default group ($Default) is used it must be specified as $$Default to escape the $ used for environment variables.
topics - The event hub name.
sasl.enabled - Set to true.
sasl.mechanism - Set to PLAIN.
sasl.username - Set to $$ConnectionString (note the double $$).
sasl.password - Set to the connection string. See here.
tls.enabled - Set to true.
tls.ca_file - The certificate authority file.
tls.verify_certificate - Set to true.

Context

By default, the kafka source augments events with helpful context keys.

librdkafka

The kafka sink uses librdkafka under the hood. This is a battle-tested, high performance, and reliable library that facilitates communication with Kafka. As Vector produces static MUSL builds, this dependency is packaged with Vector, meaning you do not need to install it.

State

This component is stateless, meaning its behavior is consistent across each input.

Transport Layer Security (TLS)

Vector uses OpenSSL for TLS protocols due to OpenSSL’s maturity. You can enable and adjust TLS behavior via the tls.* options and/or via an OpenSSL configuration file. The file location defaults to /usr/local/ssl/openssl.cnf or can be specified with the OPENSSL_CONF environment variable.