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Documentation Grafana Agent Grafana Agent Flow Reference Components loki.source.kafka

loki.source.kafka

loki.source.kafka reads messages from Kafka using a consumer group and forwards them to other loki.* components.

The component starts a new Kafka consumer group for the given arguments and fans out incoming entries to the list of receivers in forward_to.

Before using loki.source.kafka, Kafka should have at least one producer writing events to at least one topic. Follow the steps in the Kafka Quick Start to get started with Kafka.

Multiple loki.source.kafka components can be specified by giving them different labels.

Usage

river Copy

loki.source.kafka "LABEL" {
  brokers    = BROKER_LIST
  topics     = TOPIC_LIST
  forward_to = RECEIVER_LIST
}

Arguments

loki.source.kafka supports the following arguments:

assignor values can be either "range", "roundrobin", or "sticky".

Labels from the labels argument are applied to every message that the component reads.

The relabel_rules field can make use of the rules export value from a loki.relabel component to apply one or more relabeling rules to log entries before they’re forwarded to the list of receivers in forward_to.

In addition to custom labels, the following internal labels prefixed with __ are available:

• __meta_kafka_message_key
• __meta_kafka_topic
• __meta_kafka_partition
• __meta_kafka_member_id
• __meta_kafka_group_id

All labels starting with __ are removed prior to forwarding log entries. To keep these labels, relabel them using a loki.relabel component and pass its rules export to the relabel_rules argument.

Blocks

The following blocks are supported inside the definition of loki.source.kafka:

authentication block

The authentication block defines the authentication method when communicating with the Kafka event brokers.

type supports the values "none", "ssl", and "sasl". If "ssl" is used, you must set the tls_config block. If "sasl" is used, you must set the sasl_config block.

tls_config block

When min_version is not provided, the minimum acceptable TLS version is inherited from Go’s default minimum version, TLS 1.2. If min_version is provided, it must be set to one of the following strings:

• "TLS10" (TLS 1.0)
• "TLS11" (TLS 1.1)
• "TLS12" (TLS 1.2)
• "TLS13" (TLS 1.3)

sasl_config block

The sasl_config block defines the listen address and port where the listener expects Kafka messages to be sent to.

Exported fields

loki.source.kafka does not export any fields.

Component health

loki.source.kafka is only reported as unhealthy if given an invalid configuration.

Debug information

loki.source.kafka does not expose additional debug info.

Example

This example consumes Kafka events from the specified brokers and topics then forwards them to a loki.write component using the Kafka timestamp.

river Copy

loki.relabel "kafka" {
  rule {
    source_labels = ["__meta_kafka_topic"]
    target_label  = "topic"
  }
}


loki.source.kafka "local" {
  brokers                = ["localhost:9092"]
  topics                 = ["quickstart-events"]
  labels                 = {component = "loki.source.kafka"}
  forward_to             = [loki.write.local.receiver]
  use_incoming_timestamp = true
  relabel_rules          = loki.relabel.kafka.rules
}

loki.write "local" {
  endpoint {
    url = "loki:3100/api/v1/push"
  }
}