Kafka Franz

Last updated: 7 minutes read.

Common

# Common config fields, showing default values
output:
  label: ""
  kafka_franz:
    seed_brokers: [] # No default (required)
    topic: "" # No default (required)
    key: "" # No default (optional)
    partition: ${! meta("partition") } # No default (optional)
    metadata:
      include_prefixes: []
      include_patterns: []
    max_in_flight: 10
    batching:
      count: 0
      byte_size: 0
      period: ""
      check: ""

Advanced

# All config fields, showing default values
output:
  label: ""
  kafka_franz:
    seed_brokers: [] # No default (required)
    topic: "" # No default (required)
    key: "" # No default (optional)
    partitioner: "" # No default (optional)
    partition: ${! meta("partition") } # No default (optional)
    client_id: tyk
    rack_id: ""
    idempotent_write: true
    metadata:
      include_prefixes: []
      include_patterns: []
    max_in_flight: 10
    timeout: 10s
    batching:
      count: 0
      byte_size: 0
      period: ""
      check: ""
      processors: [] # No default (optional)
    max_message_bytes: 1MB
    compression: "" # No default (optional)
    tls:
      enabled: false
      skip_cert_verify: false
      enable_renegotiation: false
      root_cas: ""
      root_cas_file: ""
      client_certs: []
    sasl: [] # No default (optional)

Writes a batch of messages to Kafka brokers and waits for acknowledgment before propagating it back to the input.

This output often out-performs the traditional kafka output as well as providing more useful logs and error messages.

Fields

seed_brokers

A list of broker addresses to connect to in order to establish connections. If an item of the list contains commas it will be expanded into multiple addresses.

Type: array

# Examples

seed_brokers:
  - localhost:9092

seed_brokers:
  - foo:9092
  - bar:9092

seed_brokers:
  - foo:9092,bar:9092

topic

A topic to write messages to. This field supports interpolation functions.

Type: string

key

An optional key to populate for each message. This field supports interpolation functions.

Type: string

partitioner

Override the default murmur2 hashing partitioner.

Type: string

Option Summary
least_backup Chooses the least backed up partition (the partition with the fewest amount of buffered records). Partitions are selected per batch.
manual Manually select a partition for each message, requires the field partition to be specified.
murmur2_hash Kafka’s default hash algorithm that uses a 32-bit murmur2 hash of the key to compute which partition the record will be on.
round_robin Round-robin’s messages through all available partitions. This algorithm has lower throughput and causes higher CPU load on brokers, but can be useful if you want to ensure an even distribution of records to partitions.

partition

An optional explicit partition to set for each message. This field is only relevant when the partitioner is set to manual. The provided interpolation string must be a valid integer. This field supports interpolation functions.

Type: string

# Examples

partition: ${! meta("partition") }

client_id

An identifier for the client connection.

Type: string
Default: "tyk"

rack_id

A rack identifier for this client.

Type: string
Default: ""

idempotent_write

Enable the idempotent write producer option. This requires the IDEMPOTENT_WRITE permission on CLUSTER and can be disabled if this permission is not available.

Type: bool
Default: true

metadata

Determine which (if any) metadata values should be added to messages as headers.

Type: object

metadata.include_prefixes

Provide a list of explicit metadata key prefixes to match against.

Type: array
Default: []

# Examples

include_prefixes:
  - foo_
  - bar_

include_prefixes:
  - kafka_

include_prefixes:
  - content-

metadata.include_patterns

Provide a list of explicit metadata key regular expression (re2) patterns to match against.

Type: array
Default: []

# Examples

include_patterns:
  - .*

include_patterns:
  - _timestamp_unix$

max_in_flight

The maximum number of batches to be sending in parallel at any given time.

Type: int
Default: 10

timeout

The maximum period of time to wait for message sends before abandoning the request and retrying

Type: string
Default: "10s"

batching

Allows you to configure a batching policy.

Type: object

# Examples

batching:
  byte_size: 5000
  count: 0
  period: 1s

batching:
  count: 10
  period: 1s

batching:
  check: this.contains("END BATCH")
  count: 0
  period: 1m

batching.count

A number of messages at which the batch should be flushed. If 0 disables count based batching.

Type: int
Default: 0

batching.byte_size

An amount of bytes at which the batch should be flushed. If 0 disables size based batching.

Type: int
Default: 0

batching.period

A period in which an incomplete batch should be flushed regardless of its size.

Type: string
Default: ""

# Examples

period: 1s

period: 1m

period: 500ms

batching.check

A Bloblang query that should return a boolean value indicating whether a message should end a batch.

Type: string
Default: ""

# Examples

check: this.type == "end_of_transaction"

batching.processors

A list of processors to apply to a batch as it is flushed. This allows you to aggregate and archive the batch however you see fit. Please note that all resulting messages are flushed as a single batch, therefore splitting the batch into smaller batches using these processors is a no-op.

Type: array

# Examples

processors:
  - archive:
      format: concatenate

processors:
  - archive:
      format: lines

processors:
  - archive:
      format: json_array

max_message_bytes

The maximum space in bytes than an individual message may take, messages larger than this value will be rejected. This field corresponds to Kafka’s max.message.bytes.

Type: string
Default: "1MB"

# Examples

max_message_bytes: 100MB

max_message_bytes: 50mib

compression

Optionally set an explicit compression type. The default preference is to use snappy when the broker supports it, and fall back to none if not.

Type: string
Options: lz4, snappy, gzip, none, zstd.

tls

Custom TLS settings can be used to override system defaults.

Type: object

tls.enabled

Whether custom TLS settings are enabled.

Type: bool
Default: false

tls.skip_cert_verify

Whether to skip server side certificate verification.

Type: bool
Default: false

tls.enable_renegotiation

Whether to allow the remote server to repeatedly request renegotiation. Enable this option if you’re seeing the error message local error: tls: no renegotiation.

Type: bool
Default: false

tls.root_cas

An optional root certificate authority to use. This is a string, representing a certificate chain from the parent trusted root certificate, to possible intermediate signing certificates, to the host certificate.

Type: string
Default: ""

# Examples

root_cas: |-
  -----BEGIN CERTIFICATE-----
  ...
  -----END CERTIFICATE-----  

tls.root_cas_file

An optional path of a root certificate authority file to use. This is a file, often with a .pem extension, containing a certificate chain from the parent trusted root certificate, to possible intermediate signing certificates, to the host certificate.

Type: string
Default: ""

# Examples

root_cas_file: ./root_cas.pem

tls.client_certs

A list of client certificates to use. For each certificate either the fields cert and key, or cert_file and key_file should be specified, but not both.

Type: array
Default: []

# Examples

client_certs:
  - cert: foo
    key: bar

client_certs:
  - cert_file: ./example.pem
    key_file: ./example.key

tls.client_certs[].cert

A plain text certificate to use.

Type: string
Default: ""

tls.client_certs[].key

A plain text certificate key to use.

Type: string
Default: ""

tls.client_certs[].cert_file

The path of a certificate to use.

Type: string
Default: ""

tls.client_certs[].key_file

The path of a certificate key to use.

Type: string
Default: ""

tls.client_certs[].password

A plain text password for when the private key is password encrypted in PKCS#1 or PKCS#8 format. The obsolete pbeWithMD5AndDES-CBC algorithm is not supported for the PKCS#8 format. Warning: Since it does not authenticate the ciphertext, it is vulnerable to padding oracle attacks that can let an attacker recover the plaintext.

Type: string
Default: ""

# Example

password: foo

sasl

Specify one or more methods of SASL authentication. SASL is tried in order; if the broker supports the first mechanism, all connections will use that mechanism. If the first mechanism fails, the client will pick the first supported mechanism. If the broker does not support any client mechanisms, connections will fail.

Type: array

# Examples

sasl:
  - mechanism: SCRAM-SHA-512
    password: bar
    username: foo

sasl[].mechanism

The SASL mechanism to use.

Type: string

Option Summary
AWS_MSK_IAM AWS IAM based authentication as specified by the ‘aws-msk-iam-auth’ java library.
OAUTHBEARER OAuth Bearer based authentication.
PLAIN Plain text authentication.
SCRAM-SHA-256 SCRAM based authentication as specified in RFC5802.
SCRAM-SHA-512 SCRAM based authentication as specified in RFC5802.
none Disable sasl authentication

sasl[].username

A username to provide for PLAIN or SCRAM-* authentication.

Type: string
Default: ""

sasl[].password

A password to provide for PLAIN or SCRAM-* authentication.

Type: string
Default: ""

sasl[].token

The token to use for a single session’s OAUTHBEARER authentication.

Type: string
Default: ""

sasl[].extensions

Key/value pairs to add to OAUTHBEARER authentication requests.

Type: object

sasl[].aws

Contains AWS specific fields for when the mechanism is set to AWS_MSK_IAM.

Type: object

sasl[].aws.region

The AWS region to target.

Type: string
Default: ""

sasl[].aws.endpoint

Allows you to specify a custom endpoint for the AWS API.

Type: string
Default: ""

sasl[].aws.credentials

Optional manual configuration of AWS credentials to use.

Type: object

sasl[].aws.credentials.profile

A profile from ~/.aws/credentials to use.

Type: string
Default: ""

sasl[].aws.credentials.id

The ID of credentials to use.

Type: string
Default: ""

sasl[].aws.credentials.secret

The secret for the credentials being used.

Type: string
Default: ""

sasl[].aws.credentials.token`

The token for the credentials being used, required when using short term credentials.

Type: string
Default: ""

sasl[].aws.credentials.from_ec2_role

Use the credentials of a host EC2 machine configured to assume an IAM role associated with the instance.

Type: bool
Default: false
Requires version 4.2.0 or newer

sasl[].aws.credentials.role

A role ARN to assume.

Type: string
Default: ""

sasl[].aws.credentials.role_external_id

An external ID to provide when assuming a role.

Type: string
Default: ""