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kafka_franz

A Kafka output using the Franz Kafka client library.

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

Writes a batch of messages to Kafka brokers and waits for acknowledgement 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

OptionSummary
least_backupChooses the least backed up partition (the partition with the fewest amount of buffered records). Partitions are selected per batch.
manualManually select a partition for each message, requires the field partition to be specified.
murmur2_hashKafka's default hash algorithm that uses a 32-bit murmur2 hash of the key to compute which partition the record will be on.
round_robinRound-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.
uniform_bytesPartitions based on byte size.

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: ${! metadata("partition") }

client_id​

An identifier for the client connection.

Type: string
Default: "expanso_edge"

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

acks​

The number of acknowledgements the leader broker must receive from ISR brokers before responding to the produce request. When idempotent_write is enabled this must be set to all.

Type: string
Default: "all"

OptionSummary
allWait for all in-sync replicas to acknowledge (acks=-1). Required when idempotent_write is enabled.
leaderWait for the leader broker to acknowledge (acks=1). Messages are lost if the leader fails before replication.
noneDo not wait for any acknowledgement (acks=0). Highest throughput but messages may be lost.

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$

timestamp_ms​

An optional timestamp to set for each message expressed in milliseconds. When left empty, the current timestamp is used. This field supports interpolation functions.

Type: string

# Examples

timestamp_ms: ${! timestamp_unix_milli() }

timestamp_ms: ${! metadata("kafka_timestamp_ms") }

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"

request_timeout_overhead​

The request time overhead. Uses the given time as overhead while deadlining requests. Roughly equivalent to request.timeout.ms, but grants additional time to requests that have timeout fields.

Type: string
Default: "10s"

conn_idle_timeout​

The rough amount of time to allow connections to idle before they are closed.

Type: string
Default: "20s"

tcp​

TCP socket configuration.

Type: object

tcp.connect_timeout​

Maximum amount of time a dial will wait for a connect to complete. Zero disables.

Type: string
Default: "0s"

tcp.keep_alive​

TCP keep-alive probe configuration.

Type: object

tcp.keep_alive.idle​

Duration the connection must be idle before sending the first keep-alive probe. Zero defaults to 15s. Negative values disable keep-alive probes.

Type: string
Default: "15s"

tcp.keep_alive.interval​

Duration between keep-alive probes. Zero defaults to 15s.

Type: string
Default: "15s"

tcp.keep_alive.count​

Maximum unanswered keep-alive probes before dropping the connection. Zero defaults to 9.

Type: int
Default: 9

tcp.tcp_user_timeout​

Maximum time to wait for acknowledgment of transmitted data before killing the connection. Linux-only (kernel 2.6.37+), ignored on other platforms. When enabled, keep_alive.idle must be greater than this value per RFC 5482. Zero disables.

Type: string
Default: "0s"

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: 10
  jitter: 0.1
  period: 10s

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.jitter​

A non-negative factor that adds random delay to batch flush intervals, where delay is determined uniformly at random between 0 and jitter * period. For example, with period: 100ms and jitter: 0.1, each flush will be delayed by a random duration between 0-10ms.

Type: float
Default: 0

# Examples

jitter: 0.01

jitter: 0.1

jitter: 1

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

broker_write_max_bytes​

The upper bound for the number of bytes written to a broker connection in a single write. This field corresponds to Kafka's socket.request.max.bytes.

Type: string
Default: "100MiB"

# Examples

broker_write_max_bytes: 128MB

broker_write_max_bytes: 50mib

max_buffered_records​

Sets the max amount of records the client will buffer, blocking produces until records are finished if this limit is reached. This overrides the franz-kafka default of 10,000.

Type: int
Default: 10000

max_buffered_bytes​

The maximum number of bytes the client will buffer in memory before blocking. When this limit is reached, Produce() calls will block until buffered records are delivered. Set to 0 to disable the byte-level limit (only max_buffered_records applies). This limit is checked after max_buffered_records.

Type: string
Default: "0"

# Examples

max_buffered_bytes: 256MB

max_buffered_bytes: 50mib

max_in_flight_requests​

The maximum number of produce requests in flight per broker connection. When idempotent_write is enabled, this is capped at 5 by the Kafka protocol (and at 1 for Kafka < v1.0.0). When idempotent_write is disabled, higher values improve throughput by pipelining requests but may cause out-of-order delivery.

Type: int
Default: 1

record_retries​

The maximum number of times a record produce is retried on failure before the record is failed. When a record fails, all records buffered in the same partition are also failed to preserve gapless ordering. Set to 0 for unlimited retries (the default). With idempotent_write enabled, retries are only enforced when safe to do so without creating invalid sequence numbers.

Type: int
Default: 0

record_delivery_timeout​

The maximum time a record can sit in the producer buffer before it is failed, roughly equivalent to Kafka's delivery.timeout.ms. This is evaluated before writing a request or after a produce response. When a record times out, all records in the same partition are also failed. Set to 0s for no timeout (the default). With idempotent_write enabled, timeouts are only enforced when safe to do so without creating invalid sequence numbers.

Type: string
Default: "0s"

metadata_max_age​

This sets the maximum age for the client's cached metadata, to allow detection of new topics, partitions, etc.

Type: string
Default: "5m"

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.

allow_auto_topic_creation​

Enables topics to be auto created if they do not exist when fetching their metadata.

Type: bool
Default: true

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. :::warning Secret This field contains sensitive information that usually shouldn't be added to a config directly, read our secrets page for more info. :::

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. :::warning Secret This field contains sensitive information that usually shouldn't be added to a config directly, read our secrets page for more info. :::

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. :::warning Secret This field contains sensitive information that usually shouldn't be added to a config directly, read our secrets page for more info. :::

Type: string
Default: ""

# Examples

password: foo

password: ${KEY_PASSWORD}

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

OptionSummary
AWS_MSK_IAMAWS IAM based authentication as specified by the 'aws-msk-iam-auth' java library.
OAUTHBEAREROAuth Bearer based authentication.
PLAINPlain text authentication.
SCRAM-SHA-256SCRAM based authentication as specified in RFC5802.
SCRAM-SHA-512SCRAM based authentication as specified in RFC5802.
noneDisable 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. :::warning Secret This field contains sensitive information that usually shouldn't be added to a config directly, read our secrets page for more info. :::

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. More information can be found in this document.

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. :::warning Secret This field contains sensitive information that usually shouldn't be added to a config directly, read our secrets page for more info. :::

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

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: ""