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kafka_franz

A Kafka input using the Franz Kafka client library.

# Common config fields, showing default values
input:
  label: ""
  kafka_franz:
    seed_brokers: [] # No default (required)
    topics: [] # No default (required)
    regexp_topics: false
    regexp_topics_include: []
    regexp_topics_exclude: []
    transaction_isolation_level: read_uncommitted
    consumer_group: "" # No default (optional)
    auto_replay_nacks: true

When a consumer group is specified this input consumes one or more topics where partitions will automatically balance across any other connected clients with the same consumer group. When a consumer group is not specified topics can either be consumed in their entirety or with explicit partitions.

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

Metadata​

This input adds the following metadata fields to each message:

- kafka_key
- kafka_topic
- kafka_partition
- kafka_offset
- kafka_timestamp_unix
- kafka_tombstone_message
- All record headers

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

topics​

A list of topics to consume from. Multiple comma separated topics can be listed in a single element. When a consumer_group is specified partitions are automatically distributed across consumers of a topic, otherwise all partitions are consumed.

Alternatively, it's possible to specify explicit partitions to consume from with a colon after the topic name, e.g. foo:0 would consume the partition 0 of the topic foo. This syntax supports ranges, e.g. foo:0-10 would consume partitions 0 through to 10 inclusive.

Finally, it's also possible to specify an explicit offset to consume from by adding another colon after the partition, e.g. foo:0:10 would consume the partition 0 of the topic foo starting from the offset 10. If the offset is not present (or remains unspecified) then the field start_from_oldest determines which offset to start from.

Type: array

# Examples

topics:
  - foo
  - bar

topics:
  - things.*

topics:
  - foo,bar

topics:
  - foo:0
  - bar:1
  - bar:3

topics:
  - foo:0,bar:1,bar:3

topics:
  - foo:0-5

regexp_topics​

Whether listed topics should be interpreted as regular expression patterns for matching multiple topics. When topics are specified with explicit partitions this field must remain set to false.

Type: bool
Default: false

regexp_topics_include​

A list of regular expression patterns for matching topics to consume from. Topics that match any of these patterns are included.

Type: array
Default: []

regexp_topics_exclude​

A list of regular expression patterns for excluding topics from consumption. Topics that match any of these patterns are excluded.

Type: array
Default: []

transaction_isolation_level​

The transaction isolation level

Type: string
Default: "read_uncommitted"

OptionSummary
read_committedIf set, only committed transactional records are processed.
read_uncommittedIf set, then uncommitted records are processed.

consumer_group​

An optional consumer group to consume as. When specified the partitions of specified topics are automatically distributed across consumers sharing a consumer group, and partition offsets are automatically committed and resumed under this name. Consumer groups are not supported when specifying explicit partitions to consume from in the topics field.

Type: string

client_id​

An identifier for the client connection.

Type: string
Default: "expanso_edge"

rack_id​

A rack identifier for this client.

Type: string
Default: ""

instance_id​

When using a consumer group, an instance ID specifies the groups static membership, which can prevent rebalances during reconnects. When using a instance ID the client does NOT leave the group when closing. To actually leave the group one must use an external admin command to leave the group on behalf of this instance ID. This ID must be unique per consumer within the group.

Type: string
Default: ""

rebalance_timeout​

When using a consumer group, rebalance_timeout sets how long group members are allowed to take when a rebalance has begun. This timeout is how long all members are allowed to complete work and commit offsets, minus the time it took to detect the rebalance (from a heartbeat).

Type: string
Default: "45s"

session_timeout​

When using a consumer group, session_timeout sets how long a member in the group can go between heartbeats. If a member does not heartbeat in this timeout, the broker will remove the member from the group and initiate a rebalance.

Type: string
Default: "1m"

heartbeat_interval​

When using a consumer group, heartbeat_interval sets how long a group member goes between heartbeats to Kafka. Kafka uses heartbeats to ensure that a group member's session stays active. This value should be no higher than 1/3rd of the session_timeout. This is equivalent to the Java heartbeat.interval.ms setting.

Type: string
Default: "3s"

checkpoint_limit​

caution

Setting this checkpoint_limit: 1will not enforce 'strict ordered' processing of records. Use the kafka input processor for 'strict ordered' processing.

Determines how many messages of the same partition can be processed in parallel before applying back pressure. When a message of a given offset is delivered to the output the offset is only allowed to be committed when all messages of prior offsets have also been delivered, this ensures at-least-once delivery guarantees. However, this mechanism also increases the likelihood of duplicates in the event of crashes or server faults, reducing the checkpoint limit will mitigate this.

Type: int
Default: 1024

auto_replay_nacks​

Whether messages that are rejected (nacked) at the output level should be automatically replayed indefinitely, eventually resulting in back pressure if the cause of the rejections is persistent. If set to false these messages will instead be deleted. Disabling auto replays can greatly improve memory efficiency of high throughput streams as the original shape of the data can be discarded immediately upon consumption and mutation.

Type: bool
Default: true

commit_period​

The period of time between each commit of the current partition offsets. Offsets are always committed during shutdown.

Type: string
Default: "5s"

start_from_oldest​

Determines whether to consume from the oldest available offset, otherwise messages are consumed from the latest offset. The setting is applied when creating a new consumer group or the saved offset no longer exists.

Type: bool
Default: true

start_offset​

Sets the offset to start consuming from, or if OffsetOutOfRange is seen while fetching, to restart consuming from.

Type: string
Default: "earliest"

OptionSummary
committedPrevents consuming a partition in a group if the partition has no prior commits. Corresponds to Kafka's auto.offset.reset=none option
earliestStart from the earliest offset. Corresponds to Kafka's auto.offset.reset=earliest option.
latestStart from the latest offset. Corresponds to Kafka's auto.offset.reset=latest option.

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"

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"

fetch_max_bytes​

This sets the maximum amount of bytes a broker will try to send during a fetch. Note that brokers may not obey this limit if it has records larger than this limit. Also note that this client sends a fetch to each broker concurrently, meaning the client will buffer up to <brokers * max bytes> worth of memory. Equivalent to Kafka's fetch.max.bytes option.

Type: string
Default: "50MiB"

fetch_max_partition_bytes​

Sets the maximum amount of bytes that will be consumed for a single partition in a fetch request. Note that if a single batch is larger than this number, that batch will still be returned so the client can make progress. Equivalent to Kafka's max.partition.fetch.bytes option.

Type: string
Default: "1MiB"

fetch_max_wait​

This sets the maximum amount of time a broker will wait for a fetch response to hit the minimum number of required bytes before returning, overriding the default 5s.

Type: string
Default: "5s"

fetch_min_bytes​

Sets the minimum amount of bytes a broker will try to send during a fetch. This is the equivalent to the Java fetch.min.bytes setting.

Type: string
Default: "1B"

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}

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"

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: ""

multi_header​

Decode headers into lists to allow handling of multiple values with the same key

Type: bool
Default: false

batching​

Allows you to configure a batching policy that applies to individual topic partitions in order to batch messages together before flushing them for processing. Batching can be beneficial for performance as well as useful for windowed processing, and doing so this way preserves the ordering of topic partitions.

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

topic_lag_refresh_period​

The period of time between each topic lag refresh cycle.

Type: string
Default: "5s"

timely_nacks_maximum_wait​

EXPERIMENTAL: Specify a maximum period of time in which each message can be consumed and awaiting either acknowledgement or rejection before rejection is instead forced. This can be useful for avoiding situations where certain downstream components can result in blocked confirmation of delivery that exceeds SLAs.

Type: string