redpanda

Type:

Available in: Cloud, Self-Managed

Consumes topic data from one or more Kafka brokers.

# Common configuration fields, showing default values
input:
  label: ""
  redpanda:
    seed_brokers: [] # No default (required)
    topics: [] # No default (required)
    regexp_topics: false
    consumer_group: "" # No default (optional)
    auto_replay_nacks: true
yml

Consumer groups

When you specify a consumer group in your configuration, this input consumes one or more topics and automatically balances the topic partitions across any other connected clients with the same consumer group. Otherwise, topics are consumed in their entirety or with explicit partitions.

Delivery guarantees

If you choose to use consumer groups, the offsets of records received by Redpanda Connect are committed automatically. In the event of restarts, this input uses the committed offsets to resume data consumption where it left off.

Redpanda Connect guarantees at-least-once delivery. Records are only confirmed as delivered when all downstream outputs that a record is routed to have also confirmed delivery.

Ordering

To preserve the order of topic partitions:

  • Records consumed from each partition are processed and delivered in the order that they are received

  • Only one batch of records of a given partition is processed at a time

This approach means that although records from different partitions may be processed in parallel, records from the same partition are processed in sequential order.

Delivery errors

The order in which records are delivered may be disrupted by delivery errors and any error-handling mechanisms that start up. Redpanda Connect leans towards at-least-once delivery unless instructed otherwise, and this includes reattempting delivery of data when the ordering of that data is no longer guaranteed.

For example, a batch of records is sent to an output broker and only a subset of records are delivered. In this scenario, Redpanda Connect (by default) attempts to deliver the records that failed, even though these delivery failures may have been sent before records that were delivered successfully.

Use a fallback output

To prevent delivery errors from disrupting the order of records, you must specify a fallback output in your pipeline configuration. When adding a fallback output, it is good practice to set the auto_retry_nacks field to false. This also improves the throughput of your pipeline.

For example, the following configuration includes a fallback output. If Redpanda Connect fails to write delivery errors to the foo topic, it then attempts to write them into a dead letter queue topic (foo_dlq), which is retried indefinitely as a way to apply back pressure.

output:
  fallback:
    - redpanda_common:
        topic: foo
    - retry:
        output:
          redpanda_common:
            topic: foo_dlq
yaml

Batching

Records are processed and delivered from each partition in the same batches as they are received from brokers. Batch sizes are dynamically sized in order to optimize throughput, but you can tune them further using the following configuration fields:

  • fetch_max_partition_bytes

  • fetch_max_bytes

You can break batches down further using the split processor.

Metrics

This input emits a redpanda_lag metric with topic and partition labels for each consumed topic. The metric records the number of produced messages that remain to be read from each topic/partition pair by the specified consumer group.

Metadata

This input adds the following metadata fields to each message:

  • kafka_key

  • kafka_topic

  • kafka_partition

  • kafka_offset

  • kafka_lag

  • kafka_timestamp_ms

  • kafka_timestamp_unix

  • kafka_tombstone_message

  • All record headers

Fields

seed_brokers

A list of broker addresses to connect to in order. Use commas to separate multiple addresses in a single list item.

Type: array

# Examples

seed_brokers:
  - localhost:9092

seed_brokers:
  - foo:9092
  - bar:9092

seed_brokers:
  - foo:9092,bar:9092
yml

client_id

An identifier for the client connection.

Type: string

Default: benthos

tls

Override system defaults with custom TLS settings.

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 request renegotiation. Enable this option if you’re seeing the error message local error: tls: no renegotiation.

Type: bool

Default: false

tls.root_cas

Specify a certificate authority to use (optional). This is a string that represents a certificate chain from the parent trusted root certificate, through possible intermediate signing certificates, to the host certificate.

This field contains sensitive information that usually shouldn’t be added to a configuration directly. For more information, see Manage Secrets before adding it to your configuration.

Type: string

Default: ""

# Examples

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

tls.root_cas_file

Specify the path to a root certificate authority file (optional). This is a file, often with a .pem extension, which contains a certificate chain from the parent trusted root certificate, through possible intermediate signing certificates, to the host certificate.

Type: string

Default: ""

# Examples

root_cas_file: ./root_cas.pem
yml

tls.client_certs

A list of client certificates to use. For each certificate specify values for either the cert and key fields, or cert_file and key_file fields.

Type: array

Default: []

# Examples

client_certs:
  - cert: foo
    key: bar

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

tls.client_certs[].cert

The plain text certificate to use.

Type: string

Default: ""

tls.client_certs[].key

The plain text certificate key to use.

This field contains sensitive information that usually shouldn’t be added to a configuration directly. For more information, see Manage Secrets before adding it to your configuration.

Type: string

Default: ""

tls.client_certs[].cert_file

The path to the 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

The 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.

The pbeWithMD5AndDES-CBC algorithm does not authenticate ciphertext, and is vulnerable to padding oracle attacks which may allow an attacker to recover the plain text password.

This field contains sensitive information that usually shouldn’t be added to a configuration directly. For more information, see Manage Secrets before adding it to your configuration.

Type: string

Default: ""

# Examples

password: foo

password: ${KEY_PASSWORD}
yml

sasl

Specify one or more methods or mechanisms of SASL authentication. They are tried in order. If the broker supports the first SASL mechanism, all connections use it. If the first mechanism fails, the client picks the first supported mechanism. If the broker does not support any client mechanisms, all connections fail.

Type: array

# Examples

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

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 RFC 5802

SCRAM-SHA-512

SCRAM-based authentication as specified in RFC 5802

none

Disable SASL authentication

sasl[].username

A username for PLAIN or SCRAM-* authentication.

Type: string

Default: ""

sasl[].password

A password for PLAIN or SCRAM-* authentication.

This field contains sensitive information that usually shouldn’t be added to a configuration directly. For more information, see Manage Secrets before adding it to your configuration.

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

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

Specify a custom endpoint for the AWS API.

Type: string

Default: ""

sasl[].aws.credentials

Manually configure the AWS credentials to use (optional). For more information, see the Amazon Web Services guide.

Type: object

sasl[].aws.credentials.profile

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

Type: string

Default: ""

sasl[].aws.credentials.id

The ID of the AWS credentials to use.

Type: string

Default: ""

sasl[].aws.credentials.secret

The secret for the AWS credentials in use.

This field contains sensitive information that usually shouldn’t be added to a configuration directly. For more information, see Manage Secrets before adding it to your configuration.

Type: string

Default: ""

sasl[].aws.credentials.token

The token for the AWS credentials in use. This is a required value for 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

The role ARN to assume.

Type: string

Default: ""

sasl[].aws.credentials.role_external_id

An external ID to use when assuming a role.

Type: string

Default: ""

metadata_max_age

The maximum period of time after which metadata is refreshed.

Type: string

Default: 5m

topics

A list of topics to consume from. Use commas to separate multiple topics 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, you can specify explicit partitions to consume by using a colon after the topic name. For example, foo:0 would consume the partition 0 of the topic foo. This syntax supports ranges. For example, foo:0-10 would consume partitions 0 through to 10 inclusive.

It is also possible to specify an explicit offset to consume from by adding another colon after the partition. For example, 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
yml

regexp_topics

Whether listed topics are 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

rack_id

A rack specifies where the client is physically located, and changes fetch requests to consume from the closest replica as opposed to the leader replica.

Type: string

Default ""

instance_id

When you specify a consumer_group, assign a unique value to instance_id to define the group’s static membership, which can prevent unnecessary rebalances during reconnections.

When you assign an instance ID, the client does not automatically leave the consumer group when it disconnects. To remove the client, you must use an external admin command on behalf of the instance ID.

Type: string

Default ""

# Examples

instance_id: redpanda_input_5

instance_id: redpanda_input_6
yml

rebalance_timeout

When you specify a consumer_group, rebalance_timeout sets a time limit for all consumer group members to complete their work and commit offsets after a rebalance has begun. The timeout excludes the time taken to detect a failed or late heartbeat, which indicates a rebalance is required.

Type: string

Default: 45s

session_timeout

When you specify a consumer_group, session_timeout sets the maximum interval between heartbeats sent by a consumer group member to the broker. If a broker doesn’t receive a heartbeat from a group member before the timeout expires, it removes the member from the consumer group and initiates a rebalance.

broker

Type: string

Default: 1m

heartbeat_interval

When you specify a consumer_group, heartbeat_interval sets how frequently a consumer group member should send heartbeats to Apache Kafka. Apache Kafka uses heartbeats to make sure that a group member’s session is active.

You must set heartbeat_interval to less than one-third of session_timeout.

This field is equivalent to the Java heartbeat.interval.ms setting.

client

Type: string

Default: 3s

start_from_oldest

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

Type: bool

Default: true

fetch_max_bytes

The maximum number of bytes that a broker tries to send during a fetch.

If individual records are larger than the fetch_max_bytes value, brokers will still send them.

Type: string

Default: 50MiB

fetch_max_wait

The maximum period of time a broker can wait for a fetch response to reach the required minimum number of bytes (fetch_min_bytes).

Type: string

Default: 5s

fetch_min_bytes

The minimum number of bytes that a broker tries to send during a fetch. This field is equivalent to the Java setting fetch.min.bytes.

Type: string

Default: 1B

fetch_max_partition_bytes

The maximum number of bytes that are consumed from a single partition in a fetch request. This field is equivalent to the Java setting fetch.max.partition.bytes.

If a single batch is larger than the fetch_max_partition_bytes value, the batch is still sent so that the client can make progress.

Type: string

Default: 1MiB

consumer_group

An optional consumer group. When this value is specified:

  • The partitions of any topics, specified in the topics field, are automatically distributed across consumers sharing a consumer group

  • Partition offsets are automatically committed and resumed under this name

Consumer groups are not supported when you specify explicit partitions to consume from in the topics field.

Type: string

commit_period

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

Type: string

Default: 5s

partition_buffer_bytes

A buffer size (in bytes) for each consumed partition, which allows the internal queuing of records before they are flushed. Increasing this value may improve throughput but results in higher memory utilization.

Each buffer can grow slightly beyond this value.

Type: string

Default: 1MB

topic_lag_refresh_period

The interval between refresh cycles. During each cycle, this input queries the Repanda Connect server to calculate the topic lag - the number of produced messages that remain to be read from each topic/partition pair by the specified consumer group.

Type: string

Default: 5s

auto_replay_nacks

Whether to automatically replay messages that are rejected (nacked) at the output level. If the cause of rejections is persistent, leaving this option enabled can result in back pressure.

Set auto_replay_nacks to false to delete rejected messages. Disabling auto replays can greatly improve memory efficiency of high throughput streams, as the original shape of the data is discarded immediately upon consumption and mutation.

Type: bool

Default: true