Docs Connect Components Outputs kafka kafka Type: OutputInput Available in: Cloud, Self-Managed The kafka output writes a batch of messages to Kafka brokers and waits for acknowledgement before propagating any acknowledgements back to the input. Common Advanced # Common config fields, showing default values output: label: "" kafka: addresses: [] # No default (required) topic: "" # No default (required) target_version: 2.1.0 # No default (optional) key: "" partitioner: fnv1a_hash compression: none static_headers: {} # No default (optional) metadata: exclude_prefixes: [] max_in_flight: 64 batching: count: 0 byte_size: 0 period: "" check: "" # All config fields, showing default values output: label: "" kafka: addresses: [] # No default (required) tls: enabled: false skip_cert_verify: false enable_renegotiation: false root_cas: "" root_cas_file: "" client_certs: [] sasl: mechanism: none user: "" password: "" access_token: "" token_cache: "" token_key: "" topic: "" # No default (required) client_id: benthos target_version: 2.1.0 # No default (optional) rack_id: "" key: "" partitioner: fnv1a_hash partition: "" custom_topic_creation: enabled: false partitions: -1 replication_factor: -1 compression: none static_headers: {} # No default (optional) metadata: exclude_prefixes: [] inject_tracing_map: meta = @.merge(this) # No default (optional) max_in_flight: 64 idempotent_write: false ack_replicas: false max_msg_bytes: 1000000 timeout: 5s retry_as_batch: false batching: count: 0 byte_size: 0 period: "" check: "" processors: [] # No default (optional) max_retries: 0 backoff: initial_interval: 3s max_interval: 10s max_elapsed_time: 30s timestamp_ms: ${! timestamp_unix_milli() } # No default (optional) The configuration field ack_replicas determines whether Redpanda Connect waits for acknowledgement from all replicas or just a single broker. Both the key and topic fields can be dynamically set using function interpolations described in Bloblang queries. Metadata will be added to each message sent as headers (version 0.11+), but can be restricted using the field metadata. Strict ordering and retries When strict ordering is required for messages written to topic partitions it is important to ensure that both the field max_in_flight is set to 1 and that the field retry_as_batch is set to true. You must also ensure that failed batches are never rerouted back to the same output. This can be done by setting the field max_retries to 0 and backoff.max_elapsed_time to empty, which will apply back pressure indefinitely until the batch is sent successfully. However, this also means that manual intervention will eventually be required in cases where the batch cannot be sent due to configuration problems such as an incorrect max_msg_bytes estimate. A less strict but automated alternative would be to route failed batches to a dead letter queue using a fallback broker, but this would allow subsequent batches to be delivered in the meantime whilst those failed batches are dealt with. Troubleshooting If you’re seeing issues writing to or reading from Kafka with this component then it’s worth trying out the newer kafka_franz output. I’m seeing logs that report Failed to connect to kafka: kafka: client has run out of available brokers to talk to (Is your cluster reachable?), but the brokers are definitely reachable. Unfortunately this error message will appear for a wide range of connection problems even when the broker endpoint can be reached. Double check your authentication configuration and also ensure that you have enabled TLS if applicable. Performance This output benefits from sending multiple messages in flight in parallel for improved performance. You can tune the max number of in flight messages (or message batches) with the field max_in_flight. This output benefits from sending messages as a batch for improved performance. Batches can be formed at both the input and output level. You can find out more in this doc. Fields addresses A list of broker addresses to connect to. If an item of the list contains commas it will be expanded into multiple addresses. Type: array # Examples addresses: - localhost:9092 addresses: - localhost:9041,localhost:9042 addresses: - localhost:9041 - localhost:9042 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 Requires version 3.45.0 or newer 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. This field contains sensitive information that usually shouldn’t be added to a configuration directly. For more information, see Secrets. 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. This field contains sensitive information that usually shouldn’t be added to a configuration directly. For more information, see Secrets. 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. Because the obsolete pbeWithMD5AndDES-CBC algorithm does not authenticate the ciphertext, it is vulnerable to padding oracle attacks that can let an attacker recover the plaintext. This field contains sensitive information that usually shouldn’t be added to a configuration directly. For more information, see Secrets. Type: string Default: "" # Examples password: foo password: ${KEY_PASSWORD} sasl Enables SASL authentication. Type: object sasl.mechanism The SASL authentication mechanism, if left empty SASL authentication is not used. Type: string Default: "none" Option Summary OAUTHBEARER OAuth Bearer based authentication. PLAIN Plain text authentication. NOTE: When using plain text auth it is extremely likely that you’ll also need to enable TLS. SCRAM-SHA-256 Authentication using the SCRAM-SHA-256 mechanism. SCRAM-SHA-512 Authentication using the SCRAM-SHA-512 mechanism. none Default, no SASL authentication. sasl.user A PLAIN username. It is recommended that you use environment variables to populate this field. Type: string Default: "" # Examples user: ${USER} sasl.password A PLAIN password. It is recommended that you use environment variables to populate this field. This field contains sensitive information that usually shouldn’t be added to a configuration directly. For more information, see Secrets. Type: string Default: "" # Examples password: ${PASSWORD} sasl.access_token A static OAUTHBEARER access token Type: string Default: "" sasl.token_cache Instead of using a static access_token allows you to query a cache resource to fetch OAUTHBEARER tokens from Type: string Default: "" sasl.token_key Required when using a token_cache, the key to query the cache with for tokens. Type: string Default: "" topic The topic to publish messages to. This field supports interpolation functions. Type: string client_id An identifier for the client connection. Type: string Default: "benthos" target_version The version of the Kafka protocol to use. This limits the capabilities used by the client and should ideally match the version of your brokers. Defaults to the oldest supported stable version. Type: string # Examples target_version: 2.1.0 target_version: 3.1.0 rack_id A rack identifier for this client. Type: string Default: "" key The key to publish messages with. This field supports interpolation functions. Type: string Default: "" partitioner The partitioning algorithm to use. Type: string Default: "fnv1a_hash" Options: fnv1a_hash , murmur2_hash , random , round_robin , manual . partition The manually-specified partition to publish messages to, relevant only when the field partitioner is set to manual. Must be able to parse as a 32-bit integer. This field supports interpolation functions. Type: string Default: "" custom_topic_creation If enabled, topics will be created with the specified number of partitions and replication factor if they do not already exist. Type: object custom_topic_creation.enabled Whether to enable custom topic creation. Type: bool Default: false custom_topic_creation.partitions The number of partitions to create for new topics. Leave at -1 to use the broker configured default. Must be >= 1. Type: int Default: -1 custom_topic_creation.replication_factor The replication factor to use for new topics. Leave at -1 to use the broker configured default. Must be an odd number, and less then or equal to the number of brokers. Type: int Default: -1 compression The compression algorithm to use. Type: string Default: "none" Options: none , snappy , lz4 , gzip , zstd . static_headers An optional map of static headers that should be added to messages in addition to metadata. Type: object # Examples static_headers: first-static-header: value-1 second-static-header: value-2 metadata Specify criteria for which metadata values are sent with messages as headers. Type: object metadata.exclude_prefixes Provide a list of explicit metadata key prefixes to be excluded when adding metadata to sent messages. Type: array Default: [] inject_tracing_map EXPERIMENTAL: A Bloblang mapping used to inject an object containing tracing propagation information into outbound messages. The specification of the injected fields will match the format used by the service wide tracer. Type: string Requires version 3.45.0 or newer # Examples inject_tracing_map: meta = @.merge(this) inject_tracing_map: root.meta.span = this max_in_flight The maximum number of messages to have in flight at a given time. Increase this to improve throughput. Type: int Default: 64 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: false ack_replicas Ensure that messages have been copied across all replicas before acknowledging receipt. Type: bool Default: false max_msg_bytes The maximum size in bytes of messages sent to the target topic. Type: int Default: 1000000 timeout The maximum period of time to wait for message sends before abandoning the request and retrying. Type: string Default: "5s" retry_as_batch When enabled forces an entire batch of messages to be retried if any individual message fails on a send, otherwise only the individual messages that failed are retried. Disabling this helps to reduce message duplicates during intermittent errors, but also makes it impossible to guarantee strict ordering of messages. Type: bool Default: false 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_retries The maximum number of retries before giving up on the request. If set to zero there is no discrete limit. Type: int Default: 0 backoff Control time intervals between retry attempts. Type: object backoff.initial_interval The initial period to wait between retry attempts. The retry interval increases for each failed attempt, up to the backoff.max_interval value. Type: string Default: "3s" # Examples initial_interval: 50ms initial_interval: 1s backoff.max_interval The maximum period to wait between retry attempts Type: string Default: "10s" # Examples max_interval: 5s max_interval: 1m backoff.max_elapsed_time The maximum overall period of time to spend on retry attempts before the request is aborted. Setting this value to a zeroed duration (such as 0s) will result in unbounded retries. Type: string Default: "30s" # Examples max_elapsed_time: 1m max_elapsed_time: 1h timestamp_ms Set a timestamp (in milliseconds) for each message (optional). 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") } Back to top × Simple online edits For simple changes, such as fixing a typo, you can edit the content directly on GitHub. 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