Docs Connect Components Inputs kafka kafka Type: InputOutput Available in: Cloud, Self-Managed Connects to Kafka brokers and consumes one or more topics. Common Advanced # Common config fields, showing default values input: label: "" kafka: addresses: [] # No default (required) topics: [] # No default (required) target_version: 2.1.0 # No default (optional) consumer_group: "" checkpoint_limit: 1024 auto_replay_nacks: true # All config fields, showing default values input: label: "" kafka: addresses: [] # No default (required) topics: [] # No default (required) target_version: 2.1.0 # No default (optional) 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: "" consumer_group: "" client_id: benthos rack_id: "" start_from_oldest: true checkpoint_limit: 1024 auto_replay_nacks: true commit_period: 1s max_processing_period: 100ms extract_tracing_map: root = @ # No default (optional) group: session_timeout: 10s heartbeat_interval: 3s rebalance_timeout: 60s fetch_buffer_cap: 256 multi_header: false batching: count: 0 byte_size: 0 period: "" check: "" processors: [] # No default (optional) Offsets are managed within Kafka under the specified consumer group, and partitions for each topic are automatically balanced across members of the consumer group. The Kafka input allows parallel processing of messages from different topic partitions, and messages of the same topic partition are processed with a maximum parallelism determined by the field checkpoint_limit. In order to enforce ordered processing of partition messages set the <checkpoint_limit,checkpoint_limit>> to 1 and this will force partitions to be processed in lock-step, where a message will only be processed once the prior message is delivered. Batching messages before processing can be enabled using the batching field, and this batching is performed per-partition such that messages of a batch will always originate from the same partition. This batching mechanism is capable of creating batches of greater size than the checkpoint_limit, in which case the next batch will only be created upon delivery of the current one. Metadata This input adds the following metadata fields to each message: kafka_key kafka_topic kafka_partition kafka_offset kafka_lag kafka_timestamp_unix kafka_tombstone_message All existing message headers (version 0.11+) The field kafka_lag is the calculated difference between the high water mark offset of the partition at the time of ingestion and the current message offset. You can access these metadata fields using function interpolation. Ordering By default messages of a topic partition can be processed in parallel, up to a limit determined by the field checkpoint_limit. However, if strict ordered processing is required then this value must be set to 1 in order to process shard messages in lock-step. When doing so it is recommended that you perform batching at this component for performance as it will not be possible to batch lock-stepped messages at the output level. 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 input. 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. 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 topics A list of topics to consume from. Multiple comma separated topics can be listed in a single element. Partitions are automatically distributed across consumers of a topic. 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. Type: array Requires version 3.33.0 or newer # Examples topics: - foo - bar topics: - foo,bar topics: - foo:0 - bar:1 - bar:3 topics: - foo:0,bar:1,bar:3 topics: - foo:0-5 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 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: "" consumer_group An identifier for the consumer group of the connection. This field can be explicitly made empty in order to disable stored offsets for the consumed topic partitions. Type: string Default: "" client_id An identifier for the client connection. Type: string Default: "benthos" rack_id A rack identifier for this client. Type: string Default: "" 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 checkpoint_limit The maximum number of messages of the same topic and partition that can be processed at a given time. Increasing this limit enables parallel processing and batching at the output level to work on individual partitions. Any given offset will not be committed unless all messages under that offset are delivered in order to preserve at least once delivery guarantees. Type: int Default: 1024 Requires version 3.33.0 or newer 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: "1s" max_processing_period A maximum estimate for the time taken to process a message, this is used for tuning consumer group synchronization. Type: string Default: "100ms" extract_tracing_map EXPERIMENTAL: A Bloblang mapping that attempts to extract an object containing tracing propagation information, which will then be used as the root tracing span for the message. The specification of the extracted fields must match the format used by the service wide tracer. Type: string Requires version 3.45.0 or newer # Examples extract_tracing_map: root = @ extract_tracing_map: root = this.meta.span group Tuning parameters for consumer group synchronization. Type: object group.session_timeout A period after which a consumer of the group is kicked after no heartbeats. Type: string Default: "10s" group.heartbeat_interval A period in which heartbeats should be sent out. Type: string Default: "3s" group.rebalance_timeout A period after which rebalancing is abandoned if unresolved. Type: string Default: "60s" fetch_buffer_cap The maximum number of unprocessed messages to fetch at a given time. Type: int Default: 256 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. 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 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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