load_kafka

Loads a byte stream from an Apache Kafka topic.

load_kafka topic:string, [count=int, exit=bool, offset=int|string, options=record,
           aws_iam=record, commit_batch_size=int, commit_timeout=duration]

Description

The load_kafka operator reads bytes from a Kafka topic.

The implementation uses the official librdkafka from Confluent and supports all configuration options. You can specify them via options parameter as {key: value, ...}.

The operator injects the following default librdkafka configuration values in case no configuration file is present, or when the configuration does not include them:

• bootstrap.servers: localhost
• client.id: tenzir
• group.id: tenzir
• enable.auto.commit: false (This option cannot be changed)

topic: string

The Kafka topic to use.

count = int (optional)

Exit successfully after having consumed count messages.

exit = bool (optional)

Exit successfully after having received the last message.

Without this option, the operator waits for new messages after consuming the last one.

offset = int|string (optional)

The offset to start consuming from. Possible values are:

• "beginning": first offset
• "end": last offset
• "stored": stored offset
• <value>: absolute offset
• -<value>: relative offset from end

The default is "stored".

options = record (optional)

A record of key-value configuration options for librdkafka, e.g., {"auto.offset.reset" : "earliest", "enable.partition.eof": true}.

The load_kafka operator passes the key-value pairs directly to librdkafka. Consult the list of available configuration options to configure Kafka according to your needs.

We recommend factoring these options into the plugin-specific kafka.yaml so that they are independent of the load_kafka arguments.

commit_batch_size = int (optional)

The operator commits offsets after receiving commit_batch_size messages to improve throughput. If you need to ensure exactly-once semantics for your pipeline, set this option to 1 to commit every message individually.

Defaults to 1000.

commit_timeout = duration (optional)

A timeout after which the operator commits messages, even if it accepted fewer than commit_batch_size. This helps with long-running, low-volume pipelines.

Defaults to 10s.

aws_iam = record (optional)

If specified, enables using AWS IAM Authentication for MSK. The keys must be non-empty when specified.

Available keys:

• region: Region of the MSK Clusters. Must be specified when using IAM.
• assume_role: Optional role ARN to assume.
• session_name: Optional session name to use when assuming a role.
• external_id: Optional external id to use when assuming a role.

The operator tries to get credentials in the following order:

1. Checks your environment variables for AWS Credentials.
2. Checks your $HOME/.aws/credentials file for a profile and credentials
3. Contacts and logs in to a trusted identity provider. The login information to these providers can either be on the environment variables: AWS_ROLE_ARN, AWS_WEB_IDENTITY_TOKEN_FILE, AWS_ROLE_SESSION_NAME or on a profile in your $HOME/.aws/credentials.
4. Checks for an external method set as part of a profile on $HOME/.aws/config to generate or look up credentials that isn’t directly supported by AWS.
5. Contacts the ECS Task Role to request credentials if Environment variable AWS_CONTAINER_CREDENTIALS_RELATIVE_URI has been set.
6. Contacts the EC2 Instance Metadata service to request credentials if AWS_EC2_METADATA_DISABLED is NOT set to ON.

Examples

Read 100 JSON messages from the topic tenzir

load_kafka "tenzir", count=100
read_json

Read Zeek Streaming JSON logs starting at the beginning

load_kafka "zeek", offset="beginning"
read_zeek_json

See Also

save_kafka