Lake Loader configuration reference

The configuration reference in this page is written for Lake Loader 0.5.0

Table configuration

Delta Lake

Parameter	Description
output.good.location	Required, e.g. gs://mybucket/events. URI of the bucket location to which to write Snowplow enriched events in Delta format. The URI should start with the following prefix: s3a:// on AWS gs:// on GCP abfs:// on Azure
output.good.deltaTableProperties.*	Optional. A map of key/value strings corresponding to Delta's table properties. These can be anything from the Delta table properties documentation. The default properties include configuring Delta's data skipping feature for the important Snowplow timestamp columns: load_tstamp, collector_tstamp, derived_tstamp, dvce_created_tstamp.

Iceberg / Glue

Parameter	Description
output.good.type	Required, set this to Iceberg
output.good.catalog.type	Required, set this to Glue
output.good.location	Required, e.g. s3a://mybucket/events. URI of the bucket location to which to write Snowplow enriched events in Iceberg format. The URI should start with s3a://
output.good.database	Required. Name of the database in the Glue catalog
output.good.table	Required. The name of the table in the Glue database
output.good.icebergTableProperties.*	Optional. A map of key/value strings corresponding to Iceberg's table properties. These can be anything from the Iceberg table properties documentation. The default properties include configuring Iceberg's column-level statistics for the important Snowplow timestamp columns: load_tstamp, collector_tstamp, derived_tstamp, dvce_created_tstamp.
output.good.catalog.options.*	Optional. A map of key/value strings which are passed to the catalog configuration. These can be anything from the Iceberg catalog documentation e.g. "glue.id": "1234567"

Hudi

Alternative Docker image

To use the Lake Loader with Hudi support, pull the appropriate alternative image from Docker Hub, e.g. snowplow/lake-loader-aws:0.5.0-hudi.

Parameter	Description
output.good.location	Required, e.g. gs://mybucket/events. URI of the bucket location to which to write Snowplow enriched events in Hudi format. The URI should start with the following prefix: s3a:// on AWS gs:// on GCP abfs:// on Azure
output.good.hudiWriteOptions.*	Optional. A map of key/value strings corresponding to Hudi's configuration options for writing into a table. The default options configure load_tstamp as the table's partition field.
output.good.hudiTableProperties.*	Optional. A map of key/value strings corresponding to Hudi's configuration options for creating a table. The default options configure load_tstamp as the table's partition field.

Streams configuration

AWS

Parameter	Description
input.streamName	Required. Name of the Kinesis stream with the enriched events
input.appName	Optional, default snowplow-lake-loader. Name to use for the dynamodb table, used by the underlying Kinesis Consumer Library for managing leases.
input.initialPosition	Optional, default LATEST. Allowed values are LATEST, TRIM_HORIZON, AT_TIMESTAMP. When the loader is deployed for the first time, this controls from where in the kinesis stream it should start consuming events. On all subsequent deployments of the loader, the loader will resume from the offsets stored in the DynamoDB table.
input.initialPosition.timestamp	Required if input.initialPosition is AT_TIMESTAMP. A timestamp in ISO8601 format from where the loader should start consuming events.
input.retrievalMode	Optional, default Polling. Change to FanOut to enable the enhance fan-out feature of Kinesis.
input.retrievalMode.maxRecords	Optional. Default value 1000. How many events the Kinesis client may fetch in a single poll. Only used when `input.retrievalMode` is Polling.
input.workerIdentifier	Optional. Defaults to the HOSTNAME environment variable. The name of this KCL worker used in the dynamodb lease table.
input.leaseDuration	Optional. Default value 10 seconds. The duration of shard leases. KCL workers must periodically refresh leases in the dynamodb table before this duration expires.
output.bad.streamName	Required. Name of the Kinesis stream that will receive failed events.
output.bad.throttledBackoffPolicy.minBackoff	Optional. Default value 100 milliseconds. Initial backoff used to retry sending failed events if we exceed the Kinesis write throughput limits.
output.bad.throttledBackoffPolicy.maxBackoff	Optional. Default value 1 second. Maximum backoff used to retry sending failed events if we exceed the Kinesis write throughput limits.
output.bad.recordLimit	Optional. Default value 500. The maximum number of records we are allowed to send to Kinesis in 1 PutRecords request.
output.bad.byteLimit	Optional. Default value 5242880. The maximum number of bytes we are allowed to send to Kinesis in 1 PutRecords request.

GCP

Parameter	Description
input.subscription	Required, e.g. projects/myproject/subscriptions/snowplow-enriched. Name of the Pub/Sub subscription with the enriched events
input.parallelPullCount	Optional. Default value 3. Number of threads used internally by the pubsub client library for fetching events
input.bufferMaxBytes	Optional. Default value 1000000. How many bytes can be buffered by the loader app before blocking the pubsub client library from fetching more events. This is a balance between memory usage vs how efficiently the app can operate. The default value works well.
input.maxAckExtensionPeriod	Optional. Default value 1 hour. For how long the pubsub client library will continue to re-extend the ack deadline of an unprocessed event.
input.minDurationPerAckExtension	Optional. Default value 60 seconds. Sets min boundary on the value by which an ack deadline is extended. The actual value used is guided by runtime statistics collected by the pubsub client library.
input.maxDurationPerAckExtension	Optional. Default value 60 seconds. Sets max boundary on the value by which an ack deadline is extended. The actual value used is guided by runtime statistics collected by the pubsub client library.
output.bad.topic	Required, e.g. projects/myproject/topics/snowplow-bad. Name of the Pub/Sub topic that will receive failed events.
output.bad.batchSize	Optional. Default value 100. Bad events are sent to Pub/Sub in batches not exceeding this count.
output.bad.requestByteThreshold	Optional. Default value 1000000. Bad events are sent to Pub/Sub in batches with a total size not exceeding this byte threshold

Azure

Parameter	Description
input.topicName	Required. Name of the Kafka topic for the source of enriched events.
input.bootstrapServers	Required. Hostname and port of Kafka bootstrap servers hosting the source of enriched events.
input.consumerConf.*	Optional. A map of key/value pairs for any standard Kafka consumer configuration option.
output.bad.topicName	Required. Name of the Kafka topic that will receive failed events.
output.bad.bootstrapServers	Required. Hostname and port of Kafka bootstrap servers hosting the bad topic
output.bad.producerConf.*	Optional. A map of key/value pairs for any standard Kafka producer configuration option.

Event Hubs Authentication

You can use the input.consumerConf and output.bad.producerConf options to configure authentication to Azure event hubs using SASL. For example:

"input.consumerConf": {
    "security.protocol": "SASL_SSL"
    "sasl.mechanism": "PLAIN"
    "sasl.jaas.config": "org.apache.kafka.common.security.plain.PlainLoginModule required username=\"\$ConnectionString\" password=<PASSWORD>;"
}

Other configuration options

Parameter	Description
windowing	Optional. Default value 5 minutes. Controls how often the loader writes/commits pending events to the lake.
exitOnMissingIgluSchema	Optional. Default value true. Whether the loader should crash and exit if it fails to resolve an Iglu Schema. We recommend true because Snowplow enriched events have already passed validation, so a missing schema normally indicates an error that needs addressing. Change to false so events go the failed events stream instead of crashing the loader.
respectIgluNullability	Optional. Default value true. Whether the output parquet files should declare nested fields as non-nullable according to the Iglu schema. When true, nested fields are nullable only if they are not required fields according to the Iglu schema. When false, all nested fields are defined as nullable in the output table's schemas. Set this to false if you use a query engine that dislikes non-nullable nested fields of a nullable struct.
spark.conf.*	Optional. A map of key/value strings which are passed to the internal spark context.
spark.taskRetries	Optional. Default value 3. How many times the internal spark context should be retry a task in case of failure
retries.setupErrors.delay	Optional. Default value 30 seconds. Configures exponential backoff on errors related to how the lake is set up for this loader. Examples include authentication errors and permissions errors. This class of errors are reported periodically to the monitoring webhook.
retries.transientErrors.delay	Optional. Default value 1 second. Configures exponential backoff on errors that are likely to be transient. Examples include server errors and network errors.
retries.transientErrors.attempts	Optional. Default value 5. Maximum number of attempts to make before giving up on a transient error.
monitoring.metrics.statsd.hostname	Optional. If set, the loader sends statsd metrics over UDP to a server on this host name.
monitoring.metrics.statsd.port	Optional. Default value 8125. If the statsd server is configured, this UDP port is used for sending metrics.
monitoring.metrics.statsd.tags.*	Optional. A map of key/value pairs to be sent along with the statsd metric.
monitoring.metrics.statsd.period	Optional. Default 1 minute. How often to report metrics to statsd.
monitoring.metrics.statsd.prefix	Optional. Default snowplow.lakeloader. Prefix used for the metric name when sending to statsd.
monitoring.webhook.endpoint	Optional, e.g. https://webhook.example.com. The loader will send to the webhook a payload containing details of any error related to how Snowflake is set up for this loader.
monitoring.webhook.tags.*	Optional. A map of key/value strings to be included in the payload content sent to the webhook.
monitoring.webhook.heartbeat.*	Optional. Default value 5.minutes. How often to send a heartbeat event to the webhook when healthy.
monitoring.sentry.dsn	Optional. Set to a Sentry URI to report unexpected runtime exceptions.
monitoring.sentry.tags.*	Optional. A map of key/value strings which are passed as tags when reporting exceptions to Sentry.
telemetry.disable	Optional. Set to true to disable telemetry.
telemetry.userProvidedId	Optional. See here for more information.
inMemBatchBytes	Optional. Default value 50000000. Controls how many events are buffered in memory before saving the batch to local disk. The default value works well for reasonably sized VMs. For smaller VMs (e.g. less than 2 cpu core, 8 GG memory) consider decreasing this value.
cpuParallelismFactor	Optional. Default value 0.75. Controls how the app splits the workload into concurrent batches which can be run in parallel. E.g. If there are 4 available processors, and cpuParallelismFraction = 0.75, then we process 3 batches concurrently. The default value works well for most workloads.
numEagerWindows	Optional. Default value 1. Controls how eagerly the loader starts processing the next timed window even when the previous timed window is still finalizing (committing into the lake). By default, we start processing a timed windows if the previous 1 window is still finalizing, but we do not start processing a timed window if any more older windows are still finalizing. The default value works well for most workloads.
http.client.maxConnectionsPerServer	Optional. Default value 4. Configures the internal HTTP client used for Iglu resolver, alerts and telemetry. The maximum number of open HTTP requests to any single server at any one time. For Iglu Server in particular, this avoids overwhelming the server with multiple concurrent requests.