Flow Handlers

Flow handlers are included in all Rierino platform versions, providing ability to combine and orchestrate various actions

Flow handlers coordinate orchestration logic across events, steps, roles, and streams.

Use this page for handler-level details:

• Class names

• Handler parameters

• Runtime dependencies

• Roles and commands

Use Flow Actions for action-level saga step fields and parameters.

Orchestrate Saga

Class: com.rierino.handler.saga.SagaEventHandler

Coordinates end-to-end saga execution across local or distributed runners.

Handler parameters

Parameter	Definition	Example	Default
saga.state	State manager keeping saga definitions	customSaga	saga
response.stream	Stream used for saga completion or failure results	response_product	response
saga.stream	Stream used to track saga step results	saga_product	saga
saga.system	System used to track saga step results	kafka_default	-
event.system	Default system used to post requests to event runners	kafka_default	-
saga.timeout	Timeout in milliseconds for saga calls	5000	10000
timer.pool	Thread count for scheduled sagas	10	-
roles.variable	Variable name used for allowed role matching	userRoles	user.roles path in payload
offset.state	State manager used for storing offsets for "self waiting" sagas	cdc_offset	-
offset.partitioned	Whether offsets are stored as partitioned (i.e. multiple replicas running as saga CDC)	true	false

Action details: Orchestrate Saga

Execute Predefined Actions

Class: com.rierino.handler.ActionEventHandler

Executes reusable predefined actions as part of a saga flow.

Handler parameters

Parameter	Definition	Example	Default
action.state	State manager keeping action records	custom_action	action

Action details: Execute Predefined Actions

Loop Each Entry

Class: com.rierino.handler.ForEachEventHandler

Repeats an action for each entry in a payload array.

Handler parameters

This handler requires no parameters.

Action details: Loop Each Entry

Run Multiple Steps

Class: com.rierino.handler.CompositeEventHandler

Runs multiple actions in sequence and passes the output of each step to the next.

Handler parameters

This handler requires no parameters.

Action details: Run Multiple Steps

Buffer Payloads

Class: com.rierino.handler.BufferEventHandler

Buffers multiple incoming payloads and emits them as a single batch.

Handler parameters

This handler requires no parameters.

Action details: Buffer Payloads

Merge Parallel Steps

Class: com.rierino.handler.MergeEventHandler

Waits for parallel branches to complete, then merges their results and continues the flow.

Handler parameters

Parameter	Definition	Example	Default
merge.locker	Locker class used for thread-safe merge coordination	com.rierino.state.lock.RedisStateLocker	-
merge.locker.timeout	Milliseconds to wait for acquiring a lock	1000	-
merge.action	What to do with the merge state record on completion	delete	update
merge.locker.expiry	Lock TTL in milliseconds	10000	-1

This handler also supports timeout-oriented task controls for merge activities.

Action details: Merge Parallel Steps

Log Event

Class: com.rierino.handler.LogEventHandler

Logs event or payload contents for debugging and tracing.

Handler parameters

This handler requires no parameters.

Action details: Log Event

Send Event

Class: com.rierino.handler.SendEventHandler

Sends an event to another stream.

Handler parameters

This handler requires no parameters.

Action details: Send Event

Validate Event

Class: com.rierino.handler.ValidationEventHandler

Validates event input using a configured validator.

Handler parameters

Parameter	Definition	Example	Default
validator	Fully qualified validator class name	com.rierino.handler.util.validator.JsonSchemaValidator	-
validator.*	Additional validator class parameters	state=schema	-

Built-in validators

• JMESValidator

• JsonSchemaValidator

Action details: Validate Event

Transform Event

Class: com.rierino.handler.TransformEventHandler

Applies a transformation class to an incoming event payload.

Handler parameters

This handler requires no parameters.

Action details: Transform Event

Lock & Unlock

Class: com.rierino.handler.LockEventHandler

Creates, checks, and releases locks for a given domain and id.

Handler parameters

Parameter	Definition	Example	Default
locker	StateLocker class used to issue and release locks	com.rierino.state.lock.RedisStateLocker	-
timeout	Default milliseconds to wait for acquiring a lock	1000	-
expiry	Default TTL of a lock in milliseconds	60000	-1

Action details: Lock & Unlock

Perform DB Transaction

Class: com.rierino.handler.JDBCTransactionEventHandler

Executes multiple JDBC state changes as a single transaction.

Handler parameters

Parameter	Definition	Example	Default
transaction.timeout	Seconds before a transaction is considered timed out	60	20

Runtime dependency

implementation (group:'com.rierino.processors', name: 'jdbc', version:"${rierinoVersion}")

Action details: Perform DB Transaction

Trigger Runner Command

Class: com.rierino.handler.CommandEventHandler

Executes a runner command from an event payload. This is mainly used for development or simple single-runner setups.

Handler parameters

This handler requires no parameters.

Action details: Trigger Runner Command

Do Nothing

Class: com.rierino.handler.NoopEventHandler

Passes event or role data through without modification.

Handler parameters

This handler requires no parameters.

Roles

• noop

Action details: Do Nothing

Modify Role Data

Class: com.rierino.handler.JMESDataRoleHandler

Transforms and routes role data using a JMESPath pattern.

Handler parameters

Parameter	Definition	Example	Default
pattern	JMESPath pattern with data, route, and filter details	[{ "data":@, "route":{"system":'kafka',"stream":'customer',"key":payload.customer.id}, "filter":payload.customer.id!=null }]	-

Roles

• processData

Enrich Role Data

Class: com.rierino.handler.ConversionRoleHandler

Enriches or converts pulse and journal records using state or query data.

Handler parameters

Parameter	Definition	Example	Default
source.state	State manager used to enrich data	product	-
output.journal	Stream used to send outputs	variant_journal	-
trigger.state	State manager whose changes trigger outputs	product_local	-
query.state	State manager keeping query records	query	-
query.id	Query id used for enrichment	variant_query	-
buffer	Number of records buffered before sending	100	-
reload	Whether handler allows reload from source	false	true
journalAction	Journal action used for source feeds	CREATE	UPSERT

Roles

• conversionPulse

• conversionJournal

Commands

• FULLRELOAD

• OFFSETRELOAD

• IDRELOAD

Convert Pulse to Journal

Class: com.rierino.handler.CDCRoleHandler

Converts CDC pulse records into journal entries and enriches them from state data.

Handler parameters

Parameter	Definition	Example	Default
cdc.state	State manager used to produce journal data	product	-
allowExternal	Allow externally originated pulses without journal records	true	false

Roles

• produceJournal