Function Blocks for Agents in Batch Workflows

The function blocks described in this section can only be used in Python agents in batch workflows. The available function blocks are:

  • beginBatch

  • drain

  • endBatch

  • endBatchHinted

  • cancelBatch

  • splittingBatch

  • commit

  • rollback

beginBatch

Note!

This function block only applies for the Python processing agent.

This function block is executed at the beginning of each batch.

def beginBatch()

Example - beginBatch function block


def beginBatch():
    debug('beginBatch called')


drain

Note!

This function block only applies for the Python processing agent.

This function block is called before the current batch ends. The agent must flush all internal buffers to make sure all pending data has been processed before the transaction is ended. This method is the last point in the batch processing where the agent is permitted to route data.

def drain()


Example - drain function block


def drain():
    debug('drain called')
    udrRoute(myLastUDR) 


endBatch 

Note!

This function block only applies for the Python processing agent.

This function block is executed at the end of each batch.

def endBatch()

example - endBatch function block


def endBatch():
    debug('endBatch called')


endBatchHinted

Note!

This function block only applies for the Python collection agent.

This function block is called when another agent has called hintEndBatch. The collection agent may choose to ignore this method, that is, not to implement it if it cannot be supported.

def endBatchHinted()

Example - endBatchHinted function block


def endBatchHinted():
    debug('endBatchHinted called')


cancelBatch

This function block is executed if a Cancel Batch is emitted anywhere in the workflow.

def cancelBatch()

Exampel - cancelBatch function block


def cancelBatch():
    debug('cancelBatch called')


splittingBatch

Note!

This function block only applies for the Python processing agent.

This function block is called when the collection agent has split the input batch. If the agent keeps internal buffers to be flushed differently depending on the nature of the transaction, this method serves as a hint to the drain call.

def splittingBatch()

Example - splittingBatch function block


def splittingBatch():
    debug('splittingBatch called')


commit

This function block is executed for each batch when the transaction is successful. If the commit block fails with an exception, it will be executed again until it succeeds.

def commit()

Example - commit function block


isRecoveryCommit = True

def initialize():
    debug('initialize called')

def beginBatch():
    global isRecoveryCommit
    isRecoveryCommit = False

def commit():
    if isRecoveryCommit:
        debug('this is a recovery commit, it is executed immediately after initialize')
    else:
        debug('this is a normal commit')


rollback

This function block is executed for a batch if it fails.

def rollback()

Example - rollback function block


def rollback():
    debug('rollback called')