org.apache.flume.channel

Class PseudoTxnMemoryChannel

java.lang.Object

org.apache.flume.channel.AbstractChannel

org.apache.flume.channel.PseudoTxnMemoryChannel

All Implemented Interfaces:

Channel, Configurable, LifecycleAware, NamedComponent

public class PseudoTxnMemoryChannel
extends AbstractChannel

A capacity-capped Channel implementation that supports in-memory buffering and delivery of events.

This channel is appropriate for best effort delivery of events where high throughput is favored over data durability. To be clear, this channel offers absolutely no guarantee of event delivery in the face of (any) component failure.

TODO: Discuss guarantees, corner cases re: potential data loss (e.g. consumer begins a tx, takes events, and gets SIGKILL before rollback).

Configuration options

Parameter	Description	Unit / Type	Default
capacity	The in-memory capacity of this channel. Store up to capacity events before refusing new events.	events / int	50
keep-alive	The amount of time (seconds) to wait for an event before returning null on take().	seconds / int	3

Metrics

TODO

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	PseudoTxnMemoryChannel.NoOpTransaction A no-op transaction implementation that does nothing at all.

Constructor Summary

Constructors

Constructor and Description
PseudoTxnMemoryChannel()

Method Summary

Methods

Modifier and Type	Method and Description
void	configure(Context context) Request the implementing class to (re)configure itself.
Transaction	getTransaction()
void	put(Event event) Puts the given event into the channel.
void	start() Starts a service or component.
void	stop() Stops a service or component.
Event	take() Returns the next event from the channel if available.

Methods inherited from class org.apache.flume.channel.AbstractChannel

getLifecycleState, getName, setName, toString

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

PseudoTxnMemoryChannel

public PseudoTxnMemoryChannel()

Method Detail

configure

public void configure(Context context)

Description copied from interface: Configurable

Request the implementing class to (re)configure itself.

When configuration parameters are changed, they must be reflected by the component asap.

There are no thread safety guarantees on when configure might be called.

Specified by:

configure in interface Configurable

Overrides:

configure in class AbstractChannel

start

public void start()

Description copied from interface: LifecycleAware

Starts a service or component.

Implementations should determine the result of any start logic and effect the return value of LifecycleAware.getLifecycleState() accordingly.

Specified by:

start in interface LifecycleAware

Overrides:

start in class AbstractChannel

stop

public void stop()

Description copied from interface: LifecycleAware

Stops a service or component.

Implementations should determine the result of any stop logic and effect the return value of LifecycleAware.getLifecycleState() accordingly.

Specified by:

stop in interface LifecycleAware

Overrides:

stop in class AbstractChannel

put

public void put(Event event)

Description copied from interface: Channel

Puts the given event into the channel.

Note: This method must be invoked within an active Transaction boundary. Failure to do so can lead to unpredictable results.

Parameters:

event - the event to transport.

See Also:

Transaction.begin()

take

public Event take()

Description copied from interface: Channel

Returns the next event from the channel if available. If the channel does not have any events available, this method must return null.

Note: This method must be invoked within an active Transaction boundary. Failure to do so can lead to unpredictable results.

Returns:

the next available event or null if no events are available.

See Also:

Transaction.begin()

getTransaction

public Transaction getTransaction()

Returns:

the transaction instance associated with this channel.