io.aeron.cluster.service

Class SnapshotTaker

java.lang.Object

io.aeron.cluster.service.SnapshotTaker

public class SnapshotTaker
extends Object

Base class of common functions required to take a snapshot of cluster state.

Field Summary

Fields

Modifier and Type	Field and Description
protected BufferClaim	bufferClaim Reusable BufferClaim to avoid allocation.
protected IdleStrategy	idleStrategy IdleStrategy to be called when back pressure is propagated from the publication.
protected MessageHeaderEncoder	messageHeaderEncoder Reusable MessageHeaderEncoder to avoid allocation.
protected ExclusivePublication	publication Publication to which the snapshot will be written.

Constructor Summary

Constructors

Constructor and Description
SnapshotTaker(ExclusivePublication publication, IdleStrategy idleStrategy, AgentInvoker aeronAgentInvoker) Construct a SnapshotTaker which will encode the snapshot to a publication.

Method Summary

Modifier and Type	Method and Description
protected static void	checkInterruptStatus() Check for thread interrupt and throw an AgentTerminationException if interrupted.
protected static void	checkResult(long result) Check the result of offering to a publication when writing a snapshot.
protected void	checkResultAndIdle(long result) Check the result of offering to a publication when writing a snapshot and then idle after invoking the client agent if necessary.
protected void	invokeAgentClient() Invoke the Aeron client agent if necessary.
void	markBegin(long snapshotTypeId, long logPosition, long leadershipTermId, int snapshotIndex, TimeUnit timeUnit, int appVersion) Mark the beginning of the encoded snapshot.
void	markEnd(long snapshotTypeId, long logPosition, long leadershipTermId, int snapshotIndex, TimeUnit timeUnit, int appVersion) Mark the end of the encoded snapshot.
void	markSnapshot(long snapshotTypeId, long logPosition, long leadershipTermId, int snapshotIndex, SnapshotMark snapshotMark, TimeUnit timeUnit, int appVersion) Generically SnapshotMark a snapshot.
protected void	offer(DirectBuffer buffer, int offset, int length) Helper method to offer a message into the snapshot publication.

Methods inherited from class java.lang.Object

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

Field Detail

bufferClaim

protected final BufferClaim bufferClaim

Reusable BufferClaim to avoid allocation.

messageHeaderEncoder

protected final MessageHeaderEncoder messageHeaderEncoder

Reusable MessageHeaderEncoder to avoid allocation.

publication

protected final ExclusivePublication publication

Publication to which the snapshot will be written.

idleStrategy

protected final IdleStrategy idleStrategy

IdleStrategy to be called when back pressure is propagated from the publication.

Constructor Detail

SnapshotTaker

public SnapshotTaker(ExclusivePublication publication,
                     IdleStrategy idleStrategy,
                     AgentInvoker aeronAgentInvoker)

Construct a SnapshotTaker which will encode the snapshot to a publication.

Parameters:

publication - into which the snapshot will be encoded.

idleStrategy - to call when the publication is back pressured.

aeronAgentInvoker - to call when idling so it stays active.

Method Detail

markBegin

public void markBegin(long snapshotTypeId,
                      long logPosition,
                      long leadershipTermId,
                      int snapshotIndex,
                      TimeUnit timeUnit,
                      int appVersion)

Mark the beginning of the encoded snapshot.

Parameters:

snapshotTypeId - type to identify snapshot within a cluster.

logPosition - at which the snapshot was taken.

leadershipTermId - at which the snapshot was taken.

snapshotIndex - so the snapshot can be sectioned.

timeUnit - of the cluster timestamps stored in the snapshot.

appVersion - associated with the snapshot from ClusteredServiceContainer.Context.appVersion().

markEnd

public void markEnd(long snapshotTypeId,
                    long logPosition,
                    long leadershipTermId,
                    int snapshotIndex,
                    TimeUnit timeUnit,
                    int appVersion)

Mark the end of the encoded snapshot.

Parameters:

snapshotTypeId - type to identify snapshot within a cluster.

logPosition - at which the snapshot was taken.

leadershipTermId - at which the snapshot was taken.

snapshotIndex - so the snapshot can be sectioned.

timeUnit - of the cluster timestamps stored in the snapshot.

appVersion - associated with the snapshot from ClusteredServiceContainer.Context.appVersion().

markSnapshot

public void markSnapshot(long snapshotTypeId,
                         long logPosition,
                         long leadershipTermId,
                         int snapshotIndex,
                         SnapshotMark snapshotMark,
                         TimeUnit timeUnit,
                         int appVersion)

Generically SnapshotMark a snapshot.

Parameters:

snapshotTypeId - type to identify snapshot within a cluster.

logPosition - at which the snapshot was taken.

leadershipTermId - at which the snapshot was taken.

snapshotIndex - so the snapshot can be sectioned.

snapshotMark - which specifies the type of snapshot mark.

timeUnit - of the cluster timestamps stored in the snapshot.

appVersion - associated with the snapshot from ClusteredServiceContainer.Context.appVersion().

checkInterruptStatus

protected static void checkInterruptStatus()

Check for thread interrupt and throw an AgentTerminationException if interrupted.

checkResult

protected static void checkResult(long result)

Check the result of offering to a publication when writing a snapshot.

Parameters:

result - of an offer or try claim to a publication.

checkResultAndIdle

protected void checkResultAndIdle(long result)

Check the result of offering to a publication when writing a snapshot and then idle after invoking the client agent if necessary.

Parameters:

result - of an offer or try claim to a publication.

invokeAgentClient

protected void invokeAgentClient()

Invoke the Aeron client agent if necessary.

offer

protected final void offer(DirectBuffer buffer,
                           int offset,
                           int length)

Helper method to offer a message into the snapshot publication.

Parameters:

buffer - containing the message.

offset - at which the message begins.

length - of the message.