com.alipay.sofa.jraft.storage.snapshot

Class SnapshotExecutorImpl

java.lang.Object

com.alipay.sofa.jraft.storage.snapshot.SnapshotExecutorImpl

All Implemented Interfaces:

Lifecycle<SnapshotExecutorOptions>, SnapshotExecutor, Describer

public class SnapshotExecutorImpl
extends Object
implements SnapshotExecutor

Snapshot executor implementation.

Author:

boyan (boyan@alibaba-inc.com) 2018-Mar-22 5:38:56 PM

Nested Class Summary

Nested classes/interfaces inherited from interface com.alipay.sofa.jraft.util.Describer

Describer.DefaultPrinter, Describer.Printer

Constructor Summary

Constructors

Constructor and Description
SnapshotExecutorImpl()

Method Summary

Modifier and Type	Method and Description
void	describe(Describer.Printer out)
void	doSnapshot(Closure done) Start to snapshot StateMachine, and |done| is called after the execution finishes or fails.
void	doSnapshotSync(Closure done) Start to snapshot StateMachine immediately with the latest log applied to state machine.
long	getLastSnapshotIndex() Only for test
long	getLastSnapshotTerm() Only for test
NodeImpl	getNode() Return the owner NodeImpl
SnapshotStorage	getSnapshotStorage() Returns the backing snapshot storage
boolean	init(SnapshotExecutorOptions opts) Initialize the service.
void	installSnapshot(RpcRequests.InstallSnapshotRequest request, RpcRequests.InstallSnapshotResponse.Builder response, RpcRequestClosure done) Install snapshot according to the very RPC from leader After the installing succeeds (StateMachine is reset with the snapshot) or fails, done will be called to respond Errors: - Term mismatches: which happens interrupt_downloading_snapshot was called before install_snapshot, indicating that this RPC was issued by the old leader.
void	interruptDownloadingSnapshots(long newTerm) Interrupt the downloading if possible.
boolean	isInstallingSnapshot() Returns true if this is currently installing a snapshot, either downloading or loading.
void	join() Block the current thread until all the running job finishes (including failure)
void	shutdown() Dispose the resources for service.

Methods inherited from class java.lang.Object

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

Constructor Detail

SnapshotExecutorImpl

public SnapshotExecutorImpl()

Method Detail

getLastSnapshotTerm

@OnlyForTest
public long getLastSnapshotTerm()

Only for test

getLastSnapshotIndex

@OnlyForTest
public long getLastSnapshotIndex()

Only for test

init

public boolean init(SnapshotExecutorOptions opts)

Description copied from interface: Lifecycle

Initialize the service.

Specified by:

init in interface Lifecycle<SnapshotExecutorOptions>

Returns:

true when successes.

shutdown

public void shutdown()

Description copied from interface: Lifecycle

Dispose the resources for service.

Specified by:

shutdown in interface Lifecycle<SnapshotExecutorOptions>

getNode

public NodeImpl getNode()

Description copied from interface: SnapshotExecutor

Return the owner NodeImpl

Specified by:

getNode in interface SnapshotExecutor

doSnapshot

public void doSnapshot(Closure done)

Description copied from interface: SnapshotExecutor

Start to snapshot StateMachine, and |done| is called after the execution finishes or fails.

Specified by:

doSnapshot in interface SnapshotExecutor

Parameters:

done - snapshot callback

doSnapshotSync

public void doSnapshotSync(Closure done)

Description copied from interface: SnapshotExecutor

Start to snapshot StateMachine immediately with the latest log applied to state machine. You MUST call this method in StateMachine callback methods to trigger a snapshot synchronously, otherwise throws IllegalStateException. And |done| is called after the execution finishes or fails.

Specified by:

doSnapshotSync in interface SnapshotExecutor

Parameters:

done - snapshot callback

installSnapshot

public void installSnapshot(RpcRequests.InstallSnapshotRequest request,
                            RpcRequests.InstallSnapshotResponse.Builder response,
                            RpcRequestClosure done)

Description copied from interface: SnapshotExecutor

Install snapshot according to the very RPC from leader After the installing succeeds (StateMachine is reset with the snapshot) or fails, done will be called to respond Errors: - Term mismatches: which happens interrupt_downloading_snapshot was called before install_snapshot, indicating that this RPC was issued by the old leader. - Interrupted: happens when interrupt_downloading_snapshot is called or a new RPC with the same or newer snapshot arrives - Busy: the state machine is saving or loading snapshot

Specified by:

installSnapshot in interface SnapshotExecutor

interruptDownloadingSnapshots

public void interruptDownloadingSnapshots(long newTerm)

Description copied from interface: SnapshotExecutor

Interrupt the downloading if possible. This is called when the term of node increased to |new_term|, which happens when receiving RPC from new peer. In this case, it's hard to determine whether to keep downloading snapshot as the new leader possibly contains the missing logs and is going to send AppendEntries. To make things simplicity and leader changing during snapshot installing is very rare. So we interrupt snapshot downloading when leader changes, and let the new leader decide whether to install a new snapshot or continue appending log entries. NOTE: we can't interrupt the snapshot installing which has finished downloading and is reseting the State Machine.

Specified by:

interruptDownloadingSnapshots in interface SnapshotExecutor

Parameters:

newTerm - new term num

isInstallingSnapshot

public boolean isInstallingSnapshot()

Description copied from interface: SnapshotExecutor

Returns true if this is currently installing a snapshot, either downloading or loading.

Specified by:

isInstallingSnapshot in interface SnapshotExecutor

getSnapshotStorage

public SnapshotStorage getSnapshotStorage()

Description copied from interface: SnapshotExecutor

Returns the backing snapshot storage

Specified by:

getSnapshotStorage in interface SnapshotExecutor

join

public void join()
          throws InterruptedException

Description copied from interface: SnapshotExecutor

Block the current thread until all the running job finishes (including failure)

Specified by:

join in interface SnapshotExecutor

Throws:

InterruptedException

describe

public void describe(Describer.Printer out)

Specified by:

describe in interface Describer