io.atomix.protocols.raft.storage

Class RaftStorage.Builder

java.lang.Object

io.atomix.protocols.raft.storage.RaftStorage.Builder

All Implemented Interfaces:

io.atomix.utils.Builder<RaftStorage>

Enclosing class:

RaftStorage

public static class RaftStorage.Builder
extends Object
implements io.atomix.utils.Builder<RaftStorage>

Builds a RaftStorage configuration.

The storage builder provides simplifies building more complex RaftStorage configurations. To create a storage builder, use the RaftStorage.newBuilder() factory method. Set properties of the configured Storage object with the various with* methods. Once the storage has been configured, call build() to build the object.

   
   Storage storage = Storage.builder()
     .withDirectory(new File("logs"))
     .withPersistenceLevel(PersistenceLevel.DISK)
     .build();
   
 

Method Summary

Modifier and Type	Method and Description
RaftStorage	build() Builds the RaftStorage object.
RaftStorage.Builder	withDirectory(File directory) Sets the log directory, returning the builder for method chaining.
RaftStorage.Builder	withDirectory(String directory) Sets the log directory, returning the builder for method chaining.
RaftStorage.Builder	withDynamicCompaction() Enables dynamic log compaction.
RaftStorage.Builder	withDynamicCompaction(boolean dynamicCompaction) Enables dynamic log compaction.
RaftStorage.Builder	withFlushOnCommit() Enables flushing buffers to disk when entries are committed to a segment, returning the builder for method chaining.
RaftStorage.Builder	withFlushOnCommit(boolean flushOnCommit) Sets whether to flush buffers to disk when entries are committed to a segment, returning the builder for method chaining.
RaftStorage.Builder	withFreeDiskBuffer(double freeDiskBuffer) Sets the percentage of free disk space that must be preserved before log compaction is forced.
RaftStorage.Builder	withMaxEntriesPerSegment(int maxEntriesPerSegment) Sets the maximum number of allows entries per segment, returning the builder for method chaining.
RaftStorage.Builder	withMaxSegmentSize(int maxSegmentSize) Sets the maximum segment size in bytes, returning the builder for method chaining.
RaftStorage.Builder	withPrefix(String prefix) Sets the storage prefix.
RaftStorage.Builder	withRetainStaleSnapshots() Enables retaining stale snapshots on disk, returning the builder for method chaining.
RaftStorage.Builder	withRetainStaleSnapshots(boolean retainStaleSnapshots) Sets whether to retain stale snapshots on disk, returning the builder for method chaining.
RaftStorage.Builder	withSerializer(io.atomix.serializer.Serializer serializer) Sets the storage serializer.
RaftStorage.Builder	withStorageLevel(io.atomix.storage.StorageLevel storageLevel) Sets the log storage level, returning the builder for method chaining.

Methods inherited from class java.lang.Object

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

Method Detail

withPrefix

public RaftStorage.Builder withPrefix(String prefix)

Sets the storage prefix.

Parameters:

prefix - The storage prefix.

Returns:

The storage builder.

withStorageLevel

public RaftStorage.Builder withStorageLevel(io.atomix.storage.StorageLevel storageLevel)

Sets the log storage level, returning the builder for method chaining.

The storage level indicates how individual entries should be persisted in the log.

Parameters:

storageLevel - The log storage level.

Returns:

The storage builder.

withDirectory

public RaftStorage.Builder withDirectory(String directory)

Sets the log directory, returning the builder for method chaining.

The log will write segment files into the provided directory. If multiple RaftStorage objects are located on the same machine, they write logs to different directories.

Parameters:

directory - The log directory.

Returns:

The storage builder.

Throws:

NullPointerException - If the directory is null

withDirectory

public RaftStorage.Builder withDirectory(File directory)

Sets the log directory, returning the builder for method chaining.

The log will write segment files into the provided directory. If multiple RaftStorage objects are located on the same machine, they write logs to different directories.

Parameters:

directory - The log directory.

Returns:

The storage builder.

Throws:

NullPointerException - If the directory is null

withSerializer

public RaftStorage.Builder withSerializer(io.atomix.serializer.Serializer serializer)

Sets the storage serializer.

Parameters:

serializer - The storage serializer.

Returns:

The storage builder.

Throws:

NullPointerException - If the serializer is null

withMaxSegmentSize

public RaftStorage.Builder withMaxSegmentSize(int maxSegmentSize)

Sets the maximum segment size in bytes, returning the builder for method chaining.

The maximum segment size dictates when logs should roll over to new segments. As entries are written to a segment of the log, once the size of the segment surpasses the configured maximum segment size, the log will create a new segment and append new entries to that segment.

By default, the maximum segment size is 1024 * 1024 * 32.

Parameters:

maxSegmentSize - The maximum segment size in bytes.

Returns:

The storage builder.

Throws:

IllegalArgumentException - If the maxSegmentSize is not positive

withMaxEntriesPerSegment

public RaftStorage.Builder withMaxEntriesPerSegment(int maxEntriesPerSegment)

Sets the maximum number of allows entries per segment, returning the builder for method chaining.

The maximum entry count dictates when logs should roll over to new segments. As entries are written to a segment of the log, if the entry count in that segment meets the configured maximum entry count, the log will create a new segment and append new entries to that segment.

By default, the maximum entries per segment is 1024 * 1024.

Parameters:

maxEntriesPerSegment - The maximum number of entries allowed per segment.

Returns:

The storage builder.

Throws:

IllegalArgumentException - If the maxEntriesPerSegment not greater than the default max entries per segment

withDynamicCompaction

public RaftStorage.Builder withDynamicCompaction()

Enables dynamic log compaction.

When dynamic compaction is enabled, logs will be compacted only during periods of low load on the cluster or when the cluster is running out of disk space.

Returns:

the Raft storage builder

withDynamicCompaction

public RaftStorage.Builder withDynamicCompaction(boolean dynamicCompaction)

Enables dynamic log compaction.

When dynamic compaction is enabled, logs will be compacted only during periods of low load on the cluster or when the cluster is running out of disk space.

Parameters:

dynamicCompaction - whether to enable dynamic compaction

Returns:

the Raft storage builder

withFreeDiskBuffer

public RaftStorage.Builder withFreeDiskBuffer(double freeDiskBuffer)

Sets the percentage of free disk space that must be preserved before log compaction is forced.

Parameters:

freeDiskBuffer - the free disk percentage

Returns:

the Raft log builder

withFlushOnCommit

public RaftStorage.Builder withFlushOnCommit()

Enables flushing buffers to disk when entries are committed to a segment, returning the builder for method chaining.

When flush-on-commit is enabled, log entry buffers will be automatically flushed to disk each time an entry is committed in a given segment.

Returns:

The storage builder.

withFlushOnCommit

public RaftStorage.Builder withFlushOnCommit(boolean flushOnCommit)

Sets whether to flush buffers to disk when entries are committed to a segment, returning the builder for method chaining.

When flush-on-commit is enabled, log entry buffers will be automatically flushed to disk each time an entry is committed in a given segment.

Parameters:

flushOnCommit - Whether to flush buffers to disk when entries are committed to a segment.

Returns:

The storage builder.

withRetainStaleSnapshots

public RaftStorage.Builder withRetainStaleSnapshots()

Enables retaining stale snapshots on disk, returning the builder for method chaining.

As the system state progresses, periodic snapshots of the state machine's state are taken. Once a new snapshot of the state machine is taken, all preceding snapshots no longer contribute to the state of the system and can therefore be removed from disk. By default, snapshots will not be retained once a new snapshot is stored on disk. Enabling snapshot retention will ensure that all snapshots will be saved, e.g. for backup purposes.

Returns:

The storage builder.

withRetainStaleSnapshots

public RaftStorage.Builder withRetainStaleSnapshots(boolean retainStaleSnapshots)

Sets whether to retain stale snapshots on disk, returning the builder for method chaining.

As the system state progresses, periodic snapshots of the state machine's state are taken. Once a new snapshot of the state machine is taken, all preceding snapshots no longer contribute to the state of the system and can therefore be removed from disk. By default, snapshots will not be retained once a new snapshot is stored on disk. Enabling snapshot retention will ensure that all snapshots will be saved, e.g. for backup purposes.

Parameters:

retainStaleSnapshots - Whether to retain stale snapshots on disk.

Returns:

The storage builder.

build

public RaftStorage build()

Builds the RaftStorage object.

Specified by:

build in interface io.atomix.utils.Builder<RaftStorage>

Returns:

The built storage configuration.