io.zeebe.logstreams.log.LogStream Maven / Gradle / Ivy
/*
* Copyright © 2017 camunda services GmbH ([email protected])
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package io.zeebe.logstreams.log;
import io.zeebe.dispatcher.Dispatcher;
import io.zeebe.logstreams.impl.LogBlockIndexWriter;
import io.zeebe.logstreams.impl.LogStorageAppender;
import io.zeebe.logstreams.impl.log.index.LogBlockIndex;
import io.zeebe.logstreams.spi.LogStorage;
import io.zeebe.util.sched.ActorCondition;
import io.zeebe.util.sched.future.ActorFuture;
/**
* Represents a stream of events from a log storage.
*
* Opening the log stream will start the indexing of the current existing log storage. The log
* storage will separated into blocks, these blocks will be indexed by an LogController. The
* LogBlockIndex is available and can be accessed via {@link LogStream#getLogBlockIndex()}.
*
*
The LogStream will append available events to the log storage with the help of an
* LogController. The events are read from a given Dispatcher, if available. This can be stopped
* with the {@link LogStream#closeAppender()} method and re-/started with {@link
* LogStream#openLogStreamController(AgentRunnerService)} or {@link
* LogStream#openLogStreamController(AgentRunnerService, int)}.
*
*
To access the current LogStorage the {@link LogStream#getLogStorage()} can be used. The {@link
* #close()} method will close all LogController and the log storage.
*/
public interface LogStream extends AutoCloseable {
int DEFAULT_MAX_APPEND_BLOCK_SIZE = 1024 * 1024 * 4;
/** @return the partition id of the log stream */
int getPartitionId();
/**
* Returns the name of the log stream.
*
* @return the log stream name
*/
String getLogName();
/** Closes the log stream synchronously. This blocks until the log stream is closed. */
@Override
void close();
/** Closes the log stream asynchronous. */
ActorFuture closeAsync();
/** @return the current commit position, or a negative value if no entry is committed. */
long getCommitPosition();
/** Sets the log streams commit position to the given position. */
void setCommitPosition(long commitPosition);
/** @return the current term in which the log stream is active */
int getTerm();
/** Sets the log streams term. */
void setTerm(int term);
/**
* Returns the log storage, which is accessed by the LogStream.
*
* @return the log storage
*/
LogStorage getLogStorage();
/**
* Returns the LogBlockIndex object, which is used for indexing the LogStorage.
*
* @return the log block index
*/
LogBlockIndex getLogBlockIndex();
/**
* Returns the writeBuffer, which is used by the LogStreamController to stream the content into
* the log storage.
*
* @return the writebuffer, which is used by the LogStreamController
*/
Dispatcher getWriteBuffer();
/**
* Returns the log stream controller, which streams the logged events from the write buffer into
* the log storage.
*
* @return the log stream controller
*/
LogStorageAppender getLogStorageAppender();
/**
* Returns the log block index controller, which creates periodically the block index for the log
* storage.
*
* @return the log block index controller
*/
LogBlockIndexWriter getLogBlockIndexWriter();
/** Stops the streaming to the log storage. New events are no longer append to the log storage. */
ActorFuture closeAppender();
/**
* This method delegates to {@link #openLogStreamController(AgentRunnerService, int)}.
*
* The {@link #DEFAULT_MAX_APPEND_BLOCK_SIZE} is used as default max append block size and the
* old agent runner service is reused.
*
* @see {@link #openLogStreamController(AgentRunnerService, int)}
* @return returns the future for the log stream controller opening
*/
ActorFuture openAppender();
/**
* Truncates the log stream from the given position to the end of the stream. Each event which has
* a higher position as the given will be truncated. This method will truncated the log storage
* and block index.
*
* @param position the position to start the truncation
* @return the future which is completed if the truncation was successful
*/
void truncate(long position);
void registerOnCommitPositionUpdatedCondition(ActorCondition condition);
void removeOnCommitPositionUpdatedCondition(ActorCondition condition);
void registerOnAppendCondition(ActorCondition condition);
void removeOnAppendCondition(ActorCondition condition);
}