io.aeron.cluster.service

Class ClusterMarkFile

java.lang.Object

io.aeron.cluster.service.ClusterMarkFile

All Implemented Interfaces:

AutoCloseable

public final class ClusterMarkFile
extends Object
implements AutoCloseable

Used to indicate if a cluster service is running and what configuration it is using. Errors encountered by the service are recorded within this file by a DistinctErrorLog.

Field Summary

Fields

Modifier and Type	Field and Description
static String	FILE_EXTENSION
static String	FILENAME
static int	HEADER_LENGTH
static int	MAJOR_VERSION
static int	MINOR_VERSION
static int	PATCH_VERSION
static int	SEMANTIC_VERSION
static String	SERVICE_FILENAME_PREFIX
static int	VERSION_FAILED

Constructor Summary

Constructors

Constructor and Description
ClusterMarkFile(File file, ClusterComponentType type, int errorBufferLength, EpochClock epochClock, long timeoutMs) Create new MarkFile for a cluster service but check if an existing service is active.
ClusterMarkFile(File directory, String filename, EpochClock epochClock, long timeoutMs, Consumer<String> logger) Construct to read the status of an existing MarkFile for a cluster component.

Method Summary

Modifier and Type	Method and Description
long	activityTimestampVolatile() Read the activity timestamp of the cluster component with volatile semantics.
long	candidateTermId() Get the current value of a candidate term id if a vote is placed in an election.
void	candidateTermId(long candidateTermId, int fileSyncLevel) Record the fact that a node has voted in a current election for a candidate so it can survive a restart.
static void	checkHeaderLength(String aeronDirectory, String controlChannel, String ingressChannel, String serviceName, String authenticator) Check if the header length is sufficient for encoding the provided properties.
void	close()
int	clusterId() Identity of the cluster instance so multiple clusters can run on the same driver.
void	clusterId(int clusterId) Identity of the cluster instance so multiple clusters can run on the same driver.
MarkFileHeaderDecoder	decoder() The decoder for reading the MarkFile header.
MarkFileHeaderEncoder	encoder() The encoder for writing the MarkFile header.
AtomicBuffer	errorBuffer() The direct buffer which wraps the region of the MarkFile which contains the error log.
ClusterNodeControlProperties	loadControlProperties() The control properties for communicating between the consensus module and the services.
static String	markFilenameForService(int serviceId) The filename to be used for the mark file given a service id.
int	memberId() Cluster member id either assigned statically or as the result of dynamic membership join.
void	memberId(int memberId) Member id assigned as part of dynamic join of a cluster.
static void	saveExistingErrors(File markFile, AtomicBuffer errorBuffer, PrintStream logger) Save the existing errors from a MarkFile to a PrintStream for logging.
void	signalFailedStart() Signal the cluster component has failed to conclude and cannot start.
void	signalReady() Signal the cluster component has concluded successfully and ready to start.
void	updateActivityTimestamp(long nowMs) Update the activity timestamp as a proof of life.

Methods inherited from class java.lang.Object

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

Field Detail

MAJOR_VERSION

public static final int MAJOR_VERSION

See Also:

Constant Field Values

MINOR_VERSION

public static final int MINOR_VERSION

See Also:

Constant Field Values

PATCH_VERSION

public static final int PATCH_VERSION

See Also:

Constant Field Values

SEMANTIC_VERSION

public static final int SEMANTIC_VERSION

HEADER_LENGTH

public static final int HEADER_LENGTH

See Also:

Constant Field Values

VERSION_FAILED

public static final int VERSION_FAILED

See Also:

Constant Field Values

FILE_EXTENSION

public static final String FILE_EXTENSION

See Also:

Constant Field Values

FILENAME

public static final String FILENAME

See Also:

Constant Field Values

SERVICE_FILENAME_PREFIX

public static final String SERVICE_FILENAME_PREFIX

See Also:

Constant Field Values

Constructor Detail

ClusterMarkFile

public ClusterMarkFile(File file,
                       ClusterComponentType type,
                       int errorBufferLength,
                       EpochClock epochClock,
                       long timeoutMs)

Create new MarkFile for a cluster service but check if an existing service is active.

Parameters:

file - full qualified file to the MarkFile.

type - of cluster component the MarkFile represents.

errorBufferLength - for storing the error log.

epochClock - for checking liveness against.

timeoutMs - for the activity check on an existing MarkFile.

ClusterMarkFile

public ClusterMarkFile(File directory,
                       String filename,
                       EpochClock epochClock,
                       long timeoutMs,
                       Consumer<String> logger)

Construct to read the status of an existing MarkFile for a cluster component.

Parameters:

directory - in which the mark file exists.

filename - for the MarkFile.

epochClock - to be used for checking liveness.

timeoutMs - to wait for file to exist.

logger - to which debug information will be written if an issue occurs.

Method Detail

close

public void close()

Specified by:

close in interface AutoCloseable

candidateTermId

public long candidateTermId()

Get the current value of a candidate term id if a vote is placed in an election.

Returns:

the current candidate term id within an election after voting or Aeron.NULL_VALUE if no voting phase of an election is currently active.

candidateTermId

public void candidateTermId(long candidateTermId,
                            int fileSyncLevel)

Record the fact that a node has voted in a current election for a candidate so it can survive a restart.

Parameters:

candidateTermId - to record that a vote has taken place.

fileSyncLevel - as defined by cluster file sync level.

memberId

public int memberId()

Cluster member id either assigned statically or as the result of dynamic membership join.

Returns:

cluster member id either assigned statically or as the result of dynamic membership join.

memberId

public void memberId(int memberId)

Member id assigned as part of dynamic join of a cluster.

Parameters:

memberId - assigned as part of dynamic join of a cluster.

clusterId

public int clusterId()

Identity of the cluster instance so multiple clusters can run on the same driver.

Returns:

id of the cluster instance so multiple clusters can run on the same driver.

clusterId

public void clusterId(int clusterId)

Identity of the cluster instance so multiple clusters can run on the same driver.

Parameters:

clusterId - of the cluster instance so multiple clusters can run on the same driver.

signalReady

public void signalReady()

Signal the cluster component has concluded successfully and ready to start.

signalFailedStart

public void signalFailedStart()

Signal the cluster component has failed to conclude and cannot start.

updateActivityTimestamp

public void updateActivityTimestamp(long nowMs)

Update the activity timestamp as a proof of life.

Parameters:

nowMs - activity timestamp as a proof of life.

activityTimestampVolatile

public long activityTimestampVolatile()

Read the activity timestamp of the cluster component with volatile semantics.

Returns:

the activity timestamp of the cluster component with volatile semantics.

encoder

public MarkFileHeaderEncoder encoder()

The encoder for writing the MarkFile header.

Returns:

the encoder for writing the MarkFile header.

decoder

public MarkFileHeaderDecoder decoder()

The decoder for reading the MarkFile header.

Returns:

the decoder for reading the MarkFile header.

errorBuffer

public AtomicBuffer errorBuffer()

The direct buffer which wraps the region of the MarkFile which contains the error log.

Returns:

the direct buffer which wraps the region of the MarkFile which contains the error log.

saveExistingErrors

public static void saveExistingErrors(File markFile,
                                      AtomicBuffer errorBuffer,
                                      PrintStream logger)

Save the existing errors from a MarkFile to a PrintStream for logging.

Parameters:

markFile - which contains the error buffer.

errorBuffer - which wraps the error log.

logger - to which the existing errors will be printed.

checkHeaderLength

public static void checkHeaderLength(String aeronDirectory,
                                     String controlChannel,
                                     String ingressChannel,
                                     String serviceName,
                                     String authenticator)

Check if the header length is sufficient for encoding the provided properties.

Parameters:

aeronDirectory - for the media driver.

controlChannel - for the consensus module.

ingressChannel - from the cluster clients.

serviceName - for the application service.

authenticator - for the application service.

markFilenameForService

public static String markFilenameForService(int serviceId)

The filename to be used for the mark file given a service id.

Parameters:

serviceId - of the service the ClusterMarkFile represents.

Returns:

the filename to be used for the mark file given a service id.

loadControlProperties

public ClusterNodeControlProperties loadControlProperties()

The control properties for communicating between the consensus module and the services.

Returns:

the control properties for communicating between the consensus module and the services.