software.amazon.jdbc.plugin.failover

Class ClusterAwareReaderFailoverHandler

java.lang.Object

software.amazon.jdbc.plugin.failover.ClusterAwareReaderFailoverHandler

All Implemented Interfaces:

ReaderFailoverHandler

public class ClusterAwareReaderFailoverHandler
extends java.lang.Object
implements ReaderFailoverHandler

An implementation of ReaderFailoverHandler.

Reader Failover Process goal is to connect to any available reader. In order to connect faster, this implementation tries to connect to two readers at the same time. The first successfully connected reader is returned as the process result. If both readers are unavailable (i.e. could not be connected to), the process picks up another pair of readers and repeat. If no reader has been connected to, the process may consider a writer host, and other hosts marked down, to connect to.

Field Summary

Fields

Modifier and Type	Field and Description
protected static int	DEFAULT_FAILOVER_TIMEOUT
protected static int	DEFAULT_READER_CONNECT_TIMEOUT
protected static ReaderFailoverResult	FAILED_READER_FAILOVER_RESULT
protected java.util.Map<java.lang.String,HostAvailability>	hostAvailabilityMap
protected boolean	isStrictReaderRequired
protected int	maxFailoverTimeoutMs
protected PluginService	pluginService
protected java.util.Properties	props
protected FullServicesContainer	servicesContainer
protected int	timeoutMs

Constructor Summary

Constructors

Constructor and Description
ClusterAwareReaderFailoverHandler(FullServicesContainer servicesContainer, java.util.Properties props) ClusterAwareReaderFailoverHandler constructor.
ClusterAwareReaderFailoverHandler(FullServicesContainer servicesContainer, java.util.Properties props, int maxFailoverTimeoutMs, int timeoutMs, boolean isStrictReaderRequired) ClusterAwareReaderFailoverHandler constructor.

Method Summary

Modifier and Type	Method and Description
ReaderFailoverResult	failover(java.util.List<HostSpec> hosts, HostSpec currentHost) Called to start Reader Failover Process.
protected ReaderFailoverResult	failoverInternal(java.util.List<HostSpec> hosts, HostSpec currentHost)
java.util.Map<java.lang.String,HostAvailability>	getHostAvailabilityMap() Get the host availability map for the failover handler.
java.util.List<HostSpec>	getHostsByPriority(java.util.List<HostSpec> hosts)
ReaderFailoverResult	getReaderConnection(java.util.List<HostSpec> hostList) Called to get any available reader connection.
java.util.List<HostSpec>	getReaderHostsByPriority(java.util.List<HostSpec> hosts)
protected FullServicesContainer	newServicesContainer()
protected void	setTimeoutMs(int timeoutMs) Set process timeout in millis.

Methods inherited from class java.lang.Object

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

Field Detail

FAILED_READER_FAILOVER_RESULT

protected static final ReaderFailoverResult FAILED_READER_FAILOVER_RESULT

DEFAULT_FAILOVER_TIMEOUT

protected static final int DEFAULT_FAILOVER_TIMEOUT

See Also:

Constant Field Values

DEFAULT_READER_CONNECT_TIMEOUT

protected static final int DEFAULT_READER_CONNECT_TIMEOUT

See Also:

Constant Field Values

hostAvailabilityMap

protected final java.util.Map<java.lang.String,HostAvailability> hostAvailabilityMap

servicesContainer

protected final FullServicesContainer servicesContainer

pluginService

protected final PluginService pluginService

props

protected java.util.Properties props

maxFailoverTimeoutMs

protected int maxFailoverTimeoutMs

timeoutMs

protected int timeoutMs

isStrictReaderRequired

protected boolean isStrictReaderRequired

Constructor Detail

ClusterAwareReaderFailoverHandler

public ClusterAwareReaderFailoverHandler(FullServicesContainer servicesContainer,
                                         java.util.Properties props)

ClusterAwareReaderFailoverHandler constructor.

Parameters:

servicesContainer - the service container for the services required by this class.

props - the initial connection properties to copy over to the new reader.

ClusterAwareReaderFailoverHandler

public ClusterAwareReaderFailoverHandler(FullServicesContainer servicesContainer,
                                         java.util.Properties props,
                                         int maxFailoverTimeoutMs,
                                         int timeoutMs,
                                         boolean isStrictReaderRequired)

ClusterAwareReaderFailoverHandler constructor.

Parameters:

servicesContainer - the service container for the services required by this class.

props - the initial connection properties to copy over to the new reader.

maxFailoverTimeoutMs - maximum allowed time for the entire reader failover process.

timeoutMs - maximum allowed time in milliseconds for each reader connection attempt during the reader failover process.

isStrictReaderRequired - when true, it disables adding a writer to a list of nodes to connect

Method Detail

getHostAvailabilityMap

public java.util.Map<java.lang.String,HostAvailability> getHostAvailabilityMap()

Description copied from interface: ReaderFailoverHandler

Get the host availability map for the failover handler. This map will be populated with host availability information during the failover process and can be used to determine which hosts are available.

Specified by:

getHostAvailabilityMap in interface ReaderFailoverHandler

Returns:

the host availability map for the failover handler.

setTimeoutMs

protected void setTimeoutMs(int timeoutMs)

Set process timeout in millis. Entire process of connecting to a reader will be limited by this time duration.

Parameters:

timeoutMs - Process timeout in millis

failover

public ReaderFailoverResult failover(java.util.List<HostSpec> hosts,
                                     HostSpec currentHost)
                              throws java.sql.SQLException

Description copied from interface: ReaderFailoverHandler

Called to start Reader Failover Process. This process tries to connect to any reader. If no reader is available then driver may also try to connect to a writer host, down hosts, and the current reader host.

Specified by:

failover in interface ReaderFailoverHandler

Parameters:

hosts - Cluster current topology.

currentHost - The currently connected host that has failed.

Returns:

ReaderFailoverResult The results of this process.

Throws:

java.sql.SQLException - indicating whether the failover attempt was successful.

failoverInternal

protected ReaderFailoverResult failoverInternal(java.util.List<HostSpec> hosts,
                                                HostSpec currentHost)
                                         throws java.sql.SQLException

Throws:

java.sql.SQLException

getHostsByPriority

public java.util.List<HostSpec> getHostsByPriority(java.util.List<HostSpec> hosts)

getReaderConnection

public ReaderFailoverResult getReaderConnection(java.util.List<HostSpec> hostList)
                                         throws java.sql.SQLException

Called to get any available reader connection. If no reader is available then result of process is unsuccessful. This process will not attempt to connect to the writer.

Specified by:

getReaderConnection in interface ReaderFailoverHandler

Parameters:

hostList - Cluster current topology

Returns:

ReaderFailoverResult The results of this process.

Throws:

java.sql.SQLException - if any error occurred while attempting a reader connection.

getReaderHostsByPriority

public java.util.List<HostSpec> getReaderHostsByPriority(java.util.List<HostSpec> hosts)

newServicesContainer

protected FullServicesContainer newServicesContainer()
                                              throws java.sql.SQLException

Throws:

java.sql.SQLException