software.amazon.kinesis.leases

Interface LeaseCoordinator

All Known Implementing Classes:

DynamoDBLeaseCoordinator

public interface LeaseCoordinator

Method Summary

Modifier and Type	Method and Description
default List<Lease>	allLeases() Default implementation returns an empty list and concrete implementation is expected to return all leases for the application that are in the lease table.
void	dropLease(Lease lease) Requests that renewals for the given lease are stopped.
Collection<Lease>	getAssignments()
List<ShardInfo>	getCurrentAssignments()
Lease	getCurrentlyHeldLease(String leaseKey)
void	initialize() Initialize the lease coordinator (create the lease table if needed).
DynamoDBLeaseCoordinator	initialLeaseTableReadCapacity(long readCapacity)
DynamoDBLeaseCoordinator	initialLeaseTableWriteCapacity(long writeCapacity)
boolean	isRunning()
LeaseRefresher	leaseRefresher()
void	runLeaseRenewer() Runs a single iteration of the lease renewer - used by integration tests.
void	runLeaseTaker() Runs a single iteration of the lease taker - used by integration tests.
void	start() Start background LeaseHolder and LeaseTaker threads.
void	stop() Stops background threads and waits for specific amount of time for all background tasks to complete.
void	stopLeaseTaker() Requests the cancellation of the lease taker.
boolean	updateLease(Lease lease, UUID concurrencyToken, String operation, String shardId) Updates application-specific lease values in DynamoDB.
String	workerIdentifier()

Method Detail

initialize

void initialize()
         throws ProvisionedThroughputException,
                DependencyException,
                IllegalStateException

Initialize the lease coordinator (create the lease table if needed).

Throws:

DependencyException

ProvisionedThroughputException

IllegalStateException

start

void start()
    throws DependencyException,
           InvalidStateException,
           ProvisionedThroughputException

Start background LeaseHolder and LeaseTaker threads.

Throws:

ProvisionedThroughputException - If we can't talk to DynamoDB due to insufficient capacity.

InvalidStateException - If the lease table doesn't exist

DependencyException - If we encountered exception taking to DynamoDB

runLeaseTaker

void runLeaseTaker()
            throws DependencyException,
                   InvalidStateException

Runs a single iteration of the lease taker - used by integration tests.

Throws:

InvalidStateException

DependencyException

runLeaseRenewer

void runLeaseRenewer()
              throws DependencyException,
                     InvalidStateException

Runs a single iteration of the lease renewer - used by integration tests.

Throws:

InvalidStateException

DependencyException

isRunning

boolean isRunning()

Returns:

true if this LeaseCoordinator is running

workerIdentifier

String workerIdentifier()

Returns:

workerIdentifier

leaseRefresher

LeaseRefresher leaseRefresher()

Returns:

LeaseRefresher

getAssignments

Collection<Lease> getAssignments()

Returns:

currently held leases

getCurrentlyHeldLease

Lease getCurrentlyHeldLease(String leaseKey)

Parameters:

leaseKey - lease key to fetch currently held lease for

Returns:

deep copy of currently held Lease for given key, or null if we don't hold the lease for that key

updateLease

boolean updateLease(Lease lease,
                    UUID concurrencyToken,
                    String operation,
                    String shardId)
             throws DependencyException,
                    InvalidStateException,
                    ProvisionedThroughputException

Updates application-specific lease values in DynamoDB.

Parameters:

lease - lease object containing updated values

concurrencyToken - obtained by calling Lease.concurrencyToken for a currently held lease

Returns:

true if update succeeded, false otherwise

Throws:

InvalidStateException - if lease table does not exist

ProvisionedThroughputException - if DynamoDB update fails due to lack of capacity

DependencyException - if DynamoDB update fails in an unexpected way

stopLeaseTaker

void stopLeaseTaker()

Requests the cancellation of the lease taker.

dropLease

void dropLease(Lease lease)

Requests that renewals for the given lease are stopped.

Parameters:

lease - the lease to stop renewing.

stop

void stop()

Stops background threads and waits for specific amount of time for all background tasks to complete. If tasks are not completed after this time, method will shutdown thread pool forcefully and return.

getCurrentAssignments

List<ShardInfo> getCurrentAssignments()

Returns:

Current shard/lease assignments

allLeases

default List<Lease> allLeases()

Default implementation returns an empty list and concrete implementation is expected to return all leases for the application that are in the lease table. This enables application managing Kcl Scheduler to take care of horizontal scaling for example.

Returns:

all leases for the application that are in the lease table

initialLeaseTableWriteCapacity

DynamoDBLeaseCoordinator initialLeaseTableWriteCapacity(long writeCapacity)

Parameters:

writeCapacity - The DynamoDB table used for tracking leases will be provisioned with the specified initial write capacity

Returns:

LeaseCoordinator

initialLeaseTableReadCapacity

DynamoDBLeaseCoordinator initialLeaseTableReadCapacity(long readCapacity)

Parameters:

readCapacity - The DynamoDB table used for tracking leases will be provisioned with the specified initial read capacity

Returns:

LeaseCoordinator