software.amazon.kinesis.worker.metricstats.delegate

Class WorkerMetricStatsDAODelegate<T extends WorkerMetricStats>

java.lang.Object

software.amazon.kinesis.worker.metricstats.delegate.WorkerMetricStatsDAODelegate<T>

Type Parameters:

T - the concrete bean type that maps to the DDB table schema

Direct Known Subclasses:

LeaseTableWorkerMetricStatsDAODelegate, LegacyTableWorkerMetricStatsDAODelegate

public abstract class WorkerMetricStatsDAODelegate<T extends WorkerMetricStats>
extends Object

Data Access Object to abstract accessing WorkerMetricStats from the DDB table it is stored in.

This follows the same delegate pattern as CoordinatorStateDAODelegate. The base class contains all DDB operation implementations. Subclasses provide their specific table name/configuration, bean type T, and override initialize() behavior.

The type parameter T allows subclasses to use the correct bean type for their DDB table schema. The legacy table uses WorkerMetricStats directly (PK attribute: wid), while the lease table uses software.amazon.kinesis.worker.metricstats.LeaseTableWorkerMetricStats (PK attribute: leaseKey).

Field Summary

Fields

Modifier and Type	Field and Description
protected org.slf4j.Logger	log
protected software.amazon.awssdk.enhanced.dynamodb.DynamoDbAsyncTable<T>	table
protected String	tableName

Constructor Summary

Constructors

Constructor and Description
WorkerMetricStatsDAODelegate(software.amazon.awssdk.services.dynamodb.DynamoDbAsyncClient dynamoDbAsyncClient, String tableName, Class<T> beanClass, software.amazon.awssdk.enhanced.dynamodb.TableSchema<T> tableSchema, String paritionKeyAttributeName, Long workerMetricsReporterFrequencyMillis, org.slf4j.Logger logger)

Method Summary

Modifier and Type	Method and Description
boolean	deleteMetrics(WorkerMetricStats workerMetrics) Delete the worker metric stats entry with a conditional check on lastUpdateTime.
abstract List<WorkerMetricStats>	getAllWorkerMetricStats() Retrieve all worker metric stats entries from the backing table
protected software.amazon.awssdk.services.dynamodb.DynamoDbAsyncClient	getDynamoDbAsyncClient()
protected String	getTableName()
abstract void	initialize() Initialize the delegate.
protected abstract T	toEntity(WorkerMetricStats workerMetrics) Convert a base WorkerMetricStats into the concrete bean type T.
void	updateMetrics(WorkerMetricStats workerMetrics) Update (or create) the worker metric stats for a given worker.

Methods inherited from class java.lang.Object

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

Field Detail

log

protected final org.slf4j.Logger log

tableName

protected final String tableName

table

protected final software.amazon.awssdk.enhanced.dynamodb.DynamoDbAsyncTable<T extends WorkerMetricStats> table

Constructor Detail

WorkerMetricStatsDAODelegate

public WorkerMetricStatsDAODelegate(software.amazon.awssdk.services.dynamodb.DynamoDbAsyncClient dynamoDbAsyncClient,
                                    String tableName,
                                    Class<T> beanClass,
                                    software.amazon.awssdk.enhanced.dynamodb.TableSchema<T> tableSchema,
                                    String paritionKeyAttributeName,
                                    Long workerMetricsReporterFrequencyMillis,
                                    org.slf4j.Logger logger)

Parameters:

dynamoDbAsyncClient - the DynamoDB async client

tableName - the name of the DDB table

beanClass - the class of the bean type (needed for UpdateItemEnhancedRequest)

tableSchema - the schema to use for mapping the bean type to/from DDB records

Method Detail

initialize

public abstract void initialize()
                         throws DependencyException

Initialize the delegate. Implementations may check table existence or perform other setup.

Throws:

DependencyException - if initialization fails due to external dependencies

toEntity

protected abstract T toEntity(WorkerMetricStats workerMetrics)

Convert a base WorkerMetricStats into the concrete bean type T. The legacy delegate can simply return the input (since T = WorkerMetricStats), while the lease table delegate converts to LeaseTableWorkerMetricStats.

getDynamoDbAsyncClient

protected software.amazon.awssdk.services.dynamodb.DynamoDbAsyncClient getDynamoDbAsyncClient()

getTableName

protected String getTableName()

getAllWorkerMetricStats

public abstract List<WorkerMetricStats> getAllWorkerMetricStats()
                                                         throws DependencyException,
                                                                InvalidStateException,
                                                                ProvisionedThroughputException

Retrieve all worker metric stats entries from the backing table

Returns:

list of all WorkerMetricStats entries

Throws:

DependencyException - if DynamoDB operation fails unexpectedly

InvalidStateException - if the backing table does not exist

ProvisionedThroughputException - if DynamoDB lacks capacity

updateMetrics

public void updateMetrics(WorkerMetricStats workerMetrics)
                   throws DependencyException,
                          InvalidStateException,
                          ProvisionedThroughputException

Update (or create) the worker metric stats for a given worker. Performs an upsert, ignoring null attributes.

Parameters:

workerMetrics - the worker metrics to persist

Throws:

DependencyException - if DynamoDB operation fails unexpectedly

InvalidStateException - if the backing table does not exist

ProvisionedThroughputException - if DynamoDB lacks capacity

deleteMetrics

public boolean deleteMetrics(WorkerMetricStats workerMetrics)
                      throws DependencyException,
                             InvalidStateException,
                             ProvisionedThroughputException

Delete the worker metric stats entry with a conditional check on lastUpdateTime. If the worker has come alive and updated the lastUpdateTime since the provided entry was read, the deletion will fail gracefully.

Parameters:

workerMetrics - the entry to delete (workerId and lastUpdateTime required)

Returns:

true if deleted, false if the conditional check failed

Throws:

DependencyException - if DynamoDB operation fails unexpectedly

InvalidStateException - if the backing table does not exist

ProvisionedThroughputException - if DynamoDB lacks capacity