AWS DynamoDB Streams

Since Camel 2.17

The DynamoDB Stream component supports receiving messages from Amazon DynamoDB Stream service.

Prerequisites

You must have a valid Amazon Web Services developer account, and be signed up to use Amazon DynamoDB Streams. More information are available at http://aws.amazon.com/dynamodb/[AWS DynamoDB]

URI Format

aws-ddbstream://table-name[?options]

The stream needs to be created prior to it being used.

 You can append query options to the URI in the following format,
?options=value&option2=value&...

URI Options

The AWS DynamoDB Streams component supports 5 options, which are listed below.

Name Description Default Type

configuration (advanced)

The AWS DDB stream default configuration

DdbStreamConfiguration

accessKey (consumer)

Amazon AWS Access Key

String

secretKey (consumer)

Amazon AWS Secret Key

String

region (consumer)

Amazon AWS Region

String

resolveProperty Placeholders (advanced)

Whether the component should resolve property placeholders on itself when starting. Only properties which are of String type can use property placeholders.

true

boolean

The AWS DynamoDB Streams endpoint is configured using URI syntax:

aws-ddbstream:tableName

with the following path and query parameters:

Path Parameters (1 parameters):

Name Description Default Type

tableName

Required Name of the dynamodb table

String

Query Parameters (28 parameters):

Name Description Default Type

amazonDynamoDbStreams Client (consumer)

Amazon DynamoDB client to use for all requests for this endpoint

AmazonDynamoDBStreams

bridgeErrorHandler (consumer)

Allows for bridging the consumer to the Camel routing Error Handler, which mean any exceptions occurred while the consumer is trying to pickup incoming messages, or the likes, will now be processed as a message and handled by the routing Error Handler. By default the consumer will use the org.apache.camel.spi.ExceptionHandler to deal with exceptions, that will be logged at WARN or ERROR level and ignored.

false

boolean

iteratorType (consumer)

Defines where in the DynaboDB stream to start getting records. Note that using TRIM_HORIZON can cause a significant delay before the stream has caught up to real-time. if AT,AFTER_SEQUENCE_NUMBER are used, then a sequenceNumberProvider MUST be supplied.

LATEST

ShardIteratorType

maxResultsPerRequest (consumer)

Maximum number of records that will be fetched in each poll

int

proxyHost (consumer)

To define a proxy host when instantiating the DDBStreams client

String

proxyPort (consumer)

To define a proxy port when instantiating the DDBStreams client

Integer

region (consumer)

The region in which DDBStreams client needs to work

String

sendEmptyMessageWhenIdle (consumer)

If the polling consumer did not poll any files, you can enable this option to send an empty message (no body) instead.

false

boolean

sequenceNumberProvider (consumer)

Provider for the sequence number when using one of the two ShardIteratorType.AT,AFTER_SEQUENCE_NUMBER iterator types. Can be a registry reference or a literal sequence number.

SequenceNumberProvider

exceptionHandler (consumer)

To let the consumer use a custom ExceptionHandler. Notice if the option bridgeErrorHandler is enabled then this option is not in use. By default the consumer will deal with exceptions, that will be logged at WARN or ERROR level and ignored.

ExceptionHandler

exchangePattern (consumer)

Sets the exchange pattern when the consumer creates an exchange.

ExchangePattern

pollStrategy (consumer)

A pluggable org.apache.camel.PollingConsumerPollingStrategy allowing you to provide your custom implementation to control error handling usually occurred during the poll operation before an Exchange have been created and being routed in Camel.

PollingConsumerPoll Strategy

synchronous (advanced)

Sets whether synchronous processing should be strictly used, or Camel is allowed to use asynchronous processing (if supported).

false

boolean

backoffErrorThreshold (scheduler)

The number of subsequent error polls (failed due some error) that should happen before the backoffMultipler should kick-in.

int

backoffIdleThreshold (scheduler)

The number of subsequent idle polls that should happen before the backoffMultipler should kick-in.

int

backoffMultiplier (scheduler)

To let the scheduled polling consumer backoff if there has been a number of subsequent idles/errors in a row. The multiplier is then the number of polls that will be skipped before the next actual attempt is happening again. When this option is in use then backoffIdleThreshold and/or backoffErrorThreshold must also be configured.

int

delay (scheduler)

Milliseconds before the next poll. You can also specify time values using units, such as 60s (60 seconds), 5m30s (5 minutes and 30 seconds), and 1h (1 hour).

500

long

greedy (scheduler)

If greedy is enabled, then the ScheduledPollConsumer will run immediately again, if the previous run polled 1 or more messages.

false

boolean

initialDelay (scheduler)

Milliseconds before the first poll starts. You can also specify time values using units, such as 60s (60 seconds), 5m30s (5 minutes and 30 seconds), and 1h (1 hour).

1000

long

runLoggingLevel (scheduler)

The consumer logs a start/complete log line when it polls. This option allows you to configure the logging level for that.

TRACE

LoggingLevel

scheduledExecutorService (scheduler)

Allows for configuring a custom/shared thread pool to use for the consumer. By default each consumer has its own single threaded thread pool.

ScheduledExecutor Service

scheduler (scheduler)

To use a cron scheduler from either camel-spring or camel-quartz2 component

none

ScheduledPollConsumer Scheduler

schedulerProperties (scheduler)

To configure additional properties when using a custom scheduler or any of the Quartz2, Spring based scheduler.

Map

startScheduler (scheduler)

Whether the scheduler should be auto started.

true

boolean

timeUnit (scheduler)

Time unit for initialDelay and delay options.

MILLISECONDS

TimeUnit

useFixedDelay (scheduler)

Controls if fixed delay or fixed rate is used. See ScheduledExecutorService in JDK for details.

true

boolean

accessKey (security)

Amazon AWS Access Key

String

secretKey (security)

Amazon AWS Secret Key

String

Spring Boot Auto-Configuration

When using Spring Boot make sure to use the following Maven dependency to have support for auto configuration:

<dependency>
  <groupId>org.apache.camel</groupId>
  <artifactId>camel-aws-starter</artifactId>
  <version>x.x.x</version>
  <!-- use the same version as your Camel core version -->
</dependency>

The component supports 15 options, which are listed below.

Name Description Default Type

camel.component.aws-ddbstream.access-key

Amazon AWS Access Key

String

camel.component.aws-ddbstream.configuration.access-key

Amazon AWS Access Key

String

camel.component.aws-ddbstream.configuration.amazon-dynamo-db-streams-client

Amazon DynamoDB client to use for all requests for this endpoint

AmazonDynamoDBStreams

camel.component.aws-ddbstream.configuration.iterator-type

Defines where in the DynaboDB stream to start getting records. Note that using TRIM_HORIZON can cause a significant delay before the stream has caught up to real-time. if AT,AFTER_SEQUENCE_NUMBER are used, then a sequenceNumberProvider MUST be supplied.

ShardIteratorType

camel.component.aws-ddbstream.configuration.max-results-per-request

Maximum number of records that will be fetched in each poll

Integer

camel.component.aws-ddbstream.configuration.proxy-host

To define a proxy host when instantiating the DDBStreams client

String

camel.component.aws-ddbstream.configuration.proxy-port

To define a proxy port when instantiating the DDBStreams client

Integer

camel.component.aws-ddbstream.configuration.region

The region in which DDBStreams client needs to work

String

camel.component.aws-ddbstream.configuration.secret-key

Amazon AWS Secret Key

String

camel.component.aws-ddbstream.configuration.sequence-number-provider

Provider for the sequence number when using one of the two ShardIteratorType.AT,AFTER_SEQUENCE_NUMBER iterator types. Can be a registry reference or a literal sequence number.

SequenceNumberProvider

camel.component.aws-ddbstream.configuration.table-name

Name of the dynamodb table

String

camel.component.aws-ddbstream.enabled

Enable aws-ddbstream component

true

Boolean

camel.component.aws-ddbstream.region

Amazon AWS Region

String

camel.component.aws-ddbstream.resolve-property-placeholders

Whether the component should resolve property placeholders on itself when starting. Only properties which are of String type can use property placeholders.

true

Boolean

camel.component.aws-ddbstream.secret-key

Amazon AWS Secret Key

String

Required DynampDBStream component options

You have to provide the amazonDynamoDbStreamsClient in the Registry with proxies and relevant credentials configured.

Sequence Numbers

You can provide a literal string as the sequence number or provide a bean in the registry. An example of using the bean would be to save your current position in the change feed and restore it on Camel startup.

It is an error to provide a sequence number that is greater than the largest sequence number in the describe-streams result, as this will lead to the AWS call returning an HTTP 400.

Batch Consumer

This component implements the Batch Consumer.

This allows you for instance to know how many messages exists in this batch and for instance let the Aggregator aggregate this number of messages.

Usage

AmazonDynamoDBStreamsClient configuration

You will need to create an instance of AmazonDynamoDBStreamsClient and bind it to the registry

ClientConfiguration clientConfiguration = new ClientConfiguration();
clientConfiguration.setProxyHost("http://myProxyHost");
clientConfiguration.setProxyPort(8080);

Region region = Region.getRegion(Regions.fromName(region));
region.createClient(AmazonDynamoDBStreamsClient.class, null, clientConfiguration);
// the 'null' here is the AWSCredentialsProvider which defaults to an instance of DefaultAWSCredentialsProviderChain

registry.bind("kinesisClient", client);

Providing AWS Credentials

It is recommended that the credentials are obtained by using the DefaultAWSCredentialsProviderChain that is the default when creating a new ClientConfiguration instance, however, a different http://docs.aws.amazon.com/AWSJavaSDK/latest/javadoc/com/amazonaws/auth/AWSCredentialsProvider.html[AWSCredentialsProvider] can be specified when calling createClient(…​).

Coping with Downtime

AWS DynamoDB Streams outage of less than 24 hours

The consumer will resume from the last seen sequence number (as implemented for https://issues.apache.org/jira/browse/CAMEL-9515[CAMEL-9515]), so you should receive a flood of events in quick succession, as long as the outage did not also include DynamoDB itself.

AWS DynamoDB Streams outage of more than 24 hours

Given that AWS only retain 24 hours worth of changes, you will have missed change events no matter what mitigations are in place.

Dependencies

Maven users will need to add the following dependency to their pom.xml.

pom.xml

<dependency>
    <groupId>org.apache.camel</groupId>
    <artifactId>camel-aws</artifactId>
    <version>${camel-version}</version>
</dependency>

where ${camel-version} must be replaced by the actual version of Camel (2.7 or higher).

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