Chapter 34. AWS Simple Workflow Component

Available as of Camel version 2.13

The Simple Workflow component supports managing workflows from Amazon’s Simple Workflow service.

Prerequisites

You must have a valid Amazon Web Services developer account, and be signed up to use Amazon Simple Workflow. More information are available at Amazon Simple Workflow.

34.1. URI Format

aws-swf://<workflow|activity>[?options]

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

34.2. URI Options

The AWS Simple Workflow component supports 5 options which are listed below.

NameDescriptionDefaultType

configuration (advanced)

The AWS SWF default configuration

 

SWFConfiguration

accessKey (common)

Amazon AWS Access Key.

 

String

secretKey (common)

Amazon AWS Secret Key.

 

String

region (common)

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 Simple Workflow endpoint is configured using URI syntax:

aws-swf:type

with the following path and query parameters:

34.2.1. Path Parameters (1 parameters):

NameDescriptionDefaultType

type

Required Activity or workflow

 

String

34.2.2. Query Parameters (30 parameters):

NameDescriptionDefaultType

amazonSWClient (common)

To use the given AmazonSimpleWorkflowClient as client

 

AmazonSimpleWorkflow Client

dataConverter (common)

An instance of com.amazonaws.services.simpleworkflow.flow.DataConverter to use for serializing/deserializing the data.

 

DataConverter

domainName (common)

The workflow domain to use.

 

String

eventName (common)

The workflow or activity event name to use.

 

String

region (common)

Amazon AWS Region.

 

String

version (common)

The workflow or activity event version to use.

 

String

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

exceptionHandler (consumer)

To let the consumer use a custom ExceptionHandler. Notice if the option bridgeErrorHandler is enabled then this options 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

clientConfiguration Parameters (advanced)

To configure the ClientConfiguration using the key/values from the Map.

 

Map

startWorkflowOptions Parameters (advanced)

To configure the StartWorkflowOptions using the key/values from the Map.

 

Map

sWClientParameters (advanced)

To configure the AmazonSimpleWorkflowClient using the key/values from the Map.

 

Map

synchronous (advanced)

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

false

boolean

activityList (activity)

The list name to consume activities from.

 

String

activitySchedulingOptions (activity)

Activity scheduling options

 

ActivityScheduling Options

activityThreadPoolSize (activity)

Maximum number of threads in work pool for activity.

100

int

activityTypeExecution Options (activity)

Activity execution options

 

ActivityTypeExecution Options

activityTypeRegistration Options (activity)

Activity registration options

 

ActivityType RegistrationOptions

childPolicy (workflow)

The policy to use on child workflows when terminating a workflow.

 

String

executionStartToClose Timeout (workflow)

Set the execution start to close timeout.

3600

String

operation (workflow)

Workflow operation

START

String

signalName (workflow)

The name of the signal to send to the workflow.

 

String

stateResultType (workflow)

The type of the result when a workflow state is queried.

 

String

taskStartToCloseTimeout (workflow)

Set the task start to close timeout.

600

String

terminationDetails (workflow)

Details for terminating a workflow.

 

String

terminationReason (workflow)

The reason for terminating a workflow.

 

String

workflowList (workflow)

The list name to consume workflows from.

 

String

workflowTypeRegistration Options (workflow)

Workflow registration options

 

WorkflowType RegistrationOptions

accessKey (security)

Amazon AWS Access Key.

 

String

secretKey (security)

Amazon AWS Secret Key.

 

String

Required SWF component options

You have to provide the amazonSWClient in the Registry or your accessKey and secretKey to access the Amazon’s Simple Workflow Service.

34.3. Usage

34.3.1. Message headers evaluated by the SWF Workflow Producer

A workflow producer allows interacting with a workflow. It can start a new workflow execution, query its state, send signals to a running workflow, or terminate and cancel it.

HeaderTypeDescription

CamelSWFOperation

String

The operation to perform on the workflow. Supported operations are:
SIGNAL, CANCEL, TERMINATE, GET_STATE, START, DESCRIBE, GET_HISTORY.

CamelSWFWorkflowId

String

A workflow ID to use.

CamelAwsDdbKeyCamelSWFRunId

String

A worfklow run ID to use.

CamelSWFStateResultType

String

The type of the result when a workflow state is queried.

CamelSWFEventName

String

The workflow or activity event name to use.

CamelSWFVersion

String

The workflow or activity event version to use.

CamelSWFReason

String

The reason for terminating a workflow.

CamelSWFDetails

String

Details for terminating a workflow.

CamelSWFChildPolicy

String

The policy to use on child workflows when terminating a workflow.

34.3.2. Message headers set by the SWF Workflow Producer

HeaderTypeDescription

CamelSWFWorkflowId

String

The worfklow ID used or newly generated.

CamelAwsDdbKeyCamelSWFRunId

String

The worfklow run ID used or generated.

34.3.3. Message headers set by the SWF Workflow Consumer

A workflow consumer represents the workflow logic. When it is started, it will start polling workflow decision tasks and process them. In addition to processing decision tasks, a workflow consumer route, will also receive signals (send from a workflow producer) or state queries. The primary purpose of a workflow consumer is to schedule activity tasks for execution using activity producers. Actually activity tasks can be scheduled only from a thread started by a workflow consumer.

HeaderTypeDescription

CamelSWFAction

String

Indicates what type is the current event: CamelSWFActionExecute, CamelSWFSignalReceivedAction or CamelSWFGetStateAction.

CamelSWFWorkflowReplaying

boolean

Indicates whether the current decision task is a replay or not.

CamelSWFWorkflowStartTime

long

The time of the start event for this decision task.

34.3.4. Message headers set by the SWF Activity Producer

An activity producer allows scheduling activity tasks. An activity producer can be used only from a thread started by a workflow consumer ie, it can process synchronous exchanges started by a workflow consumer.

HeaderTypeDescription

CamelSWFEventName

String

The activity name to schedule.

CamelSWFVersion

String

The activity version to schedule.

34.3.5. Message headers set by the SWF Activity Consumer

HeaderTypeDescription

CamelSWFTaskToken

String

The task token that is required to report task completion for manually completed tasks.

34.3.6. Advanced amazonSWClient configuration

If you need more control over the AmazonSimpleWorkflowClient instance configuration you can create your own instance and refer to it from the URI:

The #client refers to a AmazonSimpleWorkflowClient in the Registry.

For example if your Camel Application is running behind a firewall:

AWSCredentials awsCredentials = new BasicAWSCredentials("myAccessKey", "mySecretKey");
ClientConfiguration clientConfiguration = new ClientConfiguration();
clientConfiguration.setProxyHost("http://myProxyHost");
clientConfiguration.setProxyPort(8080);

AmazonSimpleWorkflowClient client = new AmazonSimpleWorkflowClient(awsCredentials, clientConfiguration);

registry.bind("client", client);

34.4. 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 (2.13 or higher).

34.5. See Also

  • Configuring Camel
  • Component
  • Endpoint
  • Getting Started

AWS Component