SQSReceiver
SQSReceiver microservice is used to retrieve messages from Amazon Simple Queue Service (SQS).
Configuration and Testing
Component Configurations
The following attributes can be configured in the Interaction Configuration panel as shown below.
Figure 1: Component Configuration Properties
Pre Processing XSL Configuration
Pre Processing XSL configuration can be used to transform request message before processing it. Click the small button against the property to configure the properties.
Refer to the Pre/Post Processing XSL Configuration section under Common Configurations topic for details regarding XSL configuration. The properties comprising this XSL configuration are:
- Provide XSL
- XSLT Engine
- Transformation source data
- Set transformation result as
Post Processing XSL Configuration
Post Processing XSL configuration can be used to transform response message before sending it to the output port.
As mentioned in the above section, refer to the Pre/Post Processing XSL Configuration section under the Common Configurations topic for details regarding XSL configuration.
Process Message Based on Property
The property helps components to skip certain messages from processing.
Refer the Process Message Based On a Property section under the Common Configurations topic.
Validate Input
If this attribute is enabled, the service tries to validate the input received. If disabled, service will not validate the input. For more details, refer Validate Input section section under Interaction Configurations in Common Configurations page.
Performance increases Validate Input option is disabled, but it may cause undesired results in case the input XML is not valid.
Error handling configuration
The remedial actions to be taken when a particular error occurs can be configured using this attribute.
Click the ellipsis button against this property to configure Error Handling properties for different types of Errors. By default, the options Log to error logs, Stop service and Send to error port are enabled.
Refer Error Handling section in Common Configurations for detailed information.
AWS Connection Details
Click the AWS Connection Details ellipsis 
Figure 2: AWS Connection properties
Access key
Specify the Access Key id
Secret key
Specify the Secret Key
Region
The region of AWS Management console.
Queue Name
Name of the queue from which messages are to be obtained.
Delete Messages
Received messages are deleted from queue if enabled.
Attribute Names
Attributes to add to input scheme for easy mapping.
Figure 3: Option to provide attribute names
Amazon SQS can delete your queue without notification if none of the following actions have been performed on it for 30 consecutive days: SendMessage, ReceiveMessage, DeleteMessage, GetQueueAttributes, SetQueueAttributes, AddPermission, and RemovePermission
Threadpool Configuration
This property is used when there is a need to process messages in parallel within the component, still maintaining the sequence from the external perspective.
Click the Threadpool Configuration ellipsis 
Figure 4: Threadpool Configuration properties
Enable Thread Pool
Enable this option to configure the properties that appear as below.
Pool Size
Number of requests to be processed in parallel within the component. Default value is '1'.
Batch Eviction Interval (in ms)
Time in milliseconds after which the threads are evicted in case of inactivity. New threads are created in place of evicted threads when new requests are received. Default value is '1000'.
Functional Demonstration
The following flow demonstrates a flow of SQS Receiver receiving data from the configured Queue
Figure 5: Sample flow demonstrating SQS Receiver functionality
Input Request
The Input message consists of following elements
MaximumNumberOfMessages
The maximum number of messages to return. Amazon SQS never returns more messages than this value but may return fewer .
WaitTimeSeconds
The duration (in seconds) for which the call will wait for a message to arrive in the queue before returning. If a message is available,the call will return sooner than WaitTimeSecond .
VisibilityTimeoutSeconds
The duration (in seconds) that the received messages are hidden from subsequent retrieve requests after being retrieved by a request.
If these properties are not provided, the default properties associated with the configured Queue shall be taken into account.
Figure 6: Sample input request sent using the Feeder microservice
Output Message
The output message consists of following elements
MessageIdentifier
A unique identifier for the message. Message IDs are considered unique across all AWS accounts for an extended period of time
MessageBody
Message's body
ReceiptHandle
An identifier associated with the act of receiving the message. A new receipt handle is returned every time a message is received. When deleting a message, provide the last received receipt handle to delete the message
MD5Body
An MD5 digest of the non-URL-encoded message body string. This can be used to verify that Amazon SQS received the message correctly.
MD5Attributes
An MD5 digest of the non-URL-encoded message attribute string. This can be used to verify that Amazon SQS received the message correctly.
SenderID
Unique ID of the Sender who passed the message to the queue.
ApproximateReceiveCount
Returns the number of times a message has been received from the queue but not deleted.
SentTimestamp
Time Stamp, when the message was received by the queue.
ApproximateFirstReceiveTimestamp
Returns the time the message was first received from the queue (time in milliseconds).
MessageAttribute
- Name: Name of the message obtained from the queue.
- DataType: DataType of the message received.
- Value: Value associated with the data type.
Output Message Structure:
Figure 7: Output message received in the Display microservice