Chapter 40. Azure Storage Queue Service Component

Available as of Camel version 2.19

The Azure Queue component supports storing and retrieving the messages to/from Azure Storage Queue service.

Prerequisites

You must have a valid Windows Azure Storage account. More information is available at Azure Documentation Portal.

40.1. URI Format

azure-queue://accountName/queueName[?options]

The queue will be created if it does not already exist.
You can append query options to the URI in the following format: ?options=value&option2=value&…​

For example, to get a message content from the queue messageQueue in the camelazure storage account, use the following snippet: 

from("azure-queue:camelazure/messageQueue").
to("file://queuedirectory");

40.2. URI Options

The Azure Storage Queue Service component has no options.

The Azure Storage Queue Service endpoint is configured using URI syntax: 

azure-queue:containerAndQueueUri

with the following path and query parameters:

40.2.1. Path Parameters (1 parameter)

NameDescriptionDefaultType

containerAndQueueUri

Required: Container Queue compact URI.

 

String

40.2.2. Query Parameters (27 parameters)

NameDescriptionDefaultType

azureQueueClient (common)

The queue service client.

 

CloudQueue

credentials (common)

Set the storage credentials, required in most cases.

 

StorageCredentials

credentialsAccountKey (common)

Set the storage account key used during authentication phase.

 

String

credentialsAccountName (common)

Set the storage account name used during authentication phase.

 

String

bridgeErrorHandler (consumer)

Allows for bridging the consumer to the Camel routing Error Handler. This means any exceptions that occurred (for example, while the consumer was trying to pick up incoming messages) 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

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

exceptionHandler (consumer)

To let the consumer use a custom ExceptionHandler. Note that if the option bridgeErrorHandler is enabled, 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 occurring during the poll operation before an Exchange has been created which will be routed in Camel.

 

PollingConsumerPoll Strategy

messageTimeToLive (producer)

Message Time To Live in seconds.

 

int

messageVisibilityDelay (producer)

Message Visibility Delay in seconds.

 

int

operation (producer)

Queue service operation hint to the producer.

listQueues

QueueServiceOperations

queuePrefix (producer)

Set a prefix which can be used for listing the queues.

 

String

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 to 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 happens 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

Required Azure Storage Queue Service component options

You must provide the containerAndQueue URI and the credentials.

40.3. Usage

40.3.1. Azure Queue Service operations

OperationDescription

listQueues

List the queues.

createQueue

Create the queue.

deleteQueue

Delete the queue.

addMessage

Add a message to the queue.

retrieveMessage

Retrieve a message from the queue.

peekMessage

View the message inside the queue, for example, to determine whether the message arrived at the correct queue.

updateMessage

Update the message in the queue.

deleteMessage

Delete the message in the queue.

40.3.2. Azure Queue Client configuration

If your Camel Application is running behind a firewall or if you need to have more control over the Azure Queue Client configuration, you can create your own instance: 

StorageCredentials credentials = new StorageCredentialsAccountAndKey("camelazure", "thekey");

CloudQueue client = new CloudQueue("camelazure", credentials);

registry.bind("azureQueueClient", client);

and refer to it in your Camel azure-queue component configuration: 

from("azure-queue:camelazure/messageQueue?azureQueueClient=#client")
.to("mock:result");

40.4. Dependencies

Maven users must add the following dependency to their pom.xml.

pom.xml 

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

where ${camel-version} must be replaced by the actual version of Camel (2.19.0 or higher).

40.5. See Also

  • Configuring Camel
  • Component
  • Endpoint
  • Getting Started
  • Azure Component