AWS Simple Notification System (SNS)

Since Camel 3.1

Only producer is supported

The AWS2 SNS component allows messages to be sent to an Amazon Simple Notification Topic. The implementation of the Amazon API is provided by the AWS SDK.

Prerequisites

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

URI Format

aws2-sns://topicNameOrArn[?options]

The topic will be created if they don’t already exist.

You can append query options to the URI in the following format:

?options=value&option2=value&…​

URI Options

Configuring Options

Camel components are configured on two separate levels:

  • component level

  • endpoint level

Configuring Component Options

The component level is the highest level which holds general and common configurations that are inherited by the endpoints. For example a component may have security settings, credentials for authentication, urls for network connection and so forth.

Some components only have a few options, and others may have many. Because components typically have pre configured defaults that are commonly used, then you may often only need to configure a few options on a component; or none at all.

Configuring components can be done with the Component DSL, in a configuration file (application.properties|yaml), or directly with Java code.

Configuring Endpoint Options

Where you find yourself configuring the most is on endpoints, as endpoints often have many options, which allows you to configure what you need the endpoint to do. The options are also categorized into whether the endpoint is used as consumer (from) or as a producer (to), or used for both.

Configuring endpoints is most often done directly in the endpoint URI as path and query parameters. You can also use the Endpoint DSL and DataFormat DSL as a type safe way of configuring endpoints and data formats in Java.

A good practice when configuring options is to use Property Placeholders, which allows to not hardcode urls, port numbers, sensitive information, and other settings. In other words placeholders allows to externalize the configuration from your code, and gives more flexibility and reuse.

The following two sections lists all the options, firstly for the component followed by the endpoint.

Component Options

The AWS Simple Notification System (SNS) component supports 30 options, which are listed below.

Name Description Default Type

autoCreateTopic (producer)

Setting the auto-creation of the topic.

false

boolean

configuration (producer)

Component configuration.

Sns2Configuration

kmsMasterKeyId (producer)

The ID of an AWS-managed customer master key (CMK) for Amazon SNS or a custom CMK.

String

lazyStartProducer (producer)

Whether the producer should be started lazy (on the first message). By starting lazy you can use this to allow CamelContext and routes to startup in situations where a producer may otherwise fail during starting and cause the route to fail being started. By deferring this startup to be lazy then the startup failure can be handled during routing messages via Camel’s routing error handlers. Beware that when the first message is processed then creating and starting the producer may take a little time and prolong the total processing time of the processing.

false

boolean

messageDeduplicationIdStrategy (producer)

Only for FIFO Topic. Strategy for setting the messageDeduplicationId on the message. It can be one of the following options: useExchangeId, useContentBasedDeduplication. For the useContentBasedDeduplication option, no messageDeduplicationId will be set on the message.

Enum values:

  • useExchangeId

  • useContentBasedDeduplication

useExchangeId

String

messageGroupIdStrategy (producer)

Only for FIFO Topic. Strategy for setting the messageGroupId on the message. It can be one of the following options: useConstant, useExchangeId, usePropertyValue. For the usePropertyValue option, the value of property CamelAwsMessageGroupId will be used.

Enum values:

  • useConstant

  • useExchangeId

  • usePropertyValue

String

messageStructure (producer)

The message structure to use such as json.

String

overrideEndpoint (producer)

Set the need for overriding the endpoint. This option needs to be used in combination with the uriEndpointOverride option.

false

boolean

policy (producer)

The policy for this topic. Is loaded by default from classpath, but you can prefix with classpath:, file:, or http: to load the resource from different systems.

String

queueArn (producer)

The ARN endpoint to subscribe to.

String

region (producer)

The region in which the SNS client needs to work. When using this parameter, the configuration will expect the lowercase name of the region (for example, ap-east-1) You’ll need to use the name Region.EU_WEST_1.id().

Enum values:

  • ap-south-2

  • ap-south-1

  • eu-south-1

  • eu-south-2

  • us-gov-east-1

  • me-central-1

  • il-central-1

  • ca-central-1

  • eu-central-1

  • us-iso-west-1

  • eu-central-2

  • us-west-1

  • us-west-2

  • af-south-1

  • eu-north-1

  • eu-west-3

  • eu-west-2

  • eu-west-1

  • ap-northeast-3

  • ap-northeast-2

  • ap-northeast-1

  • me-south-1

  • sa-east-1

  • ap-east-1

  • cn-north-1

  • us-gov-west-1

  • ap-southeast-1

  • ap-southeast-2

  • us-iso-east-1

  • ap-southeast-3

  • ap-southeast-4

  • us-east-1

  • us-east-2

  • cn-northwest-1

  • us-isob-east-1

  • aws-global

  • aws-cn-global

  • aws-us-gov-global

  • aws-iso-global

  • aws-iso-b-global

String

serverSideEncryptionEnabled (producer)

Define if Server Side Encryption is enabled or not on the topic.

false

boolean

subject (producer)

The subject which is used if the message header 'CamelAwsSnsSubject' is not present.

String

subscribeSNStoSQS (producer)

Define if the subscription between SNS Topic and SQS must be done or not.

false

boolean

uriEndpointOverride (producer)

Set the overriding uri endpoint. This option needs to be used in combination with overrideEndpoint option.

String

amazonSNSClient (advanced)

Autowired To use the AmazonSNS as the client.

SnsClient

autowiredEnabled (advanced)

Whether autowiring is enabled. This is used for automatic autowiring options (the option must be marked as autowired) by looking up in the registry to find if there is a single instance of matching type, which then gets configured on the component. This can be used for automatic configuring JDBC data sources, JMS connection factories, AWS Clients, etc.

true

boolean

healthCheckConsumerEnabled (health)

Used for enabling or disabling all consumer based health checks from this component.

true

boolean

healthCheckProducerEnabled (health)

Used for enabling or disabling all producer based health checks from this component. Notice: Camel has by default disabled all producer based health-checks. You can turn on producer checks globally by setting camel.health.producersEnabled=true.

true

boolean

proxyHost (proxy)

To define a proxy host when instantiating the SNS client.

String

proxyPort (proxy)

To define a proxy port when instantiating the SNS client.

Integer

proxyProtocol (proxy)

To define a proxy protocol when instantiating the SNS client.

Enum values:

  • HTTP

  • HTTPS

HTTPS

Protocol

accessKey (security)

Amazon AWS Access Key.

String

profileCredentialsName (security)

If using a profile credentials provider, this parameter will set the profile name.

String

secretKey (security)

Amazon AWS Secret Key.

String

sessionToken (security)

Amazon AWS Session Token used when the user needs to assume an IAM role.

String

trustAllCertificates (security)

If we want to trust all certificates in case of overriding the endpoint.

false

boolean

useDefaultCredentialsProvider (security)

Set whether the SNS client should expect to load credentials on an AWS infra instance or to expect static credentials to be passed in.

false

boolean

useProfileCredentialsProvider (security)

Set whether the SNS client should expect to load credentials through a profile credentials provider.

false

boolean

useSessionCredentials (security)

Set whether the SNS client should expect to use Session Credentials. This is useful in a situation in which the user needs to assume an IAM role for doing operations in SNS.

false

boolean

Endpoint Options

The AWS Simple Notification System (SNS) endpoint is configured using URI syntax:

aws2-sns:topicNameOrArn

with the following path and query parameters:

Path Parameters (1 parameters)

Name Description Default Type

topicNameOrArn (producer)

Required Topic name or ARN.

String

Query Parameters (27 parameters)

Name Description Default Type

autoCreateTopic (producer)

Setting the auto-creation of the topic.

false

boolean

headerFilterStrategy (producer)

To use a custom HeaderFilterStrategy to map headers to/from Camel.

HeaderFilterStrategy

kmsMasterKeyId (producer)

The ID of an AWS-managed customer master key (CMK) for Amazon SNS or a custom CMK.

String

messageDeduplicationIdStrategy (producer)

Only for FIFO Topic. Strategy for setting the messageDeduplicationId on the message. It can be one of the following options: useExchangeId, useContentBasedDeduplication. For the useContentBasedDeduplication option, no messageDeduplicationId will be set on the message.

Enum values:

  • useExchangeId

  • useContentBasedDeduplication

useExchangeId

String

messageGroupIdStrategy (producer)

Only for FIFO Topic. Strategy for setting the messageGroupId on the message. It can be one of the following options: useConstant, useExchangeId, usePropertyValue. For the usePropertyValue option, the value of property CamelAwsMessageGroupId will be used.

Enum values:

  • useConstant

  • useExchangeId

  • usePropertyValue

String

messageStructure (producer)

The message structure to use such as json.

String

overrideEndpoint (producer)

Set the need for overriding the endpoint. This option needs to be used in combination with the uriEndpointOverride option.

false

boolean

policy (producer)

The policy for this topic. Is loaded by default from classpath, but you can prefix with classpath:, file:, or http: to load the resource from different systems.

String

queueArn (producer)

The ARN endpoint to subscribe to.

String

region (producer)

The region in which the SNS client needs to work. When using this parameter, the configuration will expect the lowercase name of the region (for example, ap-east-1) You’ll need to use the name Region.EU_WEST_1.id().

Enum values:

  • ap-south-2

  • ap-south-1

  • eu-south-1

  • eu-south-2

  • us-gov-east-1

  • me-central-1

  • il-central-1

  • ca-central-1

  • eu-central-1

  • us-iso-west-1

  • eu-central-2

  • us-west-1

  • us-west-2

  • af-south-1

  • eu-north-1

  • eu-west-3

  • eu-west-2

  • eu-west-1

  • ap-northeast-3

  • ap-northeast-2

  • ap-northeast-1

  • me-south-1

  • sa-east-1

  • ap-east-1

  • cn-north-1

  • us-gov-west-1

  • ap-southeast-1

  • ap-southeast-2

  • us-iso-east-1

  • ap-southeast-3

  • ap-southeast-4

  • us-east-1

  • us-east-2

  • cn-northwest-1

  • us-isob-east-1

  • aws-global

  • aws-cn-global

  • aws-us-gov-global

  • aws-iso-global

  • aws-iso-b-global

String

serverSideEncryptionEnabled (producer)

Define if Server Side Encryption is enabled or not on the topic.

false

boolean

subject (producer)

The subject which is used if the message header 'CamelAwsSnsSubject' is not present.

String

subscribeSNStoSQS (producer)

Define if the subscription between SNS Topic and SQS must be done or not.

false

boolean

uriEndpointOverride (producer)

Set the overriding uri endpoint. This option needs to be used in combination with overrideEndpoint option.

String

lazyStartProducer (producer (advanced))

Whether the producer should be started lazy (on the first message). By starting lazy you can use this to allow CamelContext and routes to startup in situations where a producer may otherwise fail during starting and cause the route to fail being started. By deferring this startup to be lazy then the startup failure can be handled during routing messages via Camel’s routing error handlers. Beware that when the first message is processed then creating and starting the producer may take a little time and prolong the total processing time of the processing.

false

boolean

amazonSNSClient (advanced)

Autowired To use the AmazonSNS as the client.

SnsClient

proxyHost (proxy)

To define a proxy host when instantiating the SNS client.

String

proxyPort (proxy)

To define a proxy port when instantiating the SNS client.

Integer

proxyProtocol (proxy)

To define a proxy protocol when instantiating the SNS client.

Enum values:

  • HTTP

  • HTTPS

HTTPS

Protocol

accessKey (security)

Amazon AWS Access Key.

String

profileCredentialsName (security)

If using a profile credentials provider, this parameter will set the profile name.

String

secretKey (security)

Amazon AWS Secret Key.

String

sessionToken (security)

Amazon AWS Session Token used when the user needs to assume an IAM role.

String

trustAllCertificates (security)

If we want to trust all certificates in case of overriding the endpoint.

false

boolean

useDefaultCredentialsProvider (security)

Set whether the SNS client should expect to load credentials on an AWS infra instance or to expect static credentials to be passed in.

false

boolean

useProfileCredentialsProvider (security)

Set whether the SNS client should expect to load credentials through a profile credentials provider.

false

boolean

useSessionCredentials (security)

Set whether the SNS client should expect to use Session Credentials. This is useful in a situation in which the user needs to assume an IAM role for doing operations in SNS.

false

boolean

Required SNS component options

You have to provide the amazonSNSClient in the Registry or your accessKey and secretKey to access the Amazon’s SNS.

Usage

Static credentials, Default Credential Provider and Profile Credentials Provider

You have the possibility of avoiding the usage of explicit static credentials by specifying the useDefaultCredentialsProvider option and set it to true.

The order of evaluation for Default Credentials Provider is the following:

  • Java system properties - aws.accessKeyId and aws.secretKey.

  • Environment variables - AWS_ACCESS_KEY_ID and AWS_SECRET_ACCESS_KEY.

  • Web Identity Token from AWS STS.

  • The shared credentials and config files.

  • Amazon ECS container credentials - loaded from the Amazon ECS if the environment variable AWS_CONTAINER_CREDENTIALS_RELATIVE_URI is set.

  • Amazon EC2 Instance profile credentials.

You have also the possibility of using Profile Credentials Provider, by specifying the useProfileCredentialsProvider option to true and profileCredentialsName to the profile name.

Only one of static, default and profile credentials could be used at the same time.

For more information about this you can look at AWS credentials documentation

Message Headers

The AWS Simple Notification System (SNS) component supports 3 message header(s), which is/are listed below:

Name Description Default Type

CamelAwsSnsMessageId (producer)

Constant: MESSAGE_ID

The Amazon SNS message ID.

String

CamelAwsSnsSubject (producer)

Constant: SUBJECT

The Amazon SNS message subject. If not set, the subject from the SnsConfiguration is used.

String

CamelAwsSnsMessageStructure (producer)

Constant: MESSAGE_STRUCTURE

The message structure to use such as json.

String

Advanced AmazonSNS configuration

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

from("direct:start")
.to("aws2-sns://MyTopic?amazonSNSClient=#client");

The #client refers to a AmazonSNS in the Registry.

Create a subscription between an AWS SNS Topic and an AWS SQS Queue

You can create a subscription of an SQS Queue to an SNS Topic in this way:

from("direct:start")
.to("aws2-sns://test-camel-sns1?amazonSNSClient=#amazonSNSClient&subscribeSNStoSQS=true&queueArn=arn:aws:sqs:eu-central-1:123456789012:test_camel");

The #amazonSNSClient refers to a SnsClient in the Registry. By specifying subscribeSNStoSQS to true and a queueArn of an existing SQS Queue, you’ll be able to subscribe your SQS Queue to your SNS Topic.

At this point, you can consume messages coming from SNS Topic through your SQS Queue

from("aws2-sqs://test-camel?amazonSQSClient=#amazonSQSClient&delay=50&maxMessagesPerPoll=5")
    .to(...);

Topic Autocreation

With the option autoCreateTopic users are able to avoid the autocreation of an SNS Topic in case it doesn’t exist. The default for this option is false. If set to false, any operation on a non-existent topic in AWS won’t be successful and an error will be returned.

SNS FIFO

SNS FIFO are supported. While creating the SQS queue, you will subscribe to the SNS topic there is an important point to remember, you’ll need to make possible for the SNS Topic to send the message to the SQS Queue.

This is clear with an example.

Suppose you created an SNS FIFO Topic called Order.fifo and an SQS Queue called QueueSub.fifo.

In the access Policy of the QueueSub.fifo you should submit something like this

{
  "Version": "2008-10-17",
  "Id": "__default_policy_ID",
  "Statement": [
    {
      "Sid": "__owner_statement",
      "Effect": "Allow",
      "Principal": {
        "AWS": "arn:aws:iam::780560123482:root"
      },
      "Action": "SQS:*",
      "Resource": "arn:aws:sqs:eu-west-1:780560123482:QueueSub.fifo"
    },
    {
      "Effect": "Allow",
      "Principal": {
        "Service": "sns.amazonaws.com"
      },
      "Action": "SQS:SendMessage",
      "Resource": "arn:aws:sqs:eu-west-1:780560123482:QueueSub.fifo",
      "Condition": {
        "ArnLike": {
          "aws:SourceArn": "arn:aws:sns:eu-west-1:780410022472:Order.fifo"
        }
      }
    }
  ]
}

This is a critical step to make the subscription work correctly.

SNS Fifo Topic Message group ID Strategy and message Deduplication ID Strategy

When sending something to the FIFO topic, you’ll need to always set up a message group ID strategy.

If the content-based message deduplication has been enabled on the SNS Fifo topic, where won’t be the need of setting a message deduplication id strategy, otherwise you’ll have to set it.

Examples

Producer Examples

Sending to a topic

from("direct:start")
  .to("aws2-sns://camel-topic?subject=The+subject+message&autoCreateTopic=true");

Dependencies

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

pom.xml

<dependency>
    <groupId>org.apache.camel</groupId>
    <artifactId>camel-aws2-sns</artifactId>
    <version>${camel-version}</version>
</dependency>

where ${camel-version} must be replaced by the actual version of Camel.