Configuring Connection Details

Solace PubSub+ Connection Details

The Spring Cloud Stream Binder for PubSub+ uses Spring Boot Auto-Configuration for the Solace Java API to configure its session. In the application.yml, this typically is configured as follows:

solace:
  java:
    host: tcp://localhost:55555
    msg-vpn: default
    client-username: default
    client-password: default	

For more information and options to configure the PubSub+ session, see Spring Boot Auto-Configuration for the Solace Java API

Preventing Message Loss when Publishing to Topic-to-Queue Mappings

If the connector is publishing to a topic that is subscribed to by a queue, messages may be lost if they are rejected. For example, if the queue ingress is shutdown.

To prevent message loss, configure the reject-msg-to-sender-on-discard with the including-when-shutdown flag.

Amazon SNS Connection Details

We presume that you are familiar with the Spring Cloud AWS Credentials, however he steps that follow help you to connect to AWS services without in-depth knowledge. The connector can find these credentials automatically, or you can specify them manually.

Automatic Credential Discovery

By default, the connector auto-configures a DefaultCredentialsProvider which looks for AWS credentials in the following order:

1. Java System Properties—aws.accessKeyId and aws.secretAccessKey

2. Environment Variables—AWS_ACCESS_KEY_ID and AWS_SECRET_ACCESS_KEY

3. Web Identity Tokens—The credentials from system properties or environment variables

4. Credential Profiles Files—The default location is at ~/.aws/credentials, which is shared by all AWS SDKs and the AWS CLI.

5. Amazon EC2 Container Services—The credentials delivered through the Amazon EC2 container service if the AWS_CONTAINER_CREDENTIALS_RELATIVE_URI environment variable is set and and security manager has permission to access the variable.

6. Instance Profile Credentials—These credentials are delivered through the Amazon EC2 metadata service.

Manual Credential Discovery

Alternatively, you can instead provide the necessary credentials through the application. You can use the Spring Cloud AWS authentication libraries are configurable using several properties as described in the Configuring Spring Cloud AWS credentials. You can set the cloud.aws.credentials.xxx as well as cloud.aws.region.xxx can be set in application.yml. The following is an example:

spring:
  cloud:
    aws:
      credentials:
        access-key: <aws credentials/access key> # Specifies the access key
        secret-key: <aws credentials/secret key> # Specifies the secret key
      region:
        static: us-east-1 # A static value for region used by auto-configured AWS clients (e.g.,
`eu-west-1`) as AWS credentials are valid in a context of a region.
auto: false

For more information regarding AWS Region, see AWS Regions.

Manual Configuration

The Connector for Amazon SNS does not support manual connection configuration as the Amazon SNS provider is not known in advance. In order to establish a connection with the Amazon SNS, it is essential to acquire a connection factory via a JNDI lookup. See Configuring Connection Details for information on using JNDI.

Connecting to Multiple Systems

To connect to multiple systems of a same type, use the multiple binder syntax.    

For example:

spring: 
  cloud:
    stream: 
      binders:
        
        # 1st solace binder in this example 
	 solace1:
          type: solace 
	   environment: 
	     solace: 
	       java:
        	 host: tcp://localhost:55555
         
	 # 2nd solace binder in this example 
	 solace2:
          type: solace 
          environment: 
            solace: 
	       java:
        	 host: tcp://other-host:55555
        
	 # The only sns binder 
	 sns1:
          type: sns
	   # Add `environment` property map here if you need to customize this binder. 
	   # But for this example, we'll assume that defaults are used.
          
	 # Required for internal use 
	 undefined:
          type: undefined 
	 bindings:
          input-0:
            destination: <input-destination> 
	     binder: sns1
          output-0:
            destination: <output-destination>
            binder: solace1 # Reference 1st solace binder 
	   input-1:
            destination: <input-destination> 
	     binder: sns1
          output-1:
            destination: <output-destination>
            binder: solace2 # Reference 2nd solace binder

The configuration above defines two binders of type solace and one binder of type sns, which are then referenced within the bindings.

Each binder above is configured independently under spring.cloud.stream.binders.<bindername>.environment..