Introducing Camel-Nats

In the latest version of Apache Camel (2.17.0) we released camel-nats. NATS, is a cloud-native messaging system from Apcera. The first version of the component was based on java_nats, this library has been deprecated from a while and we decide to switch to the brand new client JNats in the next major release (Camel 2.18.0)

The component

Camel-Nats provides both producing/consuming endpoints. These are the options you can define:

• servers - a list of comma separated gnatsd servers
• topic - The topic name you want to use
• reconnect - Whether or not using reconnection feature (default true)
• pedantic - Whether or not running in pedantic mode (default false)
• verbose - Whether or not running in verbose mode (default false)
• ssl - Whether or not using SSL (default false)
• reconnectTimeWait - Waiting time before attempts reconnection (in milliseconds, default 3000)
• maxReconnectAttempts - Max reconnection attempts (default 3)
• pingInterval - Ping interval to be aware if connection is still alive (in milliseconds, default 4000)
• noRandomizeServers - Whether or not randomizing the order of servers for the connection attempts (default false)
• queueName - The Queue name if we are using nats for a queue configuration (consumer only)
• maxMessages - Stop receiving messages from a topic we are subscribing to after maxMessages (default unlimited, consumer only)
• poolSize - Consumer pool size (default 10, consumer only)

For more information about Nats configuration take a look at the docs

Examples

From the producer perspective:

from("direct:send").to("nats://localhost:4222?topic=test");

while from the consumer perspective you can have:

from("nats://localhost:4222?topic=test&maxMessages=5").to("mock:result")

In this case you will consume messages from the topic test until you received 5 messages.

The message from the consumer will have two headers:

• CamelNatsMessageTimestamp, the timestamp of the consumed message
• CamelNatsSubscriptionId, the Subscription Id of the consumer