Chapter 239. Nats Component Available as of Camel version 2.17 NATS is a fast and reliable messaging platform. Maven users will need to add the following dependency to their pom.xml for this component. <dependency> <groupId>org.apache.camel</groupId> <artifactId>camel-nats</artifactId> <!-- use the same version as your Camel core version --> <version>x.y.z</version> </dependency> 239.1. URI format nats:servers[?options] Where servers represents the list of NATS servers. 239.2. Options The Nats component supports 2 options, which are listed below. Name Description Default Type useGlobalSslContext Parameters (security) Enable usage of global SSL context parameters. false boolean resolveProperty Placeholders (advanced) Whether the component should resolve property placeholders on itself when starting. Only properties which are of String type can use property placeholders. true boolean The Nats endpoint is configured using URI syntax: with the following path and query parameters: 239.2.1. Path Parameters (1 parameters): Name Description Default Type servers Required URLs to one or more NAT servers. Use comma to separate URLs when specifying multiple servers. String 239.2.2. Query Parameters (25 parameters): Name Description Default Type connection (common) Reference an already instantiated connection to Nats server Connection connectionTimeout (common) Timeout for connection attempts. (in milliseconds) 2000 int flushConnection (common) Define if we want to flush connection or not false boolean flushTimeout (common) Set the flush timeout (in milliseconds) 1000 int maxPingsOut (common) maximum number of pings have not received a response allowed by the client 2 int maxReconnectAttempts (common) Max reconnection attempts 60 int noEcho (common) Turn off echo. If supported by the gnatsd version you are connecting to this flag will prevent the server from echoing messages back to the connection if it has subscriptions on the subject being published to. false boolean noRandomizeServers (common) Whether or not randomizing the order of servers for the connection attempts false boolean pedantic (common) Whether or not running in pedantic mode (this affects performace) false boolean pingInterval (common) Ping interval to be aware if connection is still alive (in milliseconds) 120000 int reconnect (common) Whether or not using reconnection feature true boolean reconnectTimeWait (common) Waiting time before attempts reconnection (in milliseconds) 2000 int requestCleanupInterval (common) Interval to clean up cancelled/timed out requests. 5000 int topic (common) Required The name of topic we want to use String verbose (common) Whether or not running in verbose mode false boolean bridgeErrorHandler (consumer) Allows for bridging the consumer to the Camel routing Error Handler, which mean any exceptions occurred while the consumer is trying to pickup incoming messages, or the likes, 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 maxMessages (consumer) Stop receiving messages from a topic we are subscribing to after maxMessages String poolSize (consumer) Consumer pool size 10 int queueName (consumer) The Queue name if we are using nats for a queue configuration String exceptionHandler (consumer) To let the consumer use a custom ExceptionHandler. Notice if the option bridgeErrorHandler is enabled then 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 replySubject (producer) the subject to which subscribers should send response String synchronous (advanced) Sets whether synchronous processing should be strictly used, or Camel is allowed to use asynchronous processing (if supported). false boolean secure (security) Set secure option indicating TLS is required false boolean sslContextParameters (security) To configure security using SSLContextParameters SSLContextParameters 239.3. Spring Boot Auto-Configuration The component supports 3 options, which are listed below. Name Description Default Type camel.component.nats.enabled Enable nats component true Boolean camel.component.nats.resolve-property-placeholders Whether the component should resolve property placeholders on itself when starting. Only properties which are of String type can use property placeholders. true Boolean camel.component.nats.use-global-ssl-context-parameters Enable usage of global SSL context parameters. false Boolean 239.4. Headers Name Type Description CamelNatsMessageTimestamp long The timestamp of a consumed message. Producer example: from("direct:send").to("nats://localhost:4222?topic=test"); In case of using Authorization you can directly specify your credentials in the server URL from("direct:send").to("nats://username:password@localhost:4222?topic=test"); or your token from("direct:send").to("nats://token@localhost:4222?topic=test"); Consumer example: from("nats://localhost:4222?topic=test&maxMessages=5&queueName=test").to("mock:result");

Commands:
<dependency> <groupId>org.apache.camel</groupId> <artifactId>camel-nats</artifactId> <!-- use the same version as your Camel core version --> <version>x.y.z</version> </dependency>
nats:servers[?options]
nats:servers
from("direct:send").to("nats://localhost:4222?topic=test");
from("direct:send").to("nats://username:password@localhost:4222?topic=test");
from("direct:send").to("nats://token@localhost:4222?topic=test");
from("nats://localhost:4222?topic=test&maxMessages=5&queueName=test").to("mock:result");