ProducerTemplate and Direct:start in camel - apache

Question

My camel route is :
from("direct:start")
.to("http://myhost/mypath");
I used :
ProducerTemplate template;
template.sendBody("direct:start", "This is a test message");
to send the exchange. I am getting following exception:
No consumers available on endpoint: Endpoint[direct://start].
How can i receive the same exchange in direct:start endpoint?

Answer 1

The reason you get this error is because you have not configured a Route that starts from direct:start.
If you have configured the Route, but did not mention it in your original query, then the next step to try is to first start the Camel Context, before calling the sendBody method.
camelContext.start();
template.sendBody("direct:start", "This is a test message");
Hope this resolves your issue.

Answer 2

I know this a very old question. But writing this for anyone who're still getting this kind of issue.
Scenario: During the process of a http GET method call, I am fetching some data from DB in the middle of the process and putting the data as message on to an artemis producer.
Firstly, if you're using camel with spring - you don't need to create any camel context at all. Because spring is smart enough to create camel context for you with below dependencies.
Few necessary dependencies:
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-artemis</artifactId>
</dependency>
<dependency>
<groupId>org.apache.camel</groupId>
<artifactId>camel-spring-boot-starter</artifactId>
<version>2.24.2</version>
</dependency>
<dependency>
<groupId>org.apache.camel</groupId>
<artifactId>camel-jaxb-starter</artifactId>
<version>2.24.2</version>
</dependency>
<dependency>
<groupId>org.apache.camel</groupId>
<artifactId>camel-jms</artifactId>
<version>2.24.2</version>
</dependency>
<dependency>
<groupId>org.apache.camel</groupId>
<artifactId>camel-jackson-starter</artifactId>
<version>2.24.2</version>
</dependency>
<dependency>
<groupId>org.apache.camel</groupId>
<artifactId>camel-core</artifactId>
<version>2.24.2</version>
</dependency>
<dependency>
<groupId>org.apache.camel</groupId>
<artifactId>camel-amqp</artifactId>
<version>2.24.2</version>
</dependency>
So to fix it, I created a class that extends RouteBuilder class from camel library. In this builder, I created a dummy consumer and used it to send message to an actual producer. My destination is an artemis producer endpoint.
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.SerializationFeature;
import com.fasterxml.jackson.datatype.jsr310.JavaTimeModule;
import org.apache.camel.LoggingLevel;
import org.apache.camel.builder.RouteBuilder;
import org.apache.camel.component.jackson.JacksonDataFormat;
import org.apache.camel.spi.DataFormat;
import org.springframework.stereotype.Component;
#Component
public class MyRouteBuilder extends RouteBuilder {
private DataFormat marshalDataFormat;
public MyRouteBuilder(ObjectMapper objectMapper) {
objectMapper.registerModule(new JavaTimeModule());
objectMapper.configure(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS, false);
marshalDataFormat = new JacksonDataFormat(objectMapper, MyClass.class);
}
#Override
public void configure() throws Exception {
from("direct:imaginary-consumer")
.marshal(marshalDataFormat)
.log(LoggingLevel.INFO, "Message ready to send is ${body}")
.to("producer:message-data")
.log(LoggingLevel.INFO, "Message has been sent successfully to topic.");
}
}
Below snippet is in any implementation class that carries the message body. This method takes message data and send it to the imaginary/dummy consumer we created in MyRouteBuilder class. The router class gets invoked and sends the message to the destination (producer here). It can be to http endpoints as well.
#Autowired
private ProducerTemplate producerTemplate;
public void sendMessage(Map<String, MyClass> messageBody) {
producerTemplate.sendBody("direct:imaginary-consumer", messageBody);
}

Answer 3

This is also posted on the Apache Camel mailing list, where its active being discussed.
http://camel.465427.n5.nabble.com/ProducerTemplate-and-direct-start-in-camel-tp5730558.html