Question

I want to use Camel to take a message from ActiveMQ and then, based on the message contents (a protobuf), send one or more messages to Twitter. I’ve written a bean that is called from within a route and which uses injection to send multiple messages to a “direct:xyz” endpoint.

However, Camel is complaining at runtime that:

2012-11-16 09:56:33,376 | WARN  | ication.twitter] | DirectProducer                   | 160 - org.apache.camel.camel-core - 2.10.2 | No consumers available on endpoint: Endpoint[direct://twitter] to process: Exchange[Message: hello world]

If I instead inject directly to the Twitter endpoint from within the bean, it works fine. However, in order to ease testing, simplify configuration etc, I’d like to keep the actual Twitter config separate, hence wanting to send to a separate route.

The camel context config looks like:-

<camelContext id="NotificationTwitter"
    trace="false" xmlns="http://camel.apache.org/schema/blueprint">
    <dataFormats>
        <protobuf id="notificationProto" instanceClass="org.abc.schemas.protobuf.NotificationDef$NotificationMsg" />
    </dataFormats>

    <route id="TwitterPreparation">
        <from uri="activemq:notification.twitter" />
        <unmarshal ref="notificationProto" />
        <log logName="abc" loggingLevel="INFO"
            message="Twitter request received: ${body}" />
        <bean ref="NotificationTweeter" method="createTweets" />
    </route>

    <route id="Twitter">
        <from uri="direct:twitter" />
        <log logName="abc" loggingLevel="INFO"
            message="Tweeting: ${body}" />
        <to uri="twitter://timeline/user?consumerKey=itsasecret&amp;consumerSecret=itsasecret&amp;accessToken=itsasecret&amp;accessTokenSecret=itsasecret" />
    </route>
</camelContext>

The bean looks like:-

public class NotificationTweeter {

  @EndpointInject(uri = "direct:twitter")
  private ProducerTemplate producerTemplate;

  public void createTweets(NotificationMsg notification) {

    String tweet = notification.getMessageDetail().getTitle();

    try {
      // only send tweets where the notification message contains the Twitter mechanism
      for (MechanismMsg mechanism : notification.getMechanismList()) {
        if (mechanism.getType() == MechanismTypeEnum.TWITTER) {

          // Cycle round the recipients
          for (RecipientMsg recipient : mechanism.getRecipientList()) {
            tweet = "@" + recipient.getIdentifier() + " " + tweet;

            producerTemplate.sendBody(tweet);
          }

          // TODO exceptions if no recipients found, etc
        }
      }
    } catch (Exception ex) {
      ex.printStackTrace();
    }
  }
}

I’ve had this problem in other routes (it’s certainly not related to the Twitter feature) but have just worked around it. This time, however, I’d like to actually understand what the issue is! Any help gratefully received, thanks.

Answer 1

It sounds like a problem with the startup ordering of your routes. See more detail here http://camel.apache.org/configuring-route-startup-ordering-and-autostartup.html

You can configure the “direct” route to start before the other route, then that issue should be resolved.