CODEWITHSUNDEEP
apache-camelweblogic12c
rodrigocoelho
rodrigocoelho

Reputation: 128

Camel not passing Exchange properties

i need to pass some parameters on the properties of the Exchange object. As far as i know and read about it, it's better to create my parameters on the exchange properties, because the headers of the message can change during routing. Camel is creating new exchange from route to route, but not preserving history of any of my parameters.

Now some context: I'm using Camel (2.16.1) deployed on WebLogic 12C

The relevant Maven part:

<properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <camel.version>2.16.1</camel.version>
  </properties>

  <dependencies>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-web</artifactId>
            <version>4.1.6.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.apache.camel</groupId>
            <artifactId>camel-core</artifactId>
            <version>${camel.version}</version>
        </dependency>
        <dependency>
            <groupId>org.apache.camel</groupId>
            <artifactId>camel-spring</artifactId>
            <version>${camel.version}</version>
        </dependency>
        <dependency>
            <groupId>org.apache.camel</groupId>
            <artifactId>camel-cxf</artifactId>
            <version>${camel.version}</version>
        </dependency>
        <dependency>
            <groupId>org.apache.camel</groupId>
            <artifactId>camel-jms</artifactId>
            <version>${camel.version}</version>
        </dependency>
        <dependency>
            <groupId>org.apache.camel</groupId>
            <artifactId>camel-test-spring</artifactId>
            <version>${camel.version}</version>
        </dependency>
        <dependency>
            <groupId>javax.ejb</groupId>
            <artifactId>ejb-api</artifactId>
            <version>3.0</version>
        </dependency>
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-api</artifactId>
            <version>1.7.13</version>
        </dependency>
    </dependencies>

The Camel Context:

<camelContext xmlns="http://camel.apache.org/schema/spring">
    <route>
        <from uri="file:/Users/user/camel-test/in?noop=false" />
        <process ref="TestProcess"/>
        <to uri="file:/Users/user/camel-test/out" />
    </route>
    <route>
        <from uri="file:/Users/user/camel-test/out?noop=false" />
        <process ref="TestProcess"/>
        <to uri="jms:CamelServer/CamelJMSModule!CamelQueue" />
    </route>
</camelContext>

As you can see i'm using a class called TestProcess, to affect the Exchange object like this:

package com.test.camel;

import org.apache.camel.Exchange;
import org.apache.camel.Processor;

public class TestProcess implements Processor {

    public void process(Exchange exchange) throws Exception {

        //Just to get the Exchange ID, this ID is changing between routes
        System.out.println(exchange.getExchangeId());

        //The first time i try to get my custom property should return null of course
        System.out.println(exchange.getProperty("MY_PARAMETER_ID"));

        //So if my property does not exist in properties i will create it
        if(exchange.getProperty("MY_PARAMETER_ID") == null) {
            exchange.setProperty("MY_PARAMETER_ID", "SOME_VALUE");  
        }
    }
}

My problem is: I never get my property on properties during all routing. My goal is to set some properties when Camel starts to route my message, and have those properties available till the end of process.

The class TestProcess demonstrates how i trying to access the properties. I also tried on the XML like, not working as well:

<camelContext xmlns="http://camel.apache.org/schema/spring">
    <route>
        <from uri="file:/Users/user/camel-test/in?noop=false" />
        <setProperty propertyName="MY_PARAMETER_ID">
                <simple>some-value</simple>
        </setProperty>
        <to uri="file:/Users/user/camel-test/out" />
    </route>
    <route>
        <from uri="file:/Users/user/camel-test/out?noop=false" />
        <log message="MY_PARAMETER_ID = ${header.MY_PARAMETER_ID}" />
        <to uri="jms:CamelServer/CamelJMSModule!CamelQueue" />
    </route>
</camelContext>

UPDATE: After a couple of you say that it was not possible to send property/header attributes from a file endpoint, just jms or direct, i tried using JMS but i still have the same problem, as you can see on the context:

<camelContext xmlns="http://camel.apache.org/schema/spring">
    <route>
        <from uri="jms:CamelServer/CamelJMSModule!ReceiverQueue" />
        <setProperty propertyName="MY_PARAMETER_ID">
            <simple>some-value</simple>
        </setProperty>
        <to uri="jms:CamelServer/CamelJMSModule!CamelQueue" />
    </route>
    <route>
        <from uri="jms:CamelServer/CamelJMSModule!CamelQueue" />
        <log message="MY_PARAMETER_ID = ${header.MY_PARAMETER_ID}" />
        <to uri="jms:CamelServer/CamelJMSModule!FinalQueue" />
    </route>
</camelContext>

Any ideas? What i'm doing wrong?

With the example where i'm only using JMS, the only attribute that didn't change from on Exchange object to the other is the:

exchange.getIn().getHeader("breadcrumbId")

According to Camel documentation this is:

Camel 2.8: An unique id used for tracking messages across transports.

But this breadcrumbId only remains the same with JMS routes NOT with FILE routes.

Thanks!

Upvotes: 0

Views: 4290

Answers (3)

FreemanB
FreemanB

Reputation: 51

Soilworker explained why it didn't work when using files between routes. When you switched to JMS, it is still sending just the message body by default. To send the entire exchange, you need to enable the transferExchange property on the JMS endpoints. It is in the documentation links included in his answer.

On that note, I'd personally recommend not transferring exchanges over external connections, and instead, use a format that allows you to pass any needed properties inside the message body. That will give you more flexibility in the long run and not tie you to specific delivery mechanisms.

Edit: Oops, should have checked the date on the original question. But since that part wasn't mentioned originally, I think it is useful to clarify why just switching to JMS wasn't sufficient.

Upvotes: 0

Souciance Eqdam Rashti
Souciance Eqdam Rashti

Reputation: 3191

Since you are using a new version of camel, this seems have happened. http://camel.apache.org/property.html

From Camel 2.15 onwards the property language has been renamed to exchangeProperty to avoid ambiguity, confusion and clash with properties as a general term. So use exchangeProperty instead of property when using Camel 2.15 onwards.

<route>
  <from uri="direct:a" />
  <recipientList>
    <exchangeProperty>myProperty</exchangeProperty>
  </recipientList>
</route>

Try in the xml dsl accessing the exchange property using the field instead.

Upvotes: -1

soilworker
soilworker

Reputation: 1337

Routing header/property values between 2 routes via file endpoints is not possible. Use for example direct endpoints or jms to communicate between 2 routes.

See http://camel.apache.org/direct.html or http://camel.apache.org/jms.html for more information.

Upvotes: 0

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