Apache Camel 3.x Upgrade Guide

This document is for helping you upgrade your Apache Camel application from Camel 3.x to 3.y. For example if you are upgrading Camel 3.0 to 3.2, then you should follow the guides from both 3.0 to 3.1 and 3.1 to 3.2.

Upgrading Camel 3.1 to 3.2

JndiRegistry

The deprecated class org.apache.camel.impl.JndiRegistry has been removed. The class org.apache.camel.support.jndi.JndiBeanRepository located in org.apache.camel:camel-support should be used instead.

Rest Configuration

The rest configuration has been simplified and there is now a single RestConfiguration instance (CAMEL-13844) per Camel Context.

The following methods have been removed:

  • org.apache.camel.CamelContext#addRestConfiguration(RestConfiguration restConfiguration)

  • org.apache.camel.CamelContext#getRestConfiguration(String component, boolean defaultIfNotFound)

  • org.apache.camel.CamelContext#getRestConfigurations

https://issues.apache.org/jira/browse/CAMEL-13844

Camel Cloud

The following ServiceDiscovery implementation has been removed:

  • org.apache.camel.impl.cloud.CachingServiceDiscovery

  • org.apache.camel.impl.cloud.CachingServiceDiscoveryFactory

https://issues.apache.org/jira/browse/CAMEL-14813

Camel with Karaf and OSGi

Camel on Apache Karaf / OSGi has been moved to its own project at: https://github.com/apache/camel-karaf

The Maven dependencies has changed the groupid from org.apache.camel to org.apache.camel.karaf.

For example the camel-blueprint would be changed from

<dependency>
  <groupId>org.apache.camel</groupId>
  <artifactId>camel-blueprint</artifactId>
  <version>3.1.0</version>
</dependency>

To:

<dependency>
  <groupId>org.apache.camel.karaf</groupId>
  <artifactId>camel-blueprint</artifactId>
  <version>3.2.0</version>
</dependency>

The Camel Karaf features are the same as before, you can still install Camel in Karaf shell via:

feature:repo-add camel 3.2.0
feature:install camel

Other components involved

  • Camel-test-blueprint

<dependency>
  <groupId>org.apache.camel</groupId>
  <artifactId>camel-test-blueprint</artifactId>
  <version>3.1.0</version>
</dependency>

To:

<dependency>
  <groupId>org.apache.camel.karaf</groupId>
  <artifactId>camel-test-blueprint</artifactId>
  <version>3.2.0</version>
</dependency>

  • Camel-test-karaf

<dependency>
  <groupId>org.apache.camel</groupId>
  <artifactId>camel-test-karaf</artifactId>
  <version>3.1.0</version>
</dependency>

To:

<dependency>
  <groupId>org.apache.camel.karaf</groupId>
  <artifactId>camel-test-karaf</artifactId>
  <version>3.2.0</version>
</dependency>

  • Camel-eventadmin

<dependency>
  <groupId>org.apache.camel</groupId>
  <artifactId>camel-eventadmin</artifactId>
  <version>3.1.0</version>
</dependency>

To:

<dependency>
  <groupId>org.apache.camel.karaf</groupId>
  <artifactId>camel-eventadmin</artifactId>
  <version>3.2.0</version>
</dependency>

  • Camel-kura

<dependency>
  <groupId>org.apache.camel</groupId>
  <artifactId>camel-kura</artifactId>
  <version>3.1.0</version>
</dependency>

To:

<dependency>
  <groupId>org.apache.camel.karaf</groupId>
  <artifactId>camel-kura</artifactId>
  <version>3.2.0</version>
</dependency>

  • Camel-osgi-activator

<dependency>
  <groupId>org.apache.camel</groupId>
  <artifactId>camel-osgi-activator</artifactId>
  <version>3.1.0</version>
</dependency>

To:

<dependency>
  <groupId>org.apache.camel.karaf</groupId>
  <artifactId>camel-osgi-activator</artifactId>
  <version>3.2.0</version>
</dependency>

  • Camel-paxlogging

<dependency>
  <groupId>org.apache.camel</groupId>
  <artifactId>camel-paxlogging</artifactId>
  <version>3.1.0</version>
</dependency>

To:

<dependency>
  <groupId>org.apache.camel.karaf</groupId>
  <artifactId>camel-paxlogging</artifactId>
  <version>3.2.0</version>
</dependency>

Introducing a camel-karaf-bom

We introduce a camel-karaf-bom too, so the end-users should be able to have all of this dependencies easier:

    <dependencyManagement>
        <dependencies>
            <!-- Add Camel BOM -->
            <dependency>
                <groupId>org.apache.camel</groupId>
                <artifactId>camel-bom</artifactId>
                <version>${project.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
            <!-- Add Camel Karaf BOM -->
            <dependency>
                <groupId>org.apache.camel.karaf</groupId>
                <artifactId>camel-karaf-bom</artifactId>
                <version>${camel.karaf.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>

In this way you’ll get both the boms and all the "goodies"

camel-elytron

Transitive dependencies from org.wildfly.security:wildfly-elytron were removed.

camel-spark-rest

This component has been removed. Use any of the other REST capable components, such as camel-jetty, camel-netty-http or camel-undertow.

EIPs with cacheSize option

The cacheSize option on EIPs has been improved to reduce memory usage when the cache is disabled by setting the value to -1. One of the optimizations is that new endpoints will not be added to the endpoint registry, but discarded after use. This avoids storing additional endpoints in the cache (memory) as the cache should be disabled (cacheSize=-1).

See more details in the documentation for the cacheSize option on the EIPs.

Configuring components via Java setters

Configuring Camel components from plain Java code has changed in some components where they were using delegate setters for a nested configuration class. These delegates has been removed, to ensure configuration is more consistent and aligned with how endpoints is configured as well, and by using source code generated configurer classes.

The following Camel components has been affected and changed on the component level:

  • camel-aws

  • camel-aws2

  • camel-consul

  • camel-etcd

  • camel-infinispan

  • camel-kafka

  • camel-servicenow

  • camel-ssh

  • camel-stomp

  • camel-xmlsecurity

  • camel-yammer

This only affects if you are configuring these components using Java code or XML <bean> style.

For example

KafkaComponent kafka = new KafkaComponent();
kafka.setBrokers("mybroker1:1234,mybroker2:1234");

Should now be:

KafkaComponent kafka = new KafkaComponent();
kafka.getConfiguration().setBrokers("mybroker1:1234,mybroker2:1234");

And in XML:

<bean id="kafka" class="org.apache.camel.component.kafka.KafkaComponent">
  <property name="brokers" value="mybroker1:1234,mybroker2:1234"/>
</bean>

Should now be:

<bean id="kafka" class="org.apache.camel.component.kafka.KafkaComponent">
  <property name="configuration">
    <property name="brokers" value="mybroker1:1234,mybroker2:1234"/>
  </property>
</bean>

Configuring components via Spring Boot auto configuration

Configuring Camel spring boot components has changed its option keys to be flattened and have the .configuration prefix removed now.

Before in application.properties

camel.component.kafka.configuration.brokers=mybroker1:1234,mybroker2:1234

Should now be

camel.component.kafka.brokers=mybroker1:1234,mybroker2:1234

This applies to all the Camel spring boot starter JARs where basically .configuration should be removed.

Configuring camel-activemq, camel-amqp and camel-stomp via Spring Boot auto configuration

When configuring these components from spring boot auto-configuration then the URL for the broker was named broker-u-r-l in the spring boot auto configuration support. This has been renamed to broker-url and a few other options too.

Before:

camel.component.activemq.broker-u-r-l=tcp://localhost:61616

After:

camel.component.activemq.broker-url=tcp://localhost:61616

camel-any23

The XML DSL has changed for the <configuration> element, which now is flattened so the key/values should be configured on it directly:

Before:

<dataFormats>
  <any23 id="any23" baseURI ="http://mock.foo/bar" outputFormat="TURTLE" >
    <configuration>
      <property key="any23.extraction.metadata.nesting" value="off" />
      <property key="another-key" value="another-value" />
    </configuration>
    <extractors>html-head-title</extractors>
  </any23>
</dataFormats>

After:

<dataFormats>
  <any23 id="any23" baseURI ="http://mock.foo/bar" outputFormat="TURTLE" >
    <configuration key="any23.extraction.metadata.nesting" value="off"/>
    <configuration key="another-key" value="another-value"/>
    <extractors>html-head-title</extractors>
  </any23>
</dataFormats>

camel-avro

The avro component and data format has been split up into two JARs. The dataformat is in camel-avro JAR and the component in camel-avro-rpc JAR.

camel-infinispan

Camel now requires endpoint URIs to include context-path which means the endpoint URI infinispan should be changed to infinispan:current.

google-pubnub

The google-pubnub component has been improved to use a new Java library and become faster.

Support for Apache Karaf has been removed.

camel-xstream

The XML DSL has changed for the <converters>, <alias>, implicitCollections, and omitFields elements, which now is flattened so the key/values should be configured on it directly.

Before:

<xstream id="xstream-1" mode="NO_REFERENCES"
    permissions="-org.apache.camel.dataformat.xstream.*,org.apache.camel.dataformat.xstream.PurchaseHistory,org.apache.camel.dataformat.xstream.PurchaseOrder">
    <converters>
        <converter class="org.apache.camel.dataformat.xstream.XStreamConfigurationTest$PurchaseOrderConverter" />
    </converters>
    <aliases>
                <alias name="purchase-order" class="org.apache.camel.dataformat.xstream.PurchaseOrder" />
    </aliases>
    <implicitCollections>
       <class name="org.apache.camel.dataformat.xstream.PurchaseHistory">
          <field>history</field>
       </class>
    </implicitCollections>
</xstream>

After:

<xstream id="xstream-1" mode="NO_REFERENCES"
    permissions="-org.apache.camel.dataformat.xstream.*,org.apache.camel.dataformat.xstream.PurchaseHistory,org.apache.camel.dataformat.xstream.PurchaseOrder">
    <converters key="purchase-converter" value="org.apache.camel.dataformat.xstream.XStreamConfigurationTest$PurchaseOrderConverter"/>
    <aliases key="purchase-order" value="org.apache.camel.dataformat.xstream.PurchaseOrder"/>
    <implicitCollections key="org.apache.camel.dataformat.xstream.PurchaseHistory" value="history"/>
</xstream>

Multiple values for implicitCollections and omitFields can be separated by comma

For example:

<implicitCollections key="org.apache.camel.dataformat.xstream.PurchaseHistory" value="history,adress"/>

camel-weather

This component has been upgraded from using Apache Http Client 3.x to 4.x and is therefore not fully backwards compatible. Some options for configurer and setting proxy is removed. You can however configure this directly on a custom HttpClient instance and set this on the WeatherComponent to use.

Endpoint URIs without context path

Previously Camel components may work by referring to their name only without a colon and context path (eg log) that for a few components would allow them to create an endpoint anyway.

Now this is not allowed and Camel will throw an NoSuchEndpointException.

An endpoint by its logical id can still be referred by the id only, eg

Endpoint endpoint = camelContext.getEndpoint("myCoolEndpoint");

Error handling

The context scope error handling has been modified a bit. The processors in those onException and onCompletion are not shared between routes anymore. This should have little effect in most cases. If there is a need to have a single set of processors involved (such as when using a loadbalancer or other stateful patterns), then an intermediary route needs to be used. The following excerpt:

onException(Exception.class).handled(true)
    .loadBalance().roundRobin().id("round")
    .to("mock:error", "mock:error2", "mock:error3");

  1. needs to be rewritten as:

onException(Exception.class).handled(true).to("direct:error");

from("direct:error").loadBalance().roundRobin().id("round")
    .to("mock:error", "mock:error2", "mock:error3");

camel-cluster

The base support for cluster in org.apache.camel.cluster has been moved out of camel-core-engine into separate JAR named camel-cluster.

Configuring milli seconds

If upgrading to Camel 3.4 or newer then do NOT do this because Camel 3.4 adds back support for this.

Camel was using a type converter from String → long that accepted a time pattern which allowed to configure long values such as 2s for 2 seconds, e.g. 2000. And more complex such as 8h15m for 8 hours and 15 minutes.

However as this was implemented as part of String → long type conversion which then adds a little bit of overhead during routing, when converting from String to plain numbers.

To make Camel routing engine as fast as possible this feature has been removed.

For example a timer with a 5 second period

from("timer:foo?period=5s")

Should now be specified as numeric only:

from("timer:foo?period=5000")

Main in camel-spring

The org.apache.camel.spring.Main class has been moved out of camel-spring JAR into its own JAR named camel-spring-main.

Main in camel-test-blueprint

The org.apache.camel.test.blueprint.Main class has been renamed to org.apache.camel.test.blueprint.Main and moved into its own camel-test-blueprint JAR.

To use the camel-maven-plugin goal camel:run with OSGi plugin, you now need to add the following dependency to the classpath org.apache.camel.karaf:camel-blueprint-main.

API changes

DefaultComponent

The deprecated method preProcessUri has been removed.

CamelContext

The method getEndpoint now throws NoSuchEndpointException directly instead of being wrapped within an FailedToResolveEndpoint.

JavaUuidGenerator

The org.apache.camel.impl.engine.JavaUuidGenerator class has been removed. Its a very slow UUID generator and its not recommended to be used.

PropertiesComponent

The org.apache.camel.component.properties.PropertiesFunction has been moved to org.apache.camel.spi.PropertiesFunction and its now possible to add custom functions on the org.apache.camel.spi.PropertiesComponent interface.

JMX Connector configuration removed

The JMX Connector configuration in camel-management has been removed in Camel 3.2.0. If you want to support the ability to use JMX with Camel remotely, then just use the default JVM JMX remote capabilities. For example, use the following (insecure) JVM settings to be able to manage Camel remotely on localhost, port 9913:

-Dcom.sun.management.jmxremote.port=9913
-Dcom.sun.management.jmxremote.authenticate=false
-Dcom.sun.management.jmxremote.ssl=false
-Djava.rmi.server.hostname=localhost