Velocity Support

[dc2tom]

Our team make use of camel-velocity for running message transformations. It would be great to see a camel-quarkus extension supporting velocity.

[ppalaga]

A contribution is welcome. You may want to follow https://camel.apache.org/camel-quarkus/latest/contributor-guide.html if you are interested. There is also a PR with Freemarker support under review #835 that may have vast similarities to velocity.

[zhfeng]

I can take a look at this issue.

[dc2tom]

Happy to collaborate on this @zhfeng if I get a chance - that Freemarker pull request does look to have a lot of similarities

[zhfeng]

@dc2tom it should be very similar to the freemarker component. At first, you need to create the velocity extension by mvn cq:create -N -Dcq.artifactIdBase=velocity. The followup steps could do

• enable the reflective class of the Exchanges in VelocityProcessor.java

  reflectiveClass.produce(new ReflectiveClassBuildItem(false, false, Exchanges.class);
  

  so the ${exchange.properties} can be used in the vm files.
• add the option of quarkus.camel.velocity.classModules=<list of the classes which could be used in the template file> in the runtime of VelocityConfig just like freemarkers and process these class just like the Exchanges class above.
• add the option to scan all of the vm files and add them into the native image resources.
• check the integration test and make sure it work
• re-gen the docs by mvn process-resources -Pformat

anyway, you are welcome to contribute a PR. Feel free to ask here and I will try my best to help you !

[dc2tom]

Hi, I've made a start with this following the Freemarker pull request as an example. I'm working on porting over the unit tests from camel-velocity but there is one thing I'm not getting.

When trying to run my test, against the below resource definition

@Path("/velocity")
@ApplicationScoped
public class VelocityLetterResource {

    @Inject
    ProducerTemplate producerTemplate;

    @Path("/velocityLetter")
    @POST
    @Consumes(MediaType.APPLICATION_JSON)
    @Produces(MediaType.TEXT_PLAIN)
    public String post(String message) {
        Exchange exchange = producerTemplate.request("direct:a", new Processor() {
            @Override
            public void process(Exchange exchange) throws Exception {
                exchange.getIn().setHeader("firstName", "Claus");
                exchange.getIn().setHeader("lastName", "Ibsen");
                exchange.getIn().setHeader("item", "Camel in Action");
                exchange.getIn().setBody("PS: Next beer is on me, James");
            }
        });

        return (String) exchange.getOut().getBody();
    }

public static class VelocityRouteBuilder extends RouteBuilder {
        @Override
        public void configure() {
            from("direct:a")
                    .to("velocity:org/apache/camel/quarkus/component/velocity/letter.vm");
        }
    }

I see the following failure:

Caused by: org.apache.camel.NoSuchEndpointException: No endpoint could be found for: direct://a, please check your classpath contains the needed Camel component jar.

I can't work out how the RouteBuilder is invoked - my integration tests exist in the org.apache.camel.quarkus.component.velocity.it package.. I auto generated the velocity extension as per the contribution guide.

I expected that perhaps my extension would not be able to load the .vm file as I have yet to implement the functionality, but instead it seems the RouteBuilder is not being executed. Any advice appreciated :)

[ppalaga]

Sounds like your integration test module is missing the camel-quarkus-direct dependency.

[dc2tom]

Perfect, thanks for the quick response, I'm now in a position to work through porting the rest of the camel-velocity test over.

Hopefully I can have a pull request ready in the near future.

[ppalaga]

Any progress on this one @dc2tom? I am about to add an auto-generated JVM-only Velocity extension. If you had an integration test ready, going native would be easy.

[dc2tom]

I've created a pull request with what I had so far #1634

Unfortunately due to other commitments I wasn't able to progress this further than what I've just uploaded

[JiriOndrusek]

@ppalaga I can look at this issue, please assign it to me.

[JiriOndrusek]

@zhfeng I've missed your involvement at this issue. Do you plan to continue with it or are you working on it? May I help?

[zhfeng]

Hi @JiriOndrusek , feel free to take this issue.

[ppalaga]

Fixed via #1804