Rest DSL的restConfiguration如何从jetty.xml动态注入Jetty端口及camel-jetty配置疑问

Great questions! Let's break this down step by step for your JBoss Fuse setup:

1. Dynamic Injection of Jetty Port from jetty.xml #

Absolutely, you can dynamically inject the Jetty port value into jetty.xml to support unique port configurations across your containers. Here's how to do it properly:

Key Approach: Use OSGi Property Placeholders #

JBoss Fuse leverages OSGi Config Admin for externalized configuration, so you can replace hardcoded ports in jetty.xml with placeholders that pull values from container-specific configuration files:

1. Update your jetty.xml to use a placeholder for the port:

   <!-- Example snippet from jetty.xml -->
   <Call name="addConnector">
     <Arg>
         <New class="org.eclipse.jetty.server.ServerConnector">
             <Arg name="server"><Ref refid="Server"/></Arg>
             <!-- Use a placeholder with a default value -->
             <Set name="port">${jetty.port:8181}</Set>
         </New>
     </Arg>
   </Call>
   

2. For each container, create or modify a configuration file (e.g., etc/org.myapp.jetty.cfg) to define the unique port:

   jetty.port=8282
   

3. Ensure your Fuse instance loads these properties by registering the configuration file with OSGi Config Admin (this is typically handled automatically for files in the etc/ directory).

Accessing the Port in Code #

If you need to reference this same port value in your application code (like your Camel route), you can fetch it from the OSGi Config Admin service or use Camel's built-in property placeholder support.

2. Camel-Jetty Component and jetty.xml Configuration #

By default, the camel-jetty component does not automatically read port values from jetty.xml. Here's why and how to fix it:

Why It Doesn't Auto-Read #

The camel-jetty component spins up its own embedded Jetty server instance by default, separate from the Jetty instance configured via jetty.xml for JBoss Fuse's core services. This means it won't inherit port settings from that file unless you explicitly wire them together.

How to Sync the Configuration #

You have two options to align camel-jetty with your jetty.xml port:

Option 1: Explicitly Pass the Port Value in Your Camel Route

Use the same property placeholder approach to pull the port value into your Camel restConfiguration:

@Override
public void configure() throws Exception {
    restConfiguration()
        .component("jetty")
        .host("localhost")
        // Use Camel's property placeholder to reference the same port from OSGi config
        .port("{{jetty.port:8181}}")
        .scheme("https")
        .bindingMode(RestBindingMode.json);

    // Define your REST routes below
    rest("/api")
        .get("/hello")
        .to("direct:hello");
}

Option 2: Reuse JBoss Fuse's Existing Jetty Instance

If you want camel-jetty to use the same Jetty server configured in jetty.xml (instead of starting a new one), you can wire the existing server instance to the Camel component:

1. In your Blueprint/Spring configuration, reference the existing Jetty server:

   <!-- Look up the Jetty server instance from JBoss Fuse's OSGi registry -->
   <reference id="jettyServer" interface="org.eclipse.jetty.server.Server"/>
   
   <camelContext xmlns="http://camel.apache.org/schema/blueprint">
       <restConfiguration component="jetty" host="localhost" scheme="https">
           <!-- Tell camel-jetty to use the existing server -->
           <componentProperty key="jettyServer" valueRef="jettyServer"/>
       </restConfiguration>
       <!-- Your routes here -->
   </camelContext>
   

   With this setup, camel-jetty will use the port already configured in jetty.xml—no need to set it manually in the route.

内容的提问来源于stack exchange，提问作者GLMills