CAMEL-19308: Add minimal support of native mode

[essobedo]

fix for https://issues.apache.org/jira/browse/CAMEL-19308

Motivation

Spring Boot 3 proposes the native mode out of the box, we would like to allow Camel SB users to leverage this new feature to build native images from routes written using the Java, XML, and/or YAML DSL.

Modifications:

• Workarounds the limitations of the native mode that prevented a Camel SB application from starting in native mode
• Adds a new starter for JAXB to be able to provide the hints/substitutions required for the native mode. The code is more or less equivalent to what is done in the JAXB extension of Quarkus (Needed for the XML DSL)
• Adds general hints required for a Camel SB application

Result

Simple routes (without complex components) written in Java, XML, and YAML DSL can be compiled and launched in native mode.

JVM mode

2023-06-16T18:38:25.323+02:00  INFO 6783 --- [           main] c.e.cameldemo.CameldemoApplication       : Starting CameldemoApplication using Java 17.0.7 with PID 6783 (/Users/nicolasfilotto/test/cameldemo/target/classes started by nicolasfilotto in /Users/nicolasfilotto/test/cameldemo)
2023-06-16T18:38:25.327+02:00  INFO 6783 --- [           main] c.e.cameldemo.CameldemoApplication       : No active profile set, falling back to 1 default profile: "default"
2023-06-16T18:38:27.189+02:00  INFO 6783 --- [           main] o.a.c.impl.engine.AbstractCamelContext   : Apache Camel 4.0.0-SNAPSHOT (camel-1) is starting
2023-06-16T18:38:27.202+02:00  INFO 6783 --- [           main] c.s.b.CamelSpringBootApplicationListener : Starting CamelMainRunController to ensure the main thread keeps running
2023-06-16T18:38:27.202+02:00  INFO 6783 --- [inRunController] org.apache.camel.main.MainSupport        : Apache Camel (Main) 4.0.0-SNAPSHOT is starting
2023-06-16T18:38:27.212+02:00  INFO 6783 --- [           main] o.a.c.impl.engine.AbstractCamelContext   : Routes startup (started:8)
2023-06-16T18:38:27.212+02:00  INFO 6783 --- [           main] o.a.c.impl.engine.AbstractCamelContext   :     Started MyCamelRouter (timer://hello)
2023-06-16T18:38:27.213+02:00  INFO 6783 --- [           main] o.a.c.impl.engine.AbstractCamelContext   :     Started timer-route (timer://myTimer)
2023-06-16T18:38:27.213+02:00  INFO 6783 --- [           main] o.a.c.impl.engine.AbstractCamelContext   :     Started route1 (timer://yaml)
2023-06-16T18:38:27.213+02:00  INFO 6783 --- [           main] o.a.c.impl.engine.AbstractCamelContext   :     Started hello (timer://hello)
2023-06-16T18:38:27.213+02:00  INFO 6783 --- [           main] o.a.c.impl.engine.AbstractCamelContext   :     Started route6 (timer://one)
2023-06-16T18:38:27.213+02:00  INFO 6783 --- [           main] o.a.c.impl.engine.AbstractCamelContext   :     Started route7 (timer://deux)
2023-06-16T18:38:27.213+02:00  INFO 6783 --- [           main] o.a.c.impl.engine.AbstractCamelContext   :     Started route8 (timer://one)
2023-06-16T18:38:27.213+02:00  INFO 6783 --- [           main] o.a.c.impl.engine.AbstractCamelContext   :     Started route9 (timer://deux)
2023-06-16T18:38:27.213+02:00  INFO 6783 --- [           main] o.a.c.impl.engine.AbstractCamelContext   : Apache Camel 4.0.0-SNAPSHOT (camel-1) started in 22ms (build:0ms init:0ms start:22ms)
2023-06-16T18:38:27.223+02:00  INFO 6783 --- [           main] c.e.cameldemo.CameldemoApplication       : Started CameldemoApplication in 2.273 seconds (process running for 2.618)

8 routes (a mix of Java, XML, and YAML) started in a little bit less than 3 seconds

Native mode

2023-06-16T18:37:28.868+02:00  INFO 6562 --- [           main] c.e.cameldemo.CameldemoApplication       : Starting AOT-processed CameldemoApplication using Java 17.0.7 with PID 6562 (/Users/nicolasfilotto/test/cameldemo/target/cameldemo started by nicolasfilotto in /Users/nicolasfilotto/test/cameldemo)
2023-06-16T18:37:28.868+02:00  INFO 6562 --- [           main] c.e.cameldemo.CameldemoApplication       : No active profile set, falling back to 1 default profile: "default"
2023-06-16T18:37:29.173+02:00  INFO 6562 --- [           main] o.a.c.impl.engine.AbstractCamelContext   : Apache Camel 4.0.0-SNAPSHOT (camel-1) is starting
2023-06-16T18:37:29.173+02:00  INFO 6562 --- [           main] c.s.b.CamelSpringBootApplicationListener : Starting CamelMainRunController to ensure the main thread keeps running
2023-06-16T18:37:29.173+02:00  INFO 6562 --- [inRunController] org.apache.camel.main.MainSupport        : Apache Camel (Main) 4.0.0-SNAPSHOT is starting
2023-06-16T18:37:29.174+02:00  INFO 6562 --- [           main] o.a.c.impl.engine.AbstractCamelContext   : Routes startup (started:8)
2023-06-16T18:37:29.174+02:00  INFO 6562 --- [           main] o.a.c.impl.engine.AbstractCamelContext   :     Started MyCamelRouter (timer://hello)
2023-06-16T18:37:29.174+02:00  INFO 6562 --- [           main] o.a.c.impl.engine.AbstractCamelContext   :     Started timer-route (timer://myTimer)
2023-06-16T18:37:29.174+02:00  INFO 6562 --- [           main] o.a.c.impl.engine.AbstractCamelContext   :     Started route1 (timer://yaml)
2023-06-16T18:37:29.174+02:00  INFO 6562 --- [           main] o.a.c.impl.engine.AbstractCamelContext   :     Started hello (timer://hello)
2023-06-16T18:37:29.174+02:00  INFO 6562 --- [           main] o.a.c.impl.engine.AbstractCamelContext   :     Started route6 (timer://one)
2023-06-16T18:37:29.174+02:00  INFO 6562 --- [           main] o.a.c.impl.engine.AbstractCamelContext   :     Started route7 (timer://deux)
2023-06-16T18:37:29.174+02:00  INFO 6562 --- [           main] o.a.c.impl.engine.AbstractCamelContext   :     Started route8 (timer://one)
2023-06-16T18:37:29.174+02:00  INFO 6562 --- [           main] o.a.c.impl.engine.AbstractCamelContext   :     Started route9 (timer://deux)
2023-06-16T18:37:29.174+02:00  INFO 6562 --- [           main] o.a.c.impl.engine.AbstractCamelContext   : Apache Camel 4.0.0-SNAPSHOT (camel-1) started in 0ms (build:0ms init:0ms start:0ms)
2023-06-16T18:37:29.174+02:00  INFO 6562 --- [           main] c.e.cameldemo.CameldemoApplication       : Started CameldemoApplication in 0.326 seconds (process running for 0.338)

8 routes (a mix of Java, XML, and YAML) started in a little bit more than 300 milliseconds

[davsclaus]

I wonder if the SB aot stuff can be in its own module in core, eg core/camel-spring-boot-aot

[essobedo]

I wonder if the SB aot stuff can be in its own module in core, eg core/camel-spring-boot-aot

Well, it depends on what is your objective behind?

Technically speaking it is of course doable, but in practice, you will need to do the same for each existing starter which means twice more modules to build/publish/test/maintain/release... Moreover, if I did it like this it is because it is how it is done in Spring / Spring Boot, the aot code is a specific package in each module as you can see by yourself for example for spring-beans https://github.com/spring-projects/spring-framework/tree/main/spring-beans/src/main/java/org/springframework/beans/factory/aot

[essobedo]

Related ticket created in Spring spring-projects/spring-framework#30654

[essobedo]

@davsclaus Is it ok as it is, or would you prefer a dedicated module for AOT?

[davsclaus]

Yeah its okay.

However I am just concerned that maintaining this can be causing pain with graalvm changes and mysterious aot issues. The quarkus team have spent endless time with all of this.

And the outcome is that < 1% uses this today.

BTW for XML DSL then use camel-xml-io instead of jaxb based, then its fast and light OOTB and dont need any AOT magic. The JAXB is legacy and hopefully in Camel v5 we can remove JAXB DSLs

[essobedo]

BTW for XML DSL then use camel-xml-io instead of jaxb based, then its fast and light OOTB and dont need any AOT magic. The JAXB is legacy and hopefully in Camel v5 we can remove JAXB DSLs

Oups, good catch, I forgot it, let me retry with camel-xml-io

[davsclaus]

Where you would need jaxb is if you use Spring XML files, eg <beans> which has spring bean stuff as well. If you only have Camel XML routes then xml-io parser is better to use.

[essobedo]

I confirm that it works properly with camel-xml-io, so let's merge it