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The following commit(s) were added to refs/heads/master by this push:
new c38e45c improve bootstrap and configuration documentation
c38e45c is described below
commit c38e45ca0712c697cbc499ae2ad8cc7722429d98
Author: Luca Burgazzoli <lburgazz...@users.noreply.github.com>
AuthorDate: Wed Jul 8 13:49:49 2020 +0200
improve bootstrap and configuration documentation
---
docs/modules/ROOT/pages/user-guide/bootstrap.adoc | 67 +++++++++++++++++++++--
1 file changed, 61 insertions(+), 6 deletions(-)
diff --git a/docs/modules/ROOT/pages/user-guide/bootstrap.adoc
b/docs/modules/ROOT/pages/user-guide/bootstrap.adoc
index 8a49359..241b40b 100644
--- a/docs/modules/ROOT/pages/user-guide/bootstrap.adoc
+++ b/docs/modules/ROOT/pages/user-guide/bootstrap.adoc
@@ -1,12 +1,15 @@
-= Bootstrap Camel Quarkus
+= Bootstrap and configuration
Camel Quarkus automatically configures and deploys a Camel Context bean which
by default is started/stopped according to
the Quarkus Application lifecycle. The configuration step happens at build
time during Quarkus' augmentation phase and
it is driven by the Camel Quarkus extensions which can be tuned using Camel
Quarkus specific `camel.quarkus.*`
properties. After the configuration is done, a minimal Camel Runtime is
assembled and started at
-`https://quarkus.io/guides/writing-extensions#bootstrap-three-phases[RUNTIME_INIT]`
time.
-At that point, any additional configuration should be done using CDI. Below is
an example showing how to configure a
-Camel Component:
+https://quarkus.io/guides/writing-extensions#bootstrap-three-phases[RUNTIME_INIT]
time.
+
+
+== CDI
+
+The https://quarkus.io/guides/cdi-reference[CDI] APIs can be used to configure
various aspects of Camel behavior. For example, to configure the `LogComponent`
you can write a code like:
[source,java]
----
@@ -21,7 +24,7 @@ public class Configurations {
/**
* Produces a {@link LogComponent} instance with a custom exchange
formatter set-up.
*/
- @Named
+ @Named // <1>
LogComponent log() {
DefaultExchangeFormatter formatter = new DefaultExchangeFormatter();
formatter.setShowExchangePattern(false);
@@ -34,12 +37,36 @@ public class Configurations {
}
}
----
+<1> Camel uses the component URI scheme to look-up components from its
registry, this requires you to add the `@Named` annotation to the method,
otherwise the CDI container would create an anonymous bean and Camel would not
be able to look it up.
+
+In Camel Quarkus the Camel components are discovered during the augmentation
phase, producing a new component as shown in the example above would invalidate
any optimization that may have been made.
+
+As a better alternative you can use `@Inject` to obtain an instance of a
component automatically created by Camel or you can observe one of the
https://github.com/apache/camel-quarkus/tree/master/extensions-core/core/runtime/src/main/java/org/apache/camel/quarkus/core/events[events]
fired by Camel Quarkus as shown in the the following example, in which we use
`@Observes` to be notified about components added to the Camel Context:
+
+[source,java]
+----
+import javax.enterprise.context.ApplicationScoped;
+import javax.enterprise.event.Observes;
+import org.apache.camel.quarkus.core.events.ComponentAddEvent;
+import org.apache.camel.component.log.LogComponent;
+
+@ApplicationScoped
+public static class EventHandler {
+ public void onComponentAdd(@Observes ComponentAddEvent event) {
+ if (event.getComponent() instanceof LogComponent) {
+ // do something with the log component
+ }
+ }
+}
+----
+
+== Camel Main
To configure components and other aspects of Apache Camel through properties,
you can add the `camel-quarkus-main`
extension which brings functionalities from
https://camel.apache.org/components/latest/others/main.html[Apache Camel
Main] to Camel Quarkus.
-In the example below, we perform the same configuration of the Log component
via properties like we did above using Java:
+In the example below, we apply the same configuration as the one from the Java
example above by using properties:
[source,properties]
----
@@ -47,3 +74,31 @@ camel.component.log.exchange-formtatter =
#class:org.apache.camel.support.proces
camel.component.log.exchange-formtatter.show-exchange-pattern = false
camel.component.log.exchange-formtatter.show-body-type = false
----
+
+In addition to support configuring Camel through properties,
`camel-quarkus-main` allows you to use conventions to configure the Camel
behavior. For example, if there is a single `ExchangeFormatter` instance in the
CDI container, then it will automatically wire that bean to the `LogComponent`.
+
+Camel Main also brings the option to write
https://quarkus.io/guides/command-mode-reference[Quarkus Command Mode
Applications] with control about when the Camel runtime should start:
+
+[source,java]
+----
+import io.quarkus.runtime.Quarkus;
+import io.quarkus.runtime.annotations.QuarkusMain;
+import org.apache.camel.quarkus.main.CamelMainApplication;
+
+@QuarkusMain
+public class Main {
+ public static void main(String... args) {
+ //
+ // your logic here
+ //
+
+ Quarkus.run(CamelMainApplication.class, args); // <1>
+ }
+}
+----
+<1> Start Quarkus and the Camel Quarkus runtime
+
+[NOTE]
+====
+It is recommended to perform very little logic in the Java Main.
+====
