Merge pull request #600 from gastaldi/extension_config

Migrate extension Config to `@ConfigMapping`

Author: geoand

quarkus-workshop-super-heroes/docs/src/docs/asciidoc/optional-quarkus-extension/quarkus-extension.adoc

@@ -135,10 +135,29 @@ For this, what do we need:
 The _runtime_ part of an extension contains only the classes and resources required at runtime.
 For the version extension, it would be a single class that prints the version.
 
+First, let's create the configuration class that will allow users to dynamically configure whether the version should be printed:
+[example, role="cta"]
+--
+
+Under the `runtime` module, create the `src/main/java` directory, and, in this directory, create a new interface named `io.quarkus.workshop.superheroes.version.runtime.VersionConfig` with the following content:
+
+[source,java]
+----
+include::{code-root}/extension-version/runtime/src/main/java/io/quarkus/workshop/superheroes/version/runtime/VersionConfig.java[]
+----
+--
+The `@ConfigMapping` annotation declares `VersionConfig` as a configuration interface which configuration properties are prefixed with `quarkus.version` prefix. It is also used in CDI aware environments to scan and register Config Mappings.
+
+The `@ConfigRoot` annotation declares that the configuration is available during runtime.
+
+The `@WithDefault("true")` is used to declare the default value returned when `enabled()` is called.
+
+By default, the name of the property is derived from what's declared in the `prefix` attribute inside `@ConfigMapping` plus the name of the method. In our case, the user-configured property will be `quarkus.version.enabled`.
+
 [example, role="cta"]
 --
 
-In the runtime module, create the `src/main/java` directory, and, in this directory, the `io.quarkus.workshop.superheroes.version.runtime.VersionRecorder` class with the following content:
+Still in the `runtime` module, create the `io.quarkus.workshop.superheroes.version.runtime.VersionRecorder` class with the following content:
 
 [source,java]
 ----
@@ -160,27 +179,14 @@ The version extension consists of a single build step that extracts the version
 
 [example, role="cta"]
 --
-First, let's create the configuration class that will allow users to dynamically configure whether the version should be printed:
-
-Under the `deployment` module, create new class `io.quarkus.workshop.superheroes.version.deployment.VersionConfig` with the following content:
-
-[source,java]
-----
-include::{code-root}/extension-version/deployment/src/main/java/io/quarkus/workshop/superheroes/version/deployment/VersionConfig.java[]
-----
---
-
-The `@ConfigRoot` annotation declares `VersionConfig` as a configuration class which configuration properties are prefixed with `quarkus.` prefix.
-
-The `@ConfigItem` is used to declare individual configuration properties. By default, the name of the property is derived from the name of the field. In our case, the user-configured property will be `quarkus.version.enabled`.
 
 Next, open the `ExtensionVersionProcessor` class, and update the content to be:
 
 [source, java]
 ----
 include::{code-root}/extension-version/deployment/src/main/java/io/quarkus/workshop/superheroes/version/deployment/ExtensionVersionProcessor.java[]
 ----
-
+--
 This class is the core of the extension.
 It contains a set of methods annotated with `@BuildStep`.
 

quarkus-workshop-super-heroes/super-heroes/extension-version/deployment/pom.xml

@@ -37,9 +37,6 @@
               <version>${quarkus.version}</version>
             </path>
           </annotationProcessorPaths>
-          <compilerArgs>
-            <arg>-AlegacyConfigRoot=true</arg>
-          </compilerArgs>
         </configuration>
       </plugin>
     </plugins>

quarkus-workshop-super-heroes/super-heroes/extension-version/deployment/src/main/java/io/quarkus/workshop/superheroes/version/deployment/ExtensionVersionProcessor.java

@@ -5,6 +5,7 @@
 import io.quarkus.deployment.annotations.Record;
 import io.quarkus.deployment.builditem.ApplicationInfoBuildItem;
 import io.quarkus.deployment.builditem.FeatureBuildItem;
+import io.quarkus.workshop.superheroes.version.runtime.VersionConfig;
 import io.quarkus.workshop.superheroes.version.runtime.VersionRecorder;
 
 class ExtensionVersionProcessor {
@@ -19,8 +20,6 @@ FeatureBuildItem feature() {
     @BuildStep
     @Record(ExecutionTime.RUNTIME_INIT)
     void recordVersion(ApplicationInfoBuildItem app, VersionConfig versionConfig, VersionRecorder recorder) {
-        if (versionConfig.enabled) {
-            recorder.printVersion(app.getVersion());
-        }
+        recorder.printVersion(versionConfig, app.getVersion());
     }
 }

quarkus-workshop-super-heroes/super-heroes/extension-version/deployment/src/main/java/io/quarkus/workshop/superheroes/version/deployment/VersionConfig.java

@@ -0,0 +1,17 @@
+package io.quarkus.workshop.superheroes.version.runtime;
+
+import io.quarkus.runtime.annotations.ConfigPhase;
+import io.quarkus.runtime.annotations.ConfigRoot;
+import io.smallrye.config.ConfigMapping;
+import io.smallrye.config.WithDefault;
+
+@ConfigMapping(prefix = "quarkus.version")
+@ConfigRoot(phase = ConfigPhase.RUN_TIME)
+public interface VersionConfig {
+
+    /**
+     * Enables or disables the version printing at startup.
+     */
+    @WithDefault("true")
+    boolean enabled();
+}

quarkus-workshop-super-heroes/super-heroes/extension-version/runtime/src/main/java/io/quarkus/workshop/superheroes/version/runtime/VersionConfig.java

@@ -6,8 +6,10 @@
 @Recorder
 public class VersionRecorder {
 
-    public void printVersion(String version) {
-        Logger.getLogger(VersionRecorder.class.getName()).infof("Version: %s", version);
+    public void printVersion(VersionConfig versionConfig, String version) {
+        if (versionConfig.enabled()) {
+            Logger.getLogger(VersionRecorder.class.getName()).infof("Version: %s", version);
+        }
     }
 
 }