refactor: migrate to Java ServiceLoader for plugin registration

build.gradle

@@ -47,6 +47,7 @@ dependencies {
     compileOnly "io.micronaut.validation:micronaut-validation"
 
     // kestra
+    annotationProcessor group: "io.kestra", name: "processor", version: kestraVersion
     compileOnly group: "io.kestra", name: "core", version: kestraVersion
 
     // AWS libs: versions are managed by the Micronaut BOM
@@ -104,6 +105,9 @@ dependencies {
     testImplementation "org.testcontainers:testcontainers:1.19.1"
     testImplementation "org.testcontainers:localstack:1.19.6"
     testImplementation "com.amazonaws:aws-java-sdk-s3"
+
+    // test
+    testAnnotationProcessor group: "io.kestra", name: "processor", version: kestraVersion
 }
 
 /**********************************************************************************************************************\

gradle.properties

@@ -1,4 +1,4 @@
 version=0.17.0-SNAPSHOT
-kestraVersion=[0.16,)
+kestraVersion=[0.17,)
 micronautVersion=4.3.7
 lombokVersion=1.18.32

src/main/java/io/kestra/storage/s3/S3Storage.java

@@ -1,5 +1,6 @@
 package io.kestra.storage.s3;
 
+import io.kestra.core.models.annotations.Plugin;
 import io.kestra.core.storages.FileAttributes;
 import io.kestra.core.storages.StorageInterface;
 import io.micronaut.core.annotation.Introspected;
@@ -36,13 +37,23 @@
 @Singleton
 @Introspected
 @S3StorageEnabled
+@Plugin
 public class S3Storage implements StorageInterface {
     private final S3Client s3Client;
 
     private final S3AsyncClient s3AsyncClient;
 
     private final S3Config s3Config;
 
+    /**
+     * No-arg constructor - required for Kestra plugin.
+     */
+    public S3Storage() {
+        this.s3Config = null;
+        this.s3AsyncClient = null;
+        this.s3Client = null;
+    }
+
     public S3Storage(final S3Config s3Config) {
         this.s3Config = s3Config;
         this.s3Client = S3ClientFactory.getS3Client(s3Config);