providing an option for the plugins to use Spring DI

Signed-off-by: Santhosh Gandhe <[email protected]>

data-prepper-api/src/main/java/org/opensearch/dataprepper/model/annotations/DataPrepperPlugin.java

@@ -72,4 +72,16 @@
      * @since 1.2
      */
     Class<?> pluginConfigurationType() default PluginSetting.class;
+
+    /**
+     * Optional Packages to scan for Data Prepper DI components.
+     * Plugins provide this list if they want to use Dependency Injection in its module.
+     * Providing this value, implicitly assumes and initiates plugin specific isolated ApplictionContext.
+     * <p>
+     * The package names that spring context scans will be picked up by these marker classes.
+     *
+     * @return Array of packages to scan
+     * @since 2.2
+     */
+    Class[] packagesToScanForDI() default {};
 }

data-prepper-plugin-framework/src/main/java/org/opensearch/dataprepper/plugin/DefaultPluginFactory.java

@@ -13,6 +13,7 @@
 import org.opensearch.dataprepper.model.sink.SinkContext;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
+import org.springframework.beans.factory.BeanFactory;
 import org.springframework.context.annotation.DependsOn;
 
 import javax.inject.Inject;
@@ -115,13 +116,15 @@ private <T> ComponentPluginArgumentsContext getConstructionContext(final PluginS
         final PluginConfigObservable pluginConfigObservable = pluginConfigurationObservableFactory
                 .createDefaultPluginConfigObservable(pluginConfigurationConverter, pluginConfigurationType, pluginSetting);
 
+        BeanFactory beanFactory =
+                pluginBeanFactoryProvider.initializePluginSpecificIsolatedContextCombinedWithShared(pluginAnnotation);
         return new ComponentPluginArgumentsContext.Builder()
                 .withPluginSetting(pluginSetting)
                 .withPipelineDescription(pluginSetting)
                 .withPluginConfiguration(configuration)
                 .withPluginFactory(this)
                 .withSinkContext(sinkContext)
-                .withBeanFactory(pluginBeanFactoryProvider.get())
+                .withBeanFactory(beanFactory)
                 .withPluginConfigurationObservable(pluginConfigObservable)
                 .withTypeArgumentSuppliers(applicationContextToTypedSuppliers.getArgumentsSuppliers())
                 .build();

data-prepper-plugin-framework/src/main/java/org/opensearch/dataprepper/plugin/PluginBeanFactoryProvider.java

@@ -5,13 +5,15 @@
 
 package org.opensearch.dataprepper.plugin;
 
+import org.opensearch.dataprepper.model.annotations.DataPrepperPlugin;
 import org.springframework.beans.factory.BeanFactory;
 import org.springframework.context.ApplicationContext;
+import org.springframework.context.annotation.AnnotationConfigApplicationContext;
 import org.springframework.context.support.GenericApplicationContext;
 
 import javax.inject.Inject;
 import javax.inject.Named;
-import javax.inject.Provider;
+import java.util.Arrays;
 import java.util.Objects;
 
 /**
@@ -25,7 +27,7 @@
  * <p><i>publicContext</i> is the root {@link ApplicationContext}</p>
  */
 @Named
-class PluginBeanFactoryProvider implements Provider<BeanFactory> {
+class PluginBeanFactoryProvider {
     private final GenericApplicationContext sharedPluginApplicationContext;
     private final GenericApplicationContext coreApplicationContext;
 
@@ -57,8 +59,17 @@ GenericApplicationContext getCoreApplicationContext() {
      * instead, a new isolated {@link ApplicationContext} should be created.
      * @return BeanFactory A BeanFactory that inherits from {@link PluginBeanFactoryProvider#sharedPluginApplicationContext}
      */
-    public BeanFactory get() {
-        final GenericApplicationContext isolatedPluginApplicationContext = new GenericApplicationContext(sharedPluginApplicationContext);
-        return isolatedPluginApplicationContext.getBeanFactory();
+    public BeanFactory initializePluginSpecificIsolatedContextCombinedWithShared(DataPrepperPlugin pluginAnnotation) {
+        AnnotationConfigApplicationContext pluginDIContext = new AnnotationConfigApplicationContext();
+        if(pluginAnnotation.packagesToScanForDI().length>0) {
+            // If packages to scan is provided in this plugin annotation, which indicates
+            // that this plugin is interested in using Dependency Injection isolated for its module
+            Arrays.stream(pluginAnnotation.packagesToScanForDI())
+                    .map(Class::getPackageName)
+                    .forEach(pluginDIContext::scan);
+            pluginDIContext.refresh();
+        }
+        pluginDIContext.setParent(sharedPluginApplicationContext);
+        return pluginDIContext.getBeanFactory();
     }
 }