refactor: return DependentResource.desired now returns Optional

Author: metacosm

operator-framework-core/src/main/java/io/javaoperatorsdk/operator/api/reconciler/dependent/DependentResource.java

@@ -1,5 +1,7 @@
 package io.javaoperatorsdk.operator.api.reconciler.dependent;
 
+import java.util.Optional;
+
 import io.fabric8.kubernetes.api.model.HasMetadata;
 import io.javaoperatorsdk.operator.api.config.Utils;
 import io.javaoperatorsdk.operator.api.reconciler.Context;
@@ -19,23 +21,21 @@ default Class<R> resourceType() {
   default void delete(R fetched, P primary, Context context) {}
 
   /**
-   * todo: return Optional<R></R> instead?
-   * 
    * Computes the desired state of the dependent based on the state provided by the specified
    * primary resource.
    * 
-   * The default implementation returns {@code null} which corresponds to the case where the
+   * The default implementation returns {@code empty} which corresponds to the case where the
    * associated dependent should never be created by the associated reconciler or that the global
    * state of the cluster doesn't allow for the resource to be created at this point.
    * 
    * @param primary the primary resource associated with the reconciliation process
    * @param context the {@link Context} associated with the reconciliation process
    * @return an instance of the dependent resource matching the desired state specified by the
-   *         primary resource or {@code null} if the dependent shouldn't be created at this point
+   *         primary resource or {@code empty} if the dependent shouldn't be created at this point
    *         (or ever)
    */
-  default R desired(P primary, Context context) {
-    return null;
+  default Optional<R> desired(P primary, Context context) {
+    return Optional.empty();
   }
 
   /**

operator-framework-core/src/main/java/io/javaoperatorsdk/operator/processing/dependent/DependentResourceController.java

@@ -1,5 +1,7 @@
 package io.javaoperatorsdk.operator.processing.dependent;
 
+import java.util.Optional;
+
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -40,7 +42,7 @@ public boolean match(R actual, P primary, Context context) {
   }
 
   @Override
-  public R desired(P primary, Context context) {
+  public Optional<R> desired(P primary, Context context) {
     return delegate.desired(primary, context);
   }
 
@@ -91,9 +93,7 @@ public UpdateControl<P> reconcile(P resource, Context context) {
     var actual = getFor(resource, context);
     if (actual == null || !match(actual, resource, context)) {
       final var desired = desired(resource, context);
-      if (desired != null) {
-        createOrReplaceDependent(resource, desired, context);
-      }
+      desired.ifPresent(d -> createOrReplaceDependent(resource, d, context));
     }
     return UpdateControl.noUpdate();
   }

sample-operators/mysql-schema/src/main/java/io/javaoperatorsdk/operator/sample/MySQLSchemaReconciler.java

@@ -57,8 +57,8 @@ private static String encode(String value) {
     }
 
     @Override
-    public Secret desired(MySQLSchema schema, Context context) {
-      return new SecretBuilder()
+    public Optional<Secret> desired(MySQLSchema schema, Context context) {
+      return Optional.of(new SecretBuilder()
           .withNewMetadata()
           .withName(context.getMandatory(MYSQL_SECRET_NAME, String.class))
           .withNamespace(schema.getMetadata().getNamespace())
@@ -67,10 +67,11 @@ public Secret desired(MySQLSchema schema, Context context) {
               context.getMandatory(MYSQL_SECRET_USERNAME, String.class)))
           .addToData("MYSQL_PASSWORD", encode(
               context.getMandatory(MYSQL_SECRET_PASSWORD, String.class)))
-          .build();
+          .build());
     }
   }
 
+  @SuppressWarnings("rawtypes")
   @Override
   public void injectInto(EventSourceContext context) {
     context.put(MYSQL_DB_CONFIG, mysqlDbConfig);

sample-operators/mysql-schema/src/main/java/io/javaoperatorsdk/operator/sample/SchemaDependentResource.java

@@ -3,6 +3,7 @@
 import java.sql.Connection;
 import java.sql.DriverManager;
 import java.sql.SQLException;
+import java.util.Optional;
 
 import io.javaoperatorsdk.operator.api.reconciler.Context;
 import io.javaoperatorsdk.operator.api.reconciler.EventSourceContext;
@@ -30,7 +31,7 @@ public EventSource initEventSource(EventSourceContext<MySQLSchema> context) {
   }
 
   @Override
-  public Schema desired(MySQLSchema primary, Context context) {
+  public Optional<Schema> desired(MySQLSchema primary, Context context) {
     try (Connection connection = getConnection()) {
       final var schema = SchemaService.createSchemaAndRelatedUser(
           connection,
@@ -41,7 +42,7 @@ public Schema desired(MySQLSchema primary, Context context) {
 
       // put the newly built schema in the context to let the reconciler know we just built it
       context.put(MySQLSchemaReconciler.BUILT_SCHEMA, schema);
-      return schema;
+      return Optional.of(schema);
     } catch (SQLException e) {
       MySQLSchemaReconciler.log.error("Error while creating Schema", e);
       throw new IllegalStateException(e);

sample-operators/tomcat-operator/src/main/java/io/javaoperatorsdk/operator/sample/DeploymentDependentResource.java

@@ -1,5 +1,7 @@
 package io.javaoperatorsdk.operator.sample;
 
+import java.util.Optional;
+
 import io.fabric8.kubernetes.api.model.ObjectMeta;
 import io.fabric8.kubernetes.api.model.apps.Deployment;
 import io.fabric8.kubernetes.api.model.apps.DeploymentBuilder;
@@ -12,7 +14,7 @@ public class DeploymentDependentResource
     implements DependentResource<Deployment, Tomcat> {
 
   @Override
-  public Deployment desired(Tomcat tomcat, Context context) {
+  public Optional<Deployment> desired(Tomcat tomcat, Context context) {
     Deployment deployment = TomcatReconciler.loadYaml(Deployment.class, "deployment.yaml");
     final ObjectMeta tomcatMetadata = tomcat.getMetadata();
     final String tomcatName = tomcatMetadata.getName();
@@ -37,7 +39,7 @@ public Deployment desired(Tomcat tomcat, Context context) {
         .endTemplate()
         .endSpec()
         .build();
-    return deployment;
+    return Optional.of(deployment);
   }
 
   private String tomcatImage(Tomcat tomcat) {

sample-operators/tomcat-operator/src/main/java/io/javaoperatorsdk/operator/sample/ServiceDependentResource.java

@@ -1,5 +1,7 @@
 package io.javaoperatorsdk.operator.sample;
 
+import java.util.Optional;
+
 import io.fabric8.kubernetes.api.model.ObjectMeta;
 import io.fabric8.kubernetes.api.model.Service;
 import io.fabric8.kubernetes.api.model.ServiceBuilder;
@@ -9,16 +11,16 @@
 public class ServiceDependentResource implements DependentResource<Service, Tomcat> {
 
   @Override
-  public Service desired(Tomcat tomcat, Context context) {
+  public Optional<Service> desired(Tomcat tomcat, Context context) {
     final ObjectMeta tomcatMetadata = tomcat.getMetadata();
-    return new ServiceBuilder(TomcatReconciler.loadYaml(Service.class, "service.yaml"))
+    return Optional.of(new ServiceBuilder(TomcatReconciler.loadYaml(Service.class, "service.yaml"))
         .editMetadata()
         .withName(tomcatMetadata.getName())
         .withNamespace(tomcatMetadata.getNamespace())
         .endMetadata()
         .editSpec()
         .addToSelector("app", tomcatMetadata.getName())
         .endSpec()
-        .build();
+        .build());
   }
 }