Plugin Support for Java SDK

temporal-sdk/src/main/java/io/temporal/client/WorkflowClientInternalImpl.java

@@ -24,6 +24,7 @@
 import io.temporal.internal.sync.StubMarker;
 import io.temporal.serviceclient.MetricsTag;
 import io.temporal.serviceclient.WorkflowServiceStubs;
+import io.temporal.serviceclient.WorkflowServiceStubsPlugin;
 import io.temporal.worker.WorkerFactory;
 import io.temporal.workflow.*;
 import java.lang.annotation.Annotation;
@@ -36,9 +37,13 @@
 import java.util.stream.StreamSupport;
 import javax.annotation.Nonnull;
 import javax.annotation.Nullable;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 final class WorkflowClientInternalImpl implements WorkflowClient, WorkflowClientInternal {
 
+  private static final Logger log = LoggerFactory.getLogger(WorkflowClientInternalImpl.class);
+
   private final GenericWorkflowClient genericClient;
   private final WorkflowClientOptions options;
   private final ManualActivityCompletionClientFactory manualActivityCompletionClientFactory;
@@ -65,7 +70,22 @@ public static WorkflowClient newInstance(
 
   WorkflowClientInternalImpl(
       WorkflowServiceStubs workflowServiceStubs, WorkflowClientOptions options) {
-    options = WorkflowClientOptions.newBuilder(options).validateAndBuildWithDefaults();
+    // Extract WorkflowClientPlugins from service stubs plugins (propagation)
+    WorkflowClientPlugin[] propagatedPlugins =
+        extractClientPlugins(workflowServiceStubs.getOptions().getPlugins());
+
+    // Merge propagated plugins with client-specified plugins
+    WorkflowClientPlugin[] mergedPlugins = mergePlugins(propagatedPlugins, options.getPlugins());
+
+    // Apply plugin configuration phase (forward order) on user-provided options,
+    // so plugins see unmodified state before defaults and plugin merging
+    WorkflowClientOptions.Builder builder = WorkflowClientOptions.newBuilder(options);
+    for (WorkflowClientPlugin plugin : mergedPlugins) {
+      plugin.configureWorkflowClient(builder);
+    }
+    // Set merged plugins after configuration, then validate
+    builder.setPlugins(mergedPlugins);
+    options = builder.validateAndBuildWithDefaults();
     workflowServiceStubs =
         new NamespaceInjectWorkflowServiceStubs(workflowServiceStubs, options.getNamespace());
     this.options = options;
@@ -771,4 +791,56 @@ public NexusStartWorkflowResponse startNexus(
       WorkflowInvocationHandler.closeAsyncInvocation();
     }
   }
+
+  /**
+   * Extracts WorkflowClientPlugins from service stubs plugins. Only plugins that also implement
+   * {@link WorkflowClientPlugin} are included. This enables plugin propagation from service stubs
+   * to workflow client.
+   */
+  private static WorkflowClientPlugin[] extractClientPlugins(
+      WorkflowServiceStubsPlugin[] stubsPlugins) {
+    if (stubsPlugins == null || stubsPlugins.length == 0) {
+      return new WorkflowClientPlugin[0];
+    }
+    List<WorkflowClientPlugin> clientPlugins = new ArrayList<>();
+    for (WorkflowServiceStubsPlugin plugin : stubsPlugins) {
+      if (plugin instanceof WorkflowClientPlugin) {
+        clientPlugins.add((WorkflowClientPlugin) plugin);
+      }
+    }
+    return clientPlugins.toArray(new WorkflowClientPlugin[0]);
+  }
+
+  /**
+   * Merges propagated plugins with explicitly specified plugins. Propagated plugins come first
+   * (from service stubs), followed by client-specific plugins.
+   */
+  private static WorkflowClientPlugin[] mergePlugins(
+      WorkflowClientPlugin[] propagated, WorkflowClientPlugin[] explicit) {
+    boolean propagatedEmpty = propagated == null || propagated.length == 0;
+    boolean explicitEmpty = explicit == null || explicit.length == 0;
+    if (propagatedEmpty && explicitEmpty) {
+      return new WorkflowClientPlugin[0];
+    }
+    if (propagatedEmpty) {
+      return explicit;
+    }
+    if (explicitEmpty) {
+      return propagated;
+    }
+    // Warn about duplicate plugin instances (same object in both lists)
+    Set<WorkflowClientPlugin> propagatedSet = new HashSet<>(Arrays.asList(propagated));
+    for (WorkflowClientPlugin p : explicit) {
+      if (propagatedSet.contains(p)) {
+        log.warn(
+            "Plugin instance {} is present in both propagated plugins (from service stubs) and "
+                + "explicit plugins. It will run twice which may not be the intended behavior.",
+            p.getName());
+      }
+    }
+    WorkflowClientPlugin[] merged = new WorkflowClientPlugin[propagated.length + explicit.length];
+    System.arraycopy(propagated, 0, merged, 0, propagated.length);
+    System.arraycopy(explicit, 0, merged, propagated.length, explicit.length);
+    return merged;
+  }
 }

temporal-sdk/src/main/java/io/temporal/client/WorkflowClientOptions.java

@@ -1,6 +1,7 @@
 package io.temporal.client;
 
 import io.temporal.api.enums.v1.QueryRejectCondition;
+import io.temporal.common.Experimental;
 import io.temporal.common.context.ContextPropagator;
 import io.temporal.common.converter.DataConverter;
 import io.temporal.common.converter.GlobalDataConverter;
@@ -47,6 +48,7 @@ public static final class Builder {
     private String binaryChecksum;
     private List<ContextPropagator> contextPropagators;
     private QueryRejectCondition queryRejectCondition;
+    private WorkflowClientPlugin[] plugins;
 
     private Builder() {}
 
@@ -61,6 +63,7 @@ private Builder(WorkflowClientOptions options) {
       binaryChecksum = options.binaryChecksum;
       contextPropagators = options.contextPropagators;
       queryRejectCondition = options.queryRejectCondition;
+      plugins = options.plugins;
     }
 
     public Builder setNamespace(String namespace) {
@@ -132,6 +135,24 @@ public Builder setQueryRejectCondition(QueryRejectCondition queryRejectCondition
       return this;
     }
 
+    /**
+     * Sets the workflow client plugins to use with this client. Plugins can modify client
+     * configuration.
+     *
+     * <p>Plugins that also implement {@link io.temporal.worker.WorkerPlugin} are automatically
+     * propagated to workers created from this client.
+     *
+     * @param plugins the workflow client plugins to use
+     * @return this builder for chaining
+     * @see WorkflowClientPlugin
+     * @see io.temporal.worker.WorkerPlugin
+     */
+    @Experimental
+    public Builder setPlugins(WorkflowClientPlugin... plugins) {
+      this.plugins = Objects.requireNonNull(plugins);
+      return this;
+    }
+
     public WorkflowClientOptions build() {
       return new WorkflowClientOptions(
           namespace,
@@ -140,9 +161,21 @@ public WorkflowClientOptions build() {
           identity,
           binaryChecksum,
           contextPropagators,
-          queryRejectCondition);
+          queryRejectCondition,
+          plugins == null ? EMPTY_PLUGINS : plugins);
     }
 
+    /**
+     * Validates options and builds with defaults applied.
+     *
+     * <p>Note: If plugins are configured via {@link #setPlugins(WorkflowClientPlugin...)}, they
+     * will have an opportunity to modify options after this method is called, when the options are
+     * passed to {@link WorkflowClient#newInstance}. This means validation performed here occurs
+     * before plugin modifications. In most cases, users should simply call {@link #build()} and let
+     * the client creation handle validation.
+     *
+     * @return validated options with defaults applied
+     */
     public WorkflowClientOptions validateAndBuildWithDefaults() {
       String name = identity == null ? ManagementFactory.getRuntimeMXBean().getName() : identity;
       return new WorkflowClientOptions(
@@ -154,7 +187,8 @@ public WorkflowClientOptions validateAndBuildWithDefaults() {
           contextPropagators == null ? EMPTY_CONTEXT_PROPAGATORS : contextPropagators,
           queryRejectCondition == null
               ? QueryRejectCondition.QUERY_REJECT_CONDITION_UNSPECIFIED
-              : queryRejectCondition);
+              : queryRejectCondition,
+          plugins == null ? EMPTY_PLUGINS : plugins);
     }
   }
 
@@ -163,6 +197,8 @@ public WorkflowClientOptions validateAndBuildWithDefaults() {
 
   private static final List<ContextPropagator> EMPTY_CONTEXT_PROPAGATORS = Collections.emptyList();
 
+  private static final WorkflowClientPlugin[] EMPTY_PLUGINS = new WorkflowClientPlugin[0];
+
   private final String namespace;
 
   private final DataConverter dataConverter;
@@ -177,21 +213,25 @@ public WorkflowClientOptions validateAndBuildWithDefaults() {
 
   private final QueryRejectCondition queryRejectCondition;
 
+  private final WorkflowClientPlugin[] plugins;
+
   private WorkflowClientOptions(
       String namespace,
       DataConverter dataConverter,
       WorkflowClientInterceptor[] interceptors,
       String identity,
       String binaryChecksum,
       List<ContextPropagator> contextPropagators,
-      QueryRejectCondition queryRejectCondition) {
+      QueryRejectCondition queryRejectCondition,
+      WorkflowClientPlugin[] plugins) {
     this.namespace = namespace;
     this.dataConverter = dataConverter;
     this.interceptors = interceptors;
     this.identity = identity;
     this.binaryChecksum = binaryChecksum;
     this.contextPropagators = contextPropagators;
     this.queryRejectCondition = queryRejectCondition;
+    this.plugins = plugins;
   }
 
   /**
@@ -236,6 +276,19 @@ public QueryRejectCondition getQueryRejectCondition() {
     return queryRejectCondition;
   }
 
+  /**
+   * Returns the workflow client plugins configured for this client.
+   *
+   * <p>Plugins that also implement {@link io.temporal.worker.WorkerPlugin} are automatically
+   * propagated to workers created from this client.
+   *
+   * @return the array of workflow client plugins, never null
+   */
+  @Experimental
+  public WorkflowClientPlugin[] getPlugins() {
+    return plugins;
+  }
+
   @Override
   public String toString() {
     return "WorkflowClientOptions{"
@@ -256,6 +309,8 @@ public String toString() {
         + contextPropagators
         + ", queryRejectCondition="
         + queryRejectCondition
+        + ", plugins="
+        + Arrays.toString(plugins)
         + '}';
   }
 
@@ -270,7 +325,8 @@ public boolean equals(Object o) {
         && com.google.common.base.Objects.equal(identity, that.identity)
         && com.google.common.base.Objects.equal(binaryChecksum, that.binaryChecksum)
         && com.google.common.base.Objects.equal(contextPropagators, that.contextPropagators)
-        && queryRejectCondition == that.queryRejectCondition;
+        && queryRejectCondition == that.queryRejectCondition
+        && Arrays.equals(plugins, that.plugins);
   }
 
   @Override
@@ -282,6 +338,7 @@ public int hashCode() {
         identity,
         binaryChecksum,
         contextPropagators,
-        queryRejectCondition);
+        queryRejectCondition,
+        Arrays.hashCode(plugins));
   }
 }

temporal-sdk/src/main/java/io/temporal/client/WorkflowClientPlugin.java

@@ -0,0 +1,80 @@
+/*
+ * Copyright (C) 2022 Temporal Technologies, Inc. All Rights Reserved.
+ *
+ * Copyright (C) 2012-2016 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ *
+ * Modifications copyright (C) 2017 Uber Technologies, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this material except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package io.temporal.client;
+
+import io.temporal.common.Experimental;
+import io.temporal.common.SimplePlugin;
+import javax.annotation.Nonnull;
+
+/**
+ * Plugin interface for customizing Temporal workflow client configuration.
+ *
+ * <p>This interface is separate from {@link
+ * io.temporal.serviceclient.WorkflowServiceStubs.ServiceStubsPlugin} to allow plugins that only
+ * need to configure the workflow client without affecting the underlying gRPC connection.
+ *
+ * <p>Plugins that implement both {@code ServiceStubsPlugin} and {@code WorkflowClientPlugin} will
+ * have their service stubs configuration applied when creating the service stubs, and their client
+ * configuration applied when creating the workflow client.
+ *
+ * <p>Plugins that also implement {@link io.temporal.worker.WorkerPlugin} are automatically
+ * propagated from the client to workers created from that client.
+ *
+ * <p>Example implementation:
+ *
+ * <pre>{@code
+ * public class LoggingPlugin extends SimplePlugin {
+ *     public LoggingPlugin() {
+ *         super("my-org.logging");
+ *     }
+ *
+ *     @Override
+ *     public void configureClient(WorkflowClientOptions.Builder builder) {
+ *         // Add custom interceptor
+ *         builder.setInterceptors(new LoggingInterceptor());
+ *     }
+ * }
+ * }</pre>
+ *
+ * @see io.temporal.serviceclient.WorkflowServiceStubs.ServiceStubsPlugin
+ * @see io.temporal.worker.WorkerPlugin
+ * @see SimplePlugin
+ */
+@Experimental
+public interface WorkflowClientPlugin {
+
+  /**
+   * Returns a unique name for this plugin. Used for logging and duplicate detection. Recommended
+   * format: "organization.plugin-name" (e.g., "io.temporal.tracing")
+   *
+   * @return fully qualified plugin name
+   */
+  @Nonnull
+  String getName();
+
+  /**
+   * Allows the plugin to modify workflow client options before the client is created. Called during
+   * configuration phase in forward (registration) order.
+   *
+   * @param builder the options builder to modify
+   */
+  void configureWorkflowClient(@Nonnull WorkflowClientOptions.Builder builder);
+}