Access to workflow/activity instance from context (temporalio#2384)

temporal-sdk/src/main/java/io/temporal/activity/ActivityExecutionContext.java

@@ -147,4 +147,7 @@ public interface ActivityExecutionContext {
    * an activity.
    */
   WorkflowClient getWorkflowClient();
+
+  /** Get the currently running activity instance. */
+  Object getInstance();
 }

temporal-sdk/src/main/java/io/temporal/common/interceptors/ActivityExecutionContextBase.java

@@ -91,4 +91,9 @@ public Scope getMetricsScope() {
   public WorkflowClient getWorkflowClient() {
     return next.getWorkflowClient();
   }
+
+  @Override
+  public Object getInstance() {
+    return next.getInstance();
+  }
 }

temporal-sdk/src/main/java/io/temporal/internal/activity/ActivityExecutionContextFactory.java

@@ -23,5 +23,6 @@
 import com.uber.m3.tally.Scope;
 
 public interface ActivityExecutionContextFactory {
-  InternalActivityExecutionContext createContext(ActivityInfoInternal info, Scope metricsScope);
+  InternalActivityExecutionContext createContext(
+      ActivityInfoInternal info, Object activity, Scope metricsScope);
 }

temporal-sdk/src/main/java/io/temporal/internal/activity/ActivityExecutionContextFactoryImpl.java

@@ -61,10 +61,11 @@ public ActivityExecutionContextFactoryImpl(
 
   @Override
   public InternalActivityExecutionContext createContext(
-      ActivityInfoInternal info, Scope metricsScope) {
+      ActivityInfoInternal info, Object activity, Scope metricsScope) {
     return new ActivityExecutionContextImpl(
         client,
         namespace,
+        activity,
         info,
         dataConverter,
         heartbeatExecutor,

temporal-sdk/src/main/java/io/temporal/internal/activity/ActivityExecutionContextImpl.java

@@ -48,6 +48,7 @@
 class ActivityExecutionContextImpl implements InternalActivityExecutionContext {
   private final Lock lock = new ReentrantLock();
   private final WorkflowClient client;
+  private final Object activity;
   private final ManualActivityCompletionClientFactory manualCompletionClientFactory;
   private final Functions.Proc completionHandle;
   private final HeartbeatContext heartbeatContext;
@@ -61,6 +62,7 @@ class ActivityExecutionContextImpl implements InternalActivityExecutionContext {
   ActivityExecutionContextImpl(
       WorkflowClient client,
       String namespace,
+      Object activity,
       ActivityInfo info,
       DataConverter dataConverter,
       ScheduledExecutorService heartbeatExecutor,
@@ -71,6 +73,7 @@ class ActivityExecutionContextImpl implements InternalActivityExecutionContext {
       Duration maxHeartbeatThrottleInterval,
       Duration defaultHeartbeatThrottleInterval) {
     this.client = client;
+    this.activity = activity;
     this.metricsScope = metricsScope;
     this.info = info;
     this.completionHandle = completionHandle;
@@ -177,4 +180,9 @@ public Object getLastHeartbeatValue() {
   public WorkflowClient getWorkflowClient() {
     return client;
   }
+
+  @Override
+  public Object getInstance() {
+    return activity;
+  }
 }

temporal-sdk/src/main/java/io/temporal/internal/activity/ActivityTaskExecutors.java

@@ -76,7 +76,7 @@ public BaseActivityTaskExecutor(
     @Override
     public ActivityTaskHandler.Result execute(ActivityInfoInternal info, Scope metricsScope) {
       InternalActivityExecutionContext context =
-          executionContextFactory.createContext(info, metricsScope);
+          executionContextFactory.createContext(info, getActivity(), metricsScope);
       ActivityInfo activityInfo = context.getInfo();
       ActivitySerializationContext serializationContext =
           new ActivitySerializationContext(
@@ -144,6 +144,8 @@ public ActivityTaskHandler.Result execute(ActivityInfoInternal info, Scope metri
 
     abstract ActivityInboundCallsInterceptor createRootInboundInterceptor();
 
+    abstract Object getActivity();
+
     abstract Object[] provideArgs(
         Optional<Payloads> input, DataConverter dataConverterWithActivityContext);
 
@@ -203,6 +205,11 @@ ActivityInboundCallsInterceptor createRootInboundInterceptor() {
           activity, method);
     }
 
+    @Override
+    Object getActivity() {
+      return activity;
+    }
+
     @Override
     Object[] provideArgs(Optional<Payloads> input, DataConverter dataConverterWithActivityContext) {
       return dataConverterWithActivityContext.fromPayloads(
@@ -241,6 +248,11 @@ ActivityInboundCallsInterceptor createRootInboundInterceptor() {
           activity);
     }
 
+    @Override
+    Object getActivity() {
+      return activity;
+    }
+
     @Override
     Object[] provideArgs(Optional<Payloads> input, DataConverter dataConverterWithActivityContext) {
       EncodedValues encodedValues = new EncodedValues(input, dataConverterWithActivityContext);

temporal-sdk/src/main/java/io/temporal/internal/activity/LocalActivityExecutionContextFactoryImpl.java

@@ -32,7 +32,7 @@ public LocalActivityExecutionContextFactoryImpl(WorkflowClient client) {
 
   @Override
   public InternalActivityExecutionContext createContext(
-      ActivityInfoInternal info, Scope metricsScope) {
-    return new LocalActivityExecutionContextImpl(client, info, metricsScope);
+      ActivityInfoInternal info, Object activity, Scope metricsScope) {
+    return new LocalActivityExecutionContextImpl(client, activity, info, metricsScope);
   }
 }

temporal-sdk/src/main/java/io/temporal/internal/activity/LocalActivityExecutionContextImpl.java

@@ -30,11 +30,14 @@
 
 class LocalActivityExecutionContextImpl implements InternalActivityExecutionContext {
   private final WorkflowClient client;
+  private final Object activity;
   private final ActivityInfo info;
   private final Scope metricsScope;
 
-  LocalActivityExecutionContextImpl(WorkflowClient client, ActivityInfo info, Scope metricsScope) {
+  LocalActivityExecutionContextImpl(
+      WorkflowClient client, Object activity, ActivityInfo info, Scope metricsScope) {
     this.client = client;
+    this.activity = activity;
     this.info = info;
     this.metricsScope = metricsScope;
   }
@@ -100,4 +103,9 @@ public Object getLastHeartbeatValue() {
   public WorkflowClient getWorkflowClient() {
     return client;
   }
+
+  @Override
+  public Object getInstance() {
+    return activity;
+  }
 }

temporal-sdk/src/main/java/io/temporal/internal/sync/DynamicSyncWorkflowDefinition.java

@@ -30,11 +30,14 @@
 import io.temporal.common.interceptors.WorkflowOutboundCallsInterceptor;
 import io.temporal.workflow.DynamicWorkflow;
 import io.temporal.workflow.Functions;
+import java.util.Objects;
 import java.util.Optional;
+import javax.annotation.Nullable;
 
 final class DynamicSyncWorkflowDefinition implements SyncWorkflowDefinition {
 
   private final Functions.Func1<EncodedValues, ? extends DynamicWorkflow> factory;
+  private RootWorkflowInboundCallsInterceptor rootWorkflowInvoker;
   private final WorkerInterceptor[] workerInterceptors;
   // don't pass it down to other classes, it's a "cached" instance for internal usage only
   private final DataConverter dataConverterWithWorkflowContext;
@@ -52,7 +55,9 @@ public DynamicSyncWorkflowDefinition(
   @Override
   public void initialize(Optional<Payloads> input) {
     SyncWorkflowContext workflowContext = WorkflowInternal.getRootWorkflowContext();
-    workflowInvoker = new RootWorkflowInboundCallsInterceptor(workflowContext, input);
+    RootWorkflowInboundCallsInterceptor rootWorkflowInvoker =
+        new RootWorkflowInboundCallsInterceptor(workflowContext, input);
+    workflowInvoker = rootWorkflowInvoker;
     for (WorkerInterceptor workerInterceptor : workerInterceptors) {
       workflowInvoker = workerInterceptor.interceptWorkflow(workflowInvoker);
     }
@@ -69,6 +74,13 @@ public Optional<Payloads> execute(Header header, Optional<Payloads> input) {
     return dataConverterWithWorkflowContext.toPayloads(result.getResult());
   }
 
+  @Nullable
+  @Override
+  public Object getInstance() {
+    Objects.requireNonNull(rootWorkflowInvoker, "getInstance called before initialize.");
+    return rootWorkflowInvoker.getInstance();
+  }
+
   class RootWorkflowInboundCallsInterceptor extends BaseRootWorkflowInboundCallsInterceptor {
     private DynamicWorkflow workflow;
     private Optional<Payloads> input;
@@ -79,6 +91,10 @@ public RootWorkflowInboundCallsInterceptor(
       this.input = input;
     }
 
+    public DynamicWorkflow getInstance() {
+      return workflow;
+    }
+
     @Override
     public void init(WorkflowOutboundCallsInterceptor outboundCalls) {
       super.init(outboundCalls);

temporal-sdk/src/main/java/io/temporal/internal/sync/POJOWorkflowImplementationFactory.java

@@ -60,6 +60,7 @@
 import java.util.Objects;
 import java.util.Optional;
 import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -315,6 +316,7 @@ private class POJOWorkflowImplementation implements SyncWorkflowDefinition {
     private final Class<?> workflowImplementationClass;
     private final Method workflowMethod;
     private final Constructor<?> ctor;
+    private RootWorkflowInboundCallsInterceptor rootWorkflowInvoker;
     private WorkflowInboundCallsInterceptor workflowInvoker;
     // don't pass it down to other classes, it's a "cached" instance for internal usage only
     private final DataConverter dataConverterWithWorkflowContext;
@@ -333,7 +335,8 @@ public POJOWorkflowImplementation(
     @Override
     public void initialize(Optional<Payloads> input) {
       SyncWorkflowContext workflowContext = WorkflowInternal.getRootWorkflowContext();
-      workflowInvoker = new RootWorkflowInboundCallsInterceptor(workflowContext, input);
+      rootWorkflowInvoker = new RootWorkflowInboundCallsInterceptor(workflowContext, input);
+      workflowInvoker = rootWorkflowInvoker;
       for (WorkerInterceptor workerInterceptor : workerInterceptors) {
         workflowInvoker = workerInterceptor.interceptWorkflow(workflowInvoker);
       }
@@ -357,6 +360,13 @@ public Optional<Payloads> execute(Header header, Optional<Payloads> input)
       return dataConverterWithWorkflowContext.toPayloads(result.getResult());
     }
 
+    @Nullable
+    @Override
+    public Object getInstance() {
+      Objects.requireNonNull(rootWorkflowInvoker, "getInstance called before initialize.");
+      return rootWorkflowInvoker.getInstance();
+    }
+
     private class RootWorkflowInboundCallsInterceptor
         extends BaseRootWorkflowInboundCallsInterceptor {
       private Object workflow;
@@ -368,6 +378,10 @@ public RootWorkflowInboundCallsInterceptor(
         this.input = input;
       }
 
+      public Object getInstance() {
+        return workflow;
+      }
+
       @Override
       public void init(WorkflowOutboundCallsInterceptor outboundCalls) {
         super.init(outboundCalls);

temporal-sdk/src/main/java/io/temporal/internal/sync/SyncWorkflow.java

@@ -101,6 +101,7 @@ public SyncWorkflow(
         new SyncWorkflowContext(
             namespace,
             workflowExecution,
+            workflow,
             signalDispatcher,
             queryDispatcher,
             updateDispatcher,

temporal-sdk/src/main/java/io/temporal/internal/sync/SyncWorkflowContext.java

@@ -101,6 +101,7 @@ final class SyncWorkflowContext implements WorkflowContext, WorkflowOutboundCall
 
   private final String namespace;
   private final WorkflowExecution workflowExecution;
+  private final SyncWorkflowDefinition workflowDefinition;
   private final WorkflowImplementationOptions workflowImplementationOptions;
   private final DataConverter dataConverter;
   // to be used in this class, should not be passed down. Pass the original #dataConverter instead
@@ -125,15 +126,16 @@ final class SyncWorkflowContext implements WorkflowContext, WorkflowOutboundCall
   private Map<String, NexusServiceOptions> nexusServiceOptionsMap;
   private boolean readOnly = false;
   private final WorkflowThreadLocal<UpdateInfo> currentUpdateInfo = new WorkflowThreadLocal<>();
-  // Map of all running update handlers. Key is the update Id of the update request.
+  // Map of all running update handlers. Key is the update ID of the update request.
   private Map<String, UpdateHandlerInfo> runningUpdateHandlers = new HashMap<>();
-  // Map of all running signal handlers. Key is the event Id of the signal event.
+  // Map of all running signal handlers. Key is the event ID of the signal event.
   private Map<Long, SignalHandlerInfo> runningSignalHandlers = new HashMap<>();
   @Nullable private String currentDetails;
 
   public SyncWorkflowContext(
       @Nonnull String namespace,
       @Nonnull WorkflowExecution workflowExecution,
+      @Nullable SyncWorkflowDefinition workflowDefinition,
       SignalDispatcher signalDispatcher,
       QueryDispatcher queryDispatcher,
       UpdateDispatcher updateDispatcher,
@@ -142,6 +144,7 @@ public SyncWorkflowContext(
       List<ContextPropagator> contextPropagators) {
     this.namespace = namespace;
     this.workflowExecution = workflowExecution;
+    this.workflowDefinition = workflowDefinition;
     this.dataConverter = dataConverter;
     this.dataConverterWithCurrentWorkflowContext =
         dataConverter.withContext(
@@ -1492,6 +1495,11 @@ public void setCurrentDetails(String details) {
     currentDetails = details;
   }
 
+  @Nullable
+  public Object getInstance() {
+    return workflowDefinition.getInstance();
+  }
+
   @Nullable
   public String getCurrentDetails() {
     return currentDetails;

temporal-sdk/src/main/java/io/temporal/internal/sync/SyncWorkflowDefinition.java

@@ -23,12 +23,20 @@
 import io.temporal.api.common.v1.Payloads;
 import io.temporal.common.interceptors.Header;
 import java.util.Optional;
+import javax.annotation.Nullable;
 
 /** Workflow wrapper used by the workflow thread to start a workflow */
 interface SyncWorkflowDefinition {
 
   /** Always called first. */
   void initialize(Optional<Payloads> input);
 
+  /**
+   * Returns the workflow instance that is executing this code. Must be called after {@link
+   * #initialize(Optional)}.
+   */
+  @Nullable
+  Object getInstance();
+
   Optional<Payloads> execute(Header header, Optional<Payloads> input);
 }

temporal-sdk/src/main/java/io/temporal/internal/sync/WorkflowInternal.java

@@ -837,6 +837,11 @@ public static String getCurrentDetails() {
     return getRootWorkflowContext().getCurrentDetails();
   }
 
+  @Nullable
+  public static Object getInstance() {
+    return getRootWorkflowContext().getInstance();
+  }
+
   static WorkflowOutboundCallsInterceptor getWorkflowOutboundInterceptor() {
     return getRootWorkflowContext().getWorkflowOutboundInterceptor();
   }

temporal-sdk/src/main/java/io/temporal/workflow/Workflow.java

@@ -29,6 +29,7 @@
 import io.temporal.common.SearchAttributeUpdate;
 import io.temporal.common.SearchAttributes;
 import io.temporal.common.converter.DataConverter;
+import io.temporal.common.interceptors.WorkflowOutboundCallsInterceptor;
 import io.temporal.failure.ActivityFailure;
 import io.temporal.failure.CanceledFailure;
 import io.temporal.failure.ChildWorkflowFailure;
@@ -1385,6 +1386,20 @@ public static String getCurrentDetails() {
     return WorkflowInternal.getCurrentDetails();
   }
 
+  /**
+   * Get the currently running workflow instance.
+   *
+   * @apiNote The instance is only available after it has been initialized. This function will
+   *     return null if called before the workflow has been initialized. For example, this could
+   *     happen if the function is called from a {@link WorkflowInit} constructor or {@link
+   *     io.temporal.common.interceptors.WorkflowInboundCallsInterceptor#init(WorkflowOutboundCallsInterceptor)}.
+   */
+  @Experimental
+  @Nullable
+  public static Object getInstance() {
+    return WorkflowInternal.getInstance();
+  }
+
   /** Prohibit instantiation. */
   private Workflow() {}
 }