Trait WorkflowInterceptor 

pub trait WorkflowInterceptor: 'static {
    // Provided methods
    fn initialize_workflow(
        &self,
        _ctx: WorkflowContextView,
        input: InitializeWorkflowInput,
        next: WorkflowNext<'_, InitializeWorkflowInput, InitializeWorkflowOutput>,
    ) -> InitializeWorkflowOutput { ... }
    fn execute<'a>(
        &'a self,
        _ctx: WorkflowInterceptorContext,
        input: ExecuteWorkflowInput,
        next: WorkflowNext<'a, ExecuteWorkflowInput, WorkflowInterceptorFuture<'a, Result<Box<dyn WorkflowOutputValue>, WorkflowTermination>>>,
    ) -> WorkflowInterceptorFuture<'a, Result<Box<dyn WorkflowOutputValue>, WorkflowTermination>>  { ... }
    fn handle_signal<'a>(
        &'a self,
        _ctx: WorkflowInterceptorContext,
        input: HandleSignalInput,
        next: WorkflowNext<'a, HandleSignalInput, WorkflowInterceptorFuture<'a, Result<(), WorkflowError>>>,
    ) -> WorkflowInterceptorFuture<'a, Result<(), WorkflowError>>  { ... }
    fn handle_update<'a>(
        &'a self,
        _ctx: WorkflowInterceptorContext,
        input: HandleUpdateInput,
        next: WorkflowNext<'a, HandleUpdateInput, WorkflowInterceptorFuture<'a, Result<Box<dyn WorkflowOutputValue>, WorkflowError>>>,
    ) -> WorkflowInterceptorFuture<'a, Result<Box<dyn WorkflowOutputValue>, WorkflowError>>  { ... }
    fn handle_query(
        &self,
        _ctx: SyncWorkflowInterceptorContext,
        input: HandleQueryInput,
        next: WorkflowNext<'_, HandleQueryInput, Result<Box<dyn WorkflowOutputValue>, WorkflowError>>,
    ) -> Result<Box<dyn WorkflowOutputValue>, WorkflowError> { ... }
    fn validate_update(
        &self,
        _ctx: SyncWorkflowInterceptorContext,
        input: ValidateUpdateInput,
        next: WorkflowNext<'_, ValidateUpdateInput, Result<(), WorkflowError>>,
    ) -> Result<(), WorkflowError> { ... }
    fn start_timer(
        &self,
        _ctx: WorkflowInterceptorContext,
        input: StartTimerInput,
        next: WorkflowNext<'static, StartTimerInput, CancellableWorkflowOutboundFuture<TimerResult>>,
    ) -> CancellableWorkflowOutboundFuture<TimerResult>  { ... }
    fn schedule_activity(
        &self,
        _ctx: WorkflowInterceptorContext,
        input: ScheduleActivityInput,
        next: WorkflowNext<'static, ScheduleActivityInput, CancellableWorkflowOutboundFuture<Result<Box<dyn WorkflowOutboundValue>, ActivityExecutionError>>>,
    ) -> CancellableWorkflowOutboundFuture<Result<Box<dyn WorkflowOutboundValue>, ActivityExecutionError>>  { ... }
    fn schedule_local_activity(
        &self,
        _ctx: WorkflowInterceptorContext,
        input: ScheduleLocalActivityInput,
        next: WorkflowNext<'static, ScheduleLocalActivityInput, CancellableWorkflowOutboundFuture<Result<Box<dyn WorkflowOutboundValue>, ActivityExecutionError>>>,
    ) -> CancellableWorkflowOutboundFuture<Result<Box<dyn WorkflowOutboundValue>, ActivityExecutionError>>  { ... }
    fn start_child_workflow(
        &self,
        _ctx: WorkflowInterceptorContext,
        input: StartChildWorkflowInput,
        next: WorkflowNext<'static, StartChildWorkflowInput, CancellableWorkflowOutboundFuture<Result<StartChildWorkflowOutput, ChildWorkflowStartError>>>,
    ) -> CancellableWorkflowOutboundFuture<Result<StartChildWorkflowOutput, ChildWorkflowStartError>>  { ... }
    fn signal_workflow(
        &self,
        _ctx: WorkflowInterceptorContext,
        input: SignalWorkflowInput,
        next: WorkflowNext<'static, SignalWorkflowInput, CancellableWorkflowOutboundFuture<Result<(), WorkflowSignalError>>>,
    ) -> CancellableWorkflowOutboundFuture<Result<(), WorkflowSignalError>>  { ... }
    fn cancel_external_workflow(
        &self,
        _ctx: WorkflowInterceptorContext,
        input: CancelExternalWorkflowInput,
        next: WorkflowNext<'static, CancelExternalWorkflowInput, WorkflowOutboundFuture<Result<CancelExternalOk, Failure>>>,
    ) -> WorkflowOutboundFuture<Result<CancelExternalOk, Failure>>  { ... }
    fn continue_as_new(
        &self,
        _ctx: SyncWorkflowInterceptorContext,
        input: ContinueAsNewInput,
        next: WorkflowNext<'static, ContinueAsNewInput, Result<Infallible, WorkflowTermination>>,
    ) -> Result<Infallible, WorkflowTermination> { ... }
    fn start_nexus_operation(
        &self,
        _ctx: WorkflowInterceptorContext,
        input: StartNexusOperationInput,
        next: WorkflowNext<'static, StartNexusOperationInput, CancellableWorkflowOutboundFuture<Result<StartedNexusOperation, Failure>>>,
    ) -> CancellableWorkflowOutboundFuture<Result<StartedNexusOperation, Failure>>  { ... }
}

Interceptor for calls into workflow code and commands issued by workflow code.

Implement this trait for behavior that should wrap workflow operations. Inbound methods intercept operations such as workflow execution and handler dispatch; outbound methods intercept timers, activities, child workflows, external workflow calls, continue-as-new, and Nexus operations.

Implementations normally calls WorkflowNext::run exactly once. It may transform the input first, then inspect or transform the result. Not calling next short-circuits the operation, so it should only be done if intentionally skipping the operation.

The async inbound methods return WorkflowInterceptorFuture. Use WorkflowInterceptorFuture::new to wrap an async block around the downstream future: call next.run(input).await to call the next interceptor. See the module-level guide for a complete example and the determinism requirements.

Interceptors run as workflow code and are recreated when an evicted workflow is rebuilt. Their behavior and any instance-local state must remain deterministic under replay. Async methods may await only workflow scheduler primitives or SDK-provided workflow futures.

A WorkflowInterceptorConstructor creates one interceptor for each in-memory workflow instance. The same interceptor object handles inbound and outbound calls for that instance and is recreated if the workflow is evicted and rebuilt. Inbound interceptors are called in regsitration order and outbound interceptors are called in reverse order.

Provided Methods

fn initialize_workflow( &self, _ctx: WorkflowContextView, input: InitializeWorkflowInput, next: WorkflowNext<'_, InitializeWorkflowInput, InitializeWorkflowOutput>, ) -> InitializeWorkflowOutput

Called to invoke the workflow’s #[init] method.

It is only called for workflows that define #[init], before the workflow instance exists.

fn execute<'a>( &'a self, _ctx: WorkflowInterceptorContext, input: ExecuteWorkflowInput, next: WorkflowNext<'a, ExecuteWorkflowInput, WorkflowInterceptorFuture<'a, Result<Box<dyn WorkflowOutputValue>, WorkflowTermination>>>, ) -> WorkflowInterceptorFuture<'a, Result<Box<dyn WorkflowOutputValue>, WorkflowTermination>>

Called to invoke the workflow run method.

Inputs consumed by #[init] are instead passed to WorkflowInterceptor::initialize_workflow.

fn handle_signal<'a>( &'a self, _ctx: WorkflowInterceptorContext, input: HandleSignalInput, next: WorkflowNext<'a, HandleSignalInput, WorkflowInterceptorFuture<'a, Result<(), WorkflowError>>>, ) -> WorkflowInterceptorFuture<'a, Result<(), WorkflowError>>

Called to invoke a signal handler.

fn handle_update<'a>( &'a self, _ctx: WorkflowInterceptorContext, input: HandleUpdateInput, next: WorkflowNext<'a, HandleUpdateInput, WorkflowInterceptorFuture<'a, Result<Box<dyn WorkflowOutputValue>, WorkflowError>>>, ) -> WorkflowInterceptorFuture<'a, Result<Box<dyn WorkflowOutputValue>, WorkflowError>>

Called to invoke an update handler.

fn handle_query( &self, _ctx: SyncWorkflowInterceptorContext, input: HandleQueryInput, next: WorkflowNext<'_, HandleQueryInput, Result<Box<dyn WorkflowOutputValue>, WorkflowError>>, ) -> Result<Box<dyn WorkflowOutputValue>, WorkflowError>

Called to invoke a query handler.

fn validate_update( &self, _ctx: SyncWorkflowInterceptorContext, input: ValidateUpdateInput, next: WorkflowNext<'_, ValidateUpdateInput, Result<(), WorkflowError>>, ) -> Result<(), WorkflowError>

Called to validate an update.

fn start_timer( &self, _ctx: WorkflowInterceptorContext, input: StartTimerInput, next: WorkflowNext<'static, StartTimerInput, CancellableWorkflowOutboundFuture<TimerResult>>, ) -> CancellableWorkflowOutboundFuture<TimerResult>

Called when the workflow starts a timer.

fn schedule_activity( &self, _ctx: WorkflowInterceptorContext, input: ScheduleActivityInput, next: WorkflowNext<'static, ScheduleActivityInput, CancellableWorkflowOutboundFuture<Result<Box<dyn WorkflowOutboundValue>, ActivityExecutionError>>>, ) -> CancellableWorkflowOutboundFuture<Result<Box<dyn WorkflowOutboundValue>, ActivityExecutionError>>

Called when the workflow schedules an activity.

fn schedule_local_activity( &self, _ctx: WorkflowInterceptorContext, input: ScheduleLocalActivityInput, next: WorkflowNext<'static, ScheduleLocalActivityInput, CancellableWorkflowOutboundFuture<Result<Box<dyn WorkflowOutboundValue>, ActivityExecutionError>>>, ) -> CancellableWorkflowOutboundFuture<Result<Box<dyn WorkflowOutboundValue>, ActivityExecutionError>>

Called when the workflow schedules a local activity.

fn start_child_workflow( &self, _ctx: WorkflowInterceptorContext, input: StartChildWorkflowInput, next: WorkflowNext<'static, StartChildWorkflowInput, CancellableWorkflowOutboundFuture<Result<StartChildWorkflowOutput, ChildWorkflowStartError>>>, ) -> CancellableWorkflowOutboundFuture<Result<StartChildWorkflowOutput, ChildWorkflowStartError>>

Called when the workflow starts a child workflow.

fn signal_workflow( &self, _ctx: WorkflowInterceptorContext, input: SignalWorkflowInput, next: WorkflowNext<'static, SignalWorkflowInput, CancellableWorkflowOutboundFuture<Result<(), WorkflowSignalError>>>, ) -> CancellableWorkflowOutboundFuture<Result<(), WorkflowSignalError>>

Called when the workflow signals a child or external workflow.

fn cancel_external_workflow( &self, _ctx: WorkflowInterceptorContext, input: CancelExternalWorkflowInput, next: WorkflowNext<'static, CancelExternalWorkflowInput, WorkflowOutboundFuture<Result<CancelExternalOk, Failure>>>, ) -> WorkflowOutboundFuture<Result<CancelExternalOk, Failure>>

Called when the workflow requests cancellation of an external workflow.

fn continue_as_new( &self, _ctx: SyncWorkflowInterceptorContext, input: ContinueAsNewInput, next: WorkflowNext<'static, ContinueAsNewInput, Result<Infallible, WorkflowTermination>>, ) -> Result<Infallible, WorkflowTermination>

Called when the workflow continues as new.

fn start_nexus_operation( &self, _ctx: WorkflowInterceptorContext, input: StartNexusOperationInput, next: WorkflowNext<'static, StartNexusOperationInput, CancellableWorkflowOutboundFuture<Result<StartedNexusOperation, Failure>>>, ) -> CancellableWorkflowOutboundFuture<Result<StartedNexusOperation, Failure>>

Called when the workflow starts a Nexus operation.

Dyn Compatibility

This trait is dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety".

Implementors