continue-as-new-suggested reason and signal

Author: carlydf

go.mod

@@ -14,7 +14,7 @@ require (
 	github.com/nexus-rpc/sdk-go v0.3.0
 	github.com/robfig/cron v1.2.0
 	github.com/stretchr/testify v1.10.0
-	go.temporal.io/api v1.53.0
+	go.temporal.io/api v1.55.1-0.20251017163919-d527807d0d4e
 	golang.org/x/sync v0.13.0
 	golang.org/x/sys v0.32.0
 	golang.org/x/time v0.3.0

go.sum

@@ -35,8 +35,8 @@ github.com/stretchr/testify v1.10.0/go.mod h1:r2ic/lqez/lEtzL7wO/rwa5dbSLXVDPFyf
 github.com/yuin/goldmark v1.1.27/go.mod h1:3hX8gzYuyVAZsxl0MRgGTJEmQBFcNTphYh9decYSb74=
 github.com/yuin/goldmark v1.2.1/go.mod h1:3hX8gzYuyVAZsxl0MRgGTJEmQBFcNTphYh9decYSb74=
 github.com/yuin/goldmark v1.3.5/go.mod h1:mwnBkeHKe2W/ZEtQ+71ViKU8L12m81fl3OWwC1Zlc8k=
-go.temporal.io/api v1.53.0 h1:6vAFpXaC584AIELa6pONV56MTpkm4Ha7gPWL2acNAjo=
-go.temporal.io/api v1.53.0/go.mod h1:iaxoP/9OXMJcQkETTECfwYq4cw/bj4nwov8b3ZLVnXM=
+go.temporal.io/api v1.55.1-0.20251017163919-d527807d0d4e h1:8Y8p3tBzobAYO3KjuoiGXjDxeKlPsrEjjDRfLlB7O7c=
+go.temporal.io/api v1.55.1-0.20251017163919-d527807d0d4e/go.mod h1:iaxoP/9OXMJcQkETTECfwYq4cw/bj4nwov8b3ZLVnXM=
 golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
 golang.org/x/crypto v0.0.0-20191011191535-87dc89f01550/go.mod h1:yigFU9vqHzYiE8UmvKecakEJjdnWj3jj499lnFckfCI=
 golang.org/x/crypto v0.0.0-20200622213623-75b288015ac9/go.mod h1:LzIPMQfyMNhhGPhUkYOs5KpL4U8rLKemX1yGLhDgUto=

internal/client.go

@@ -40,6 +40,9 @@ const (
 
 	// QueryTypeWorkflowMetadata is the query name for the workflow metadata.
 	QueryTypeWorkflowMetadata string = "__temporal_workflow_metadata"
+
+	// SignalTypeSuggestContinueAsNew is the signal name to set ContinueAsNewSuggested=true in the workflow env.
+	SignalTypeSuggestContinueAsNew = "__suggest_continue_as_new"
 )
 
 type (

internal/internal_event_handlers.go

@@ -1199,6 +1199,9 @@ func (weh *workflowExecutionEventHandlerImpl) ProcessEvent(
 		// Update workflow info fields
 		weh.workflowInfo.currentHistoryLength = int(event.EventId)
 		weh.workflowInfo.continueAsNewSuggested = event.GetWorkflowTaskStartedEventAttributes().GetSuggestContinueAsNew()
+		weh.workflowInfo.continueAsNewSuggestedReason = convertContinueAsNewSuggestedReason(
+			event.GetWorkflowTaskStartedEventAttributes().GetContinueAsNewSuggestedReason(),
+		)
 		weh.workflowInfo.currentHistorySize = int(event.GetWorkflowTaskStartedEventAttributes().GetHistorySizeBytes())
 		// Reset the counter on command helper used for generating ID for commands
 		weh.commandsHelper.setCurrentWorkflowTaskStartedEventID(event.GetEventId())
@@ -1751,9 +1754,35 @@ func (weh *workflowExecutionEventHandlerImpl) ProcessLocalActivityResult(lar *lo
 func (weh *workflowExecutionEventHandlerImpl) handleWorkflowExecutionSignaled(
 	attributes *historypb.WorkflowExecutionSignaledEventAttributes,
 ) error {
+	switch attributes.GetSignalName() {
+	case SignalTypeSuggestContinueAsNew:
+		weh.workflowInfo.continueAsNewSuggested = true
+		var reason enumspb.ContinueAsNewSuggestedReason
+		err := weh.dataConverter.FromPayload(attributes.GetInput().GetPayloads()[0], &reason)
+		if err != nil {
+			return fmt.Errorf("unable to convert continue-as-new suggested reason: %w", err)
+		}
+		weh.workflowInfo.continueAsNewSuggestedReason = convertContinueAsNewSuggestedReason(reason)
+	}
 	return weh.signalHandler(attributes.GetSignalName(), attributes.Input, attributes.Header)
 }
 
+// TODO(carlydf): move this helper somewhere appropriate
+func convertContinueAsNewSuggestedReason(reason enumspb.ContinueAsNewSuggestedReason) ContinueAsNewSuggestedReason {
+	switch reason {
+	case enumspb.CONTINUE_AS_NEW_SUGGESTED_REASON_UNSPECIFIED:
+		return ContinueAsNewSuggestedReasonUnspecified
+	case enumspb.CONTINUE_AS_NEW_SUGGESTED_REASON_UPDATE_REGISTRY_TOO_LARGE:
+		return ContinueAsNewSuggestedReasonUpdateRegistryTooLarge
+	case enumspb.CONTINUE_AS_NEW_SUGGESTED_REASON_HISTORY_SIZE_TOO_LARGE:
+		return ContinueAsNewSuggestedReasonHistorySizeTooLarge
+	case enumspb.CONTINUE_AS_NEW_SUGGESTED_REASON_WORKER_DEPLOYMENT_VERSION_CHANGED:
+		return ContinueAsNewSuggestedReasonWorkerDeploymentVersionChanged
+	default:
+		return ContinueAsNewSuggestedReasonUnspecified
+	}
+}
+
 func (weh *workflowExecutionEventHandlerImpl) handleStartChildWorkflowExecutionFailed(event *historypb.HistoryEvent) error {
 	attributes := event.GetStartChildWorkflowExecutionFailedEventAttributes()
 	childWorkflowID := attributes.GetWorkflowId()

internal/workflow.go

@@ -69,6 +69,39 @@ const (
 	VersioningBehaviorAutoUpgrade
 )
 
+// ContinueAsNewSuggestedReason specifies why ContinueAsNewSuggested is true.
+//
+// NOTE: Experimental
+//
+// Exposed as: [go.temporal.io/sdk/workflow.ContinueAsNewSuggestedReason]
+type ContinueAsNewSuggestedReason int
+
+const (
+	// ContinueAsNewSuggestedReasonUnspecified - ContinueAsNewSuggestedReason unknown.
+	// Reason will be Unspecified if the server is not configured to suggest continue as new,
+	// if the server is not configured to provide a reason for continue as new suggested, or
+	// if continue as new is not suggested.
+	//
+	// Exposed as: [go.temporal.io/sdk/workflow.ContinueAsNewSuggestedReasonUnspecified]
+	ContinueAsNewSuggestedReasonUnspecified ContinueAsNewSuggestedReason = iota
+
+	// ContinueAsNewSuggestedReasonHistorySizeTooLarge - Workflow History size is getting too large.
+	//
+	// Exposed as: [go.temporal.io/sdk/workflow.ContinueAsNewSuggestedReasonHistorySizeTooLarge]
+	ContinueAsNewSuggestedReasonHistorySizeTooLarge
+
+	// ContinueAsNewSuggestedReasonUpdateRegistryTooLarge - Workflow Update registry is getting too large.
+	//
+	// Exposed as: [go.temporal.io/sdk/workflow.ContinueAsNewSuggestedReasonUpdateRegistryTooLarge]
+	ContinueAsNewSuggestedReasonUpdateRegistryTooLarge
+
+	// ContinueAsNewSuggestedReasonWorkerDeploymentVersionChanged - Workflow's Worker Deployment has a new Ramping
+	// Version or Current Version, and the workflow's Versioning Behavior is PinnedUntilContinueAsNew.
+	//
+	// Exposed as: [go.temporal.io/sdk/workflow.ContinueAsNewSuggestedReasonWorkerDeploymentVersionChanged]
+	ContinueAsNewSuggestedReasonWorkerDeploymentVersionChanged
+)
+
 // NexusOperationCancellationType specifies what action should be taken for a Nexus operation when the
 // caller is cancelled.
 //
@@ -1350,9 +1383,10 @@ type WorkflowInfo struct {
 	// this worker
 	currentTaskBuildID string
 
-	continueAsNewSuggested bool
-	currentHistorySize     int
-	currentHistoryLength   int
+	continueAsNewSuggested       bool
+	continueAsNewSuggestedReason ContinueAsNewSuggestedReason
+	currentHistorySize           int
+	currentHistoryLength         int
 	// currentRunID is the current run ID of the workflow task, deterministic over reset
 	currentRunID string
 }
@@ -1404,6 +1438,12 @@ func (wInfo *WorkflowInfo) GetContinueAsNewSuggested() bool {
 	return wInfo.continueAsNewSuggested
 }
 
+// GetContinueAsNewSuggestedReason returns the reason for ContinueAsNewSuggested if one exists.
+// This value may change throughout the life of the workflow.
+func (wInfo *WorkflowInfo) GetContinueAsNewSuggestedReason() ContinueAsNewSuggestedReason {
+	return wInfo.continueAsNewSuggestedReason
+}
+
 // GetWorkflowInfo extracts info of a current workflow from a context.
 //
 // Exposed as: [go.temporal.io/sdk/workflow.GetInfo]

workflow/deterministic_wrappers.go

@@ -53,6 +53,11 @@ type (
 	//
 	// NOTE: Experimental
 	AwaitOptions = internal.AwaitOptions
+
+	// ContinueAsNewSuggestedReason is the reason for ContinueAsNewSuggested
+	//
+	// NOTE: Experimental
+	ContinueAsNewSuggestedReason = internal.ContinueAsNewSuggestedReason
 )
 
 // Await blocks the calling thread until condition() returns true.