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Continue-As-New - Go SDK

Continue-As-New enables a Workflow Execution to close successfully and create a new Workflow Execution in a single atomic operation if the number of Events in the Event History is becoming too large. The Workflow Execution spawned from the use of Continue-As-New has the same Workflow Id, a new Run Id, and a fresh Event History and is passed all the appropriate parameters.

To cause a Workflow Execution to Continue-As-New, the Workflow API should return the result of the NewContinueAsNewError() function available from the go.temporal.io/sdk/workflow package.

func SimpleWorkflow(ctx workflow.Context, value string) error {
    ...
    return workflow.NewContinueAsNewError(ctx, SimpleWorkflow, value)
}

To check whether a Workflow Execution was spawned as a result of Continue-As-New, you can check if workflow.GetInfo(ctx).ContinuedExecutionRunID is not empty (i.e. "").

Notes

  • To prevent Signal loss, be sure to perform an asynchronous drain on the Signal channel. Failure to do so can result in buffered Signals being ignored and lost.
  • Make sure that the previous Workflow and the Continue-As-New Workflow are referenced by the same alias. Failure to do so can cause the Workflow to Continue-As-New on an entirely different Workflow.
Using Continue-as-New and Updates
  • Temporal does not support Continue-as-New functionality within Update handlers.
  • Complete all handlers before using Continue-as-New.
  • Use Continue-as-New from your main Workflow Definition method, just as you would complete or fail a Workflow Execution.