tasks/service/history/workflow/relocatable_attributes_fetcher.go

// The MIT License
//
// Copyright (c) 2020 Temporal Technologies Inc.  All rights reserved.
//
// Copyright (c) 2020 Uber Technologies, Inc.
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.

package workflow

import (
	"context"

	commonpb "go.temporal.io/api/common/v1"

	"go.temporal.io/server/common/persistence/visibility/manager"
)

// RelocatableAttributesFetcher is used to fetch the relocatable attributes from the mutable state.
// Relocatable attributes are attributes that can be moved from the mutable state to the persistence backend.
type RelocatableAttributesFetcher interface {
	Fetch(
		ctx context.Context,
		mutableState MutableState,
	) (*RelocatableAttributes, error)
}

// RelocatableAttributesFetcherProvider provides a new instance of a RelocatableAttributesFetcher.
// The manager.VisibilityManager parameter is used to fetch the relocatable attributes from the persistence backend iff
// we already moved them there out from the mutable state.
// The visibility manager is not used if the relocatable attributes are still in the mutable state.
// We detect that the fields have moved by checking if the CloseExecutionVisibilityTask for this workflow execution is
// marked as complete in the mutable state.
// Because the relocatable fields that we push to persistence are never updated thereafter,
// we may cache them on a per-workflow execution basis.
// Currently, there is no cache, but you may provide a manager.VisibilityManager that supports caching to this function
// safely.
// TODO: Add a cache around the visibility manager for the relocatable attributes.
func RelocatableAttributesFetcherProvider(
	visibilityManager manager.VisibilityManager,
) RelocatableAttributesFetcher {
	return &relocatableAttributesFetcher{
		visibilityManager: visibilityManager,
	}
}

// RelocatableAttributes contains workflow attributes that can be moved from the mutable state to the persistence
// backend.
type RelocatableAttributes struct {
	Memo             *commonpb.Memo
	SearchAttributes *commonpb.SearchAttributes
}

// relocatableAttributesFetcher is the default implementation of RelocatableAttributesFetcher.
type relocatableAttributesFetcher struct {
	visibilityManager manager.VisibilityManager
}

// Fetch fetches the relocatable attributes from the mutable state or the persistence backend.
// First, it checks if the close visibility task is completed. If it is completed, then the relocatable attributes
// are fetched from the persistence backend. Otherwise, the relocatable attributes are fetched from the mutable state.
func (f *relocatableAttributesFetcher) Fetch(
	ctx context.Context,
	mutableState MutableState,
) (*RelocatableAttributes, error) {
	executionInfo := mutableState.GetExecutionInfo()
	// If we haven't processed close visibility task yet, then we can fetch the search attributes and memo from the
	// mutable state.
	if !executionInfo.GetCloseVisibilityTaskCompleted() {
		return &RelocatableAttributes{
			Memo:             &commonpb.Memo{Fields: executionInfo.Memo},
			SearchAttributes: &commonpb.SearchAttributes{IndexedFields: executionInfo.SearchAttributes},
		}, nil
	}

	// If we have processed close visibility task, then we need to fetch the search attributes and memo from the
	// persistence backend because we have already deleted them from the mutable state.
	executionState := mutableState.GetExecutionState()
	visResponse, err := f.visibilityManager.GetWorkflowExecution(
		ctx,
		&manager.GetWorkflowExecutionRequest{
			NamespaceID: mutableState.GetNamespaceEntry().ID(),
			Namespace:   mutableState.GetNamespaceEntry().Name(),
			RunID:       executionState.GetRunId(),
			WorkflowID:  executionInfo.GetWorkflowId(),
		},
	)
	if err != nil {
		return nil, err
	}
	return &RelocatableAttributes{
		Memo:             visResponse.Execution.Memo,
		SearchAttributes: visResponse.Execution.SearchAttributes,
	}, nil
}