Add Managed Failover (cadence-workflow#3558)

common/domain/handler.go

@@ -426,7 +426,7 @@ func (d *HandlerImpl) UpdateDomain(
 		return nil, err
 	}
 
-	//Update replication config
+	// Update replication config
 	replicationConfig, replicationConfigChanged, activeClusterChanged, err := d.updateReplicationConfig(
 		replicationConfig,
 		updateRequest.ReplicationConfiguration,

common/service/dynamicconfig/constants.go

@@ -69,6 +69,7 @@ var keys = map[Key]string{
 	DisallowQuery:                       "system.disallowQuery",
 	EnableBatcher:                       "worker.enableBatcher",
 	EnableParentClosePolicyWorker:       "system.enableParentClosePolicyWorker",
+	EnableFailoverManager:               "system.enableFailoverManager",
 	EnableStickyQuery:                   "system.enableStickyQuery",
 	EnablePriorityTaskProcessor:         "system.enablePriorityTaskProcessor",
 	EnableAuthorization:                 "system.enableAuthorization",
@@ -845,6 +846,8 @@ const (
 	EnableParentClosePolicyWorker
 	// EnableStickyQuery indicates if sticky query should be enabled per domain
 	EnableStickyQuery
+	// EnableFailoverManager indicates if failover manager is enabled
+	EnableFailoverManager
 
 	//ReplicationTaskFetcherParallelism determines how many go routines we spin up for fetching tasks
 	ReplicationTaskFetcherParallelism

service/worker/failovermanager/starter.go

@@ -0,0 +1,105 @@
+// Copyright (c) 2017-2020 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 failovermanager
+
+import (
+	"context"
+
+	"github.com/opentracing/opentracing-go"
+	"github.com/uber-go/tally"
+	"go.uber.org/cadence/.gen/go/cadence/workflowserviceclient"
+	"go.uber.org/cadence/worker"
+
+	"github.com/uber/cadence/client"
+	"github.com/uber/cadence/common"
+	"github.com/uber/cadence/common/cluster"
+	"github.com/uber/cadence/common/log"
+	"github.com/uber/cadence/common/log/tag"
+	"github.com/uber/cadence/common/metrics"
+	"github.com/uber/cadence/common/service/dynamicconfig"
+)
+
+type (
+
+	// Config defines the configuration for failover
+	Config struct {
+		AdminOperationToken dynamicconfig.StringPropertyFn
+		// ClusterMetadata contains the metadata for this cluster
+		ClusterMetadata cluster.Metadata
+	}
+
+	// BootstrapParams contains the set of params needed to bootstrap
+	// failover manager
+	BootstrapParams struct {
+		// Config contains the configuration for scanner
+		Config Config
+		// ServiceClient is an instance of cadence service client
+		ServiceClient workflowserviceclient.Interface
+		// MetricsClient is an instance of metrics object for emitting stats
+		MetricsClient metrics.Client
+		Logger        log.Logger
+		// TallyScope is an instance of tally metrics scope
+		TallyScope tally.Scope
+		// ClientBean is an instance of client.Bean for a collection of clients
+		ClientBean client.Bean
+	}
+
+	// FailoverManager of cadence worker service
+	FailoverManager struct {
+		cfg           Config
+		svcClient     workflowserviceclient.Interface
+		clientBean    client.Bean
+		metricsClient metrics.Client
+		tallyScope    tally.Scope
+		logger        log.Logger
+		worker        worker.Worker
+	}
+)
+
+// New returns a new instance of FailoverManager
+func New(params *BootstrapParams) *FailoverManager {
+	return &FailoverManager{
+		cfg:           params.Config,
+		svcClient:     params.ServiceClient,
+		metricsClient: params.MetricsClient,
+		tallyScope:    params.TallyScope,
+		logger:        params.Logger.WithTags(tag.ComponentBatcher),
+		clientBean:    params.ClientBean,
+	}
+}
+
+// Start starts the worker
+func (s *FailoverManager) Start() error {
+	ctx := context.WithValue(context.Background(), failoverManagerContextKey, s)
+	workerOpts := worker.Options{
+		MetricsScope:              s.tallyScope,
+		BackgroundActivityContext: ctx,
+		Tracer:                    opentracing.GlobalTracer(),
+	}
+	failoverWorker := worker.New(s.svcClient, common.SystemLocalDomainName, TaskListName, workerOpts)
+	s.worker = failoverWorker
+	return failoverWorker.Start()
+}
+
+// Stop stops the worker
+func (s *FailoverManager) Stop() {
+	s.worker.Stop()
+}