scheduler

type ScheduleResult struct {
	Procedure procedure.Procedure
	// The reason that the procedure is generated for.
	Reason string
}

type Scheduler interface {
	Name() string
	// Schedule will generate procedure based on current cluster snapshot, which will be submitted to ProcedureManager, and whether it is actually executed depends on the current state of ProcedureManager.
	Schedule(ctx context.Context, clusterSnapshot metadata.Snapshot) (ScheduleResult, error)
	// UpdateDeployMode is used to update deployMode for scheduler,
	// DeployMode means that the cluster topology is locked and the mapping between shards and nodes cannot be changed.
	UpdateDeployMode(ctx context.Context, enable bool)
	AddShardAffinityRule(ctx context.Context, rule ShardAffinityRule) error
	RemoveShardAffinityRule(ctx context.Context, shardID storage.ShardID) error
	ListShardAffinityRule(ctx context.Context) (ShardAffinityRule, error)
}

type ShardAffinity struct {
	ShardID               storage.ShardID `json:"shardID"`
	NumAllowedOtherShards uint            `json:"numAllowedOtherShards"`
}

type ShardAffinityRule struct {
	Affinities []ShardAffinity
}