upgradedatabase

type Clock interface {
	// Now returns the current clock time.
	Now() time.Time

	// After waits for the duration to elapse and then sends the
	// current time on the returned channel.
	After(time.Duration) <-chan time.Time
}

type Config struct {
	// UpgradeComplete is a lock used to synchronise workers that must start
	// after database upgrades are verified as completed.
	UpgradeComplete gate.Lock

	// Tag is the current machine tag.
	Tag names.Tag

	// agent is the running machine agent.
	Agent agent.Agent

	// Logger is the logger for this worker.
	Logger Logger

	// Open state is a function pointer for returning a state pool indirection.
	OpenState func() (Pool, error)

	// PerformUpgrade is a function pointer for executing the DB upgrade steps.
	// Context retrieval is lazy because because it requires a real
	// state.StatePool that we cast our Pool indirection back to.
	// We need the concrete type, because we are unable to indirect all the
	// state methods that upgrade steps might require.
	// This is OK for in-theatre operation, but is not suitable for testing.
	PerformUpgrade func(version.Number, []upgrades.Target, func() upgrades.Context) error

	// RetryStrategy is the strategy to use for re-attempting failed upgrades.
	RetryStrategy retry.CallArgs

	// Clock is used to enforce time-out logic for controllers waiting for the
	// master MongoDB upgrades to execute.
	Clock Clock
}

type Logger interface {
	Debugf(message string, args ...interface{})
	Infof(message string, args ...interface{})
	Errorf(message string, args ...interface{})
}

type ManifoldConfig struct {
	AgentName         string
	UpgradeDBGateName string
	Logger            Logger
	OpenState         func() (*state.StatePool, error)
	Clock             Clock
}

type Pool interface {
	// IsPrimary returns true if the Mongo primary is
	// running on the machine with the input ID.
	IsPrimary(string) (bool, error)

	// SetStatus updates the status of the machine with the input ID.
	SetStatus(string, status.Status, string) error

	// EnsureUpgradeInfo ensures that a document exists in the "upgradeInfo"
	// collection for coordinating the current upgrade.
	EnsureUpgradeInfo(string, version.Number, version.Number) (UpgradeInfo, error)

	// Close closes the state pool.
	Close() error
}

type UpgradeInfo interface {
	// Status returns the current status of the upgrade.
	Status() state.UpgradeStatus

	// SetStatus sets the current status of the upgrade.
	SetStatus(status state.UpgradeStatus) error

	// Watch returns a watcher that notifies of changes to the UpgradeInfo.
	Watch() state.NotifyWatcher

	// Refresh refreshes the UpgradeInfo from state.
	Refresh() error
}