exec

type Action interface {
	// CanRun returns true if all of the Events this Action is waiting for have
	// been signaled.
	CanRun() bool
	// Signal this Action with the Event that has occurred. Returns true if the
	// Action was waiting on the Event being Signaled.
	Signal(Event) bool
	// Run the Action, performing the operations. Returns a list of Events to
	// signal and/or any errors that have occurred.
	Run(context.Context, cloud.Cloud) (EventList, error)
	// DryRun simulates running the Action. Returns a list of Events to signal.
	DryRun() EventList
	// String returns a human-readable representation of the Action for logging.
	String() string

	// PendingEvents is the list of events that this Action is still waiting on.
	PendingEvents() EventList

	// Metadata returns metadata used for visualizations.
	Metadata() *ActionMetadata
}

type ActionBase struct {
	// Want are the events this action is still waiting for.
	Want EventList
	// Done tracks the events that have happened. This is for debugging.
	Done EventList
}

type ActionMetadata struct {
	// Name of this action. This must be unique to the execution graph.
	Name string
	// Type of this action.
	Type ActionType
	// Summary is a human readable description of this action.
	Summary string
}

type ActionType string

type ActionWithErr struct {
	Action Action
	Err    error
}

type ErrorStrategy string

type Event interface {
	// Equal returns true if this event is == to other.
	Equal(other Event) bool
	// String implements Stringer. The values returned by String() must satisfy
	// the same behavior as Equal(), i.e. a.String() == b.String() if and only
	// if a.Equal(b).
	String() string
}

type EventList []Event

type Executor interface {
	// Run the actions. Returns non-nil if there was an error in execution of
	// one or more Actions.
	Run(context.Context) (*Result, error)
}

type ExecutorConfig struct {
	Tracer                Tracer
	DryRun                bool
	ErrorStrategy         ErrorStrategy
	Timeout               time.Duration
	WaitForOrphansTimeout time.Duration
}

type GraphvizTracer struct {
	// contains filtered or unexported fields
}

type Option func(*ExecutorConfig)

type Result struct {
	// Completed Actions with no errors.
	Completed []Action
	// Errors are Actions that failed with an error.
	Errors []ActionWithErr
	// Pending are Actions that could not be executed due to missing
	// preconditions.
	Pending []Action
}

type StringEvent string

type TraceEntry struct {
	Action   Action
	Err      error
	Signaled []TraceSignal

	Start time.Time
	End   time.Time
}

type TraceSignal struct {
	Event          Event
	SignaledAction Action
}

type Tracer interface {
	Record(entry *TraceEntry, err error)
	Finish(pending []Action)
}