policycontroller

type Actuator ¶

type Actuator[P any] interface {
	Act(ctx context.Context, plan P) error
}

Actuator applies a plan produced by an Evaluator.

type ActuatorFunc ¶

type ActuatorFunc[P any] func(ctx context.Context, plan P) error

ActuatorFunc adapts a function into an Actuator.

func (f ActuatorFunc[P]) Act(ctx context.Context, plan P) error

type Controller ¶

type Controller[T any, P any] struct {
	Observer  Observer[T]
	Evaluator Evaluator[T, P]
	Actuator  Actuator[P]

	Logger *slog.Logger
}

Controller runs a single-pass (Reconcile) or looped (Run) policy controller.

func (c *Controller[T, P]) Reconcile(ctx context.Context) (Result[T, P], error)

func (c *Controller[T, P]) Run(ctx context.Context, interval time.Duration) error

type Decision ¶

type Decision[P any] struct {
	ShouldAct bool
	Plan      P
	Reason    string
}

Decision is the output of an evaluation pass.

If ShouldAct is false, the Controller will not call the Actuator.

type Evaluator ¶

type Evaluator[T any, P any] interface {
	Evaluate(ctx context.Context, observed T) (Decision[P], error)
}

Evaluator compares observed state to its policy and returns a decision.

Policy is intentionally not modeled as a separate input: callers can embed policy in T, close over policy in the implementation, or compose it however they like.

type EvaluatorFunc ¶

type EvaluatorFunc[T any, P any] func(ctx context.Context, observed T) (Decision[P], error)

EvaluatorFunc adapts a function into an Evaluator.

func (f EvaluatorFunc[T, P]) Evaluate(ctx context.Context, observed T) (Decision[P], error)

type Observer ¶

type Observer[T any] interface {
	Observe(ctx context.Context) (T, error)
}

Observer returns the current state of some managed collection/system.

type ObserverFunc ¶

type ObserverFunc[T any] func(ctx context.Context) (T, error)

ObserverFunc adapts a function into an Observer.

func (f ObserverFunc[T]) Observe(ctx context.Context) (T, error)

type Result ¶

type Result[T any, P any] struct {
	Observed T
	Decision Decision[P]

	StartedAt  time.Time
	FinishedAt time.Time
	Acted      bool
}