tasks/chasm/component.go

//go:generate mockgen -package $GOPACKAGE -source $GOFILE -destination component_mock.go

package chasm

import (
	"context"
	"reflect"
	"strconv"

	commonpb "go.temporal.io/api/common/v1"
)

type Component interface {
	LifecycleState(Context) LifecycleState

	Terminate(MutableContext, TerminateComponentRequest) (TerminateComponentResponse, error)

	// we may not need this in the beginning
	mustEmbedUnimplementedComponent()
}

type TerminateComponentRequest struct {
	Identity string
	Reason   string
	Details  *commonpb.Payloads
}

type TerminateComponentResponse struct{}

// Embed UnimplementedComponent to get forward compatibility
type UnimplementedComponent struct{}

func (UnimplementedComponent) LifecycleState(Context) LifecycleState {
	return LifecycleStateUnspecified
}

func (UnimplementedComponent) Terminate(MutableContext, TerminateComponentRequest) (TerminateComponentResponse, error) {
	return TerminateComponentResponse{}, nil
}

func (UnimplementedComponent) mustEmbedUnimplementedComponent() {}

var UnimplementedComponentT = reflect.TypeFor[UnimplementedComponent]()

// Shall it be named ComponentLifecycleState?
type LifecycleState int

const (
	// Lifecycle states that are considered OPEN
	//
	// LifecycleStateCreated LifecycleState = 1 << iota
	LifecycleStateRunning LifecycleState = 2 << iota
	// LifecycleStatePaused

	// Lifecycle states that are considered CLOSED
	//
	LifecycleStateCompleted
	LifecycleStateFailed
	// LifecycleStateTerminated
	// LifecycleStateTimedout
	// LifecycleStateReset

	LifecycleStateUnspecified = LifecycleState(0)
)

func (s LifecycleState) IsClosed() bool {
	return s == LifecycleStateCompleted || s == LifecycleStateFailed
}

func (s LifecycleState) String() string {
	switch s {
	case LifecycleStateUnspecified:
		return "Unspecified"
	case LifecycleStateRunning:
		return "Running"
	case LifecycleStateCompleted:
		return "Completed"
	case LifecycleStateFailed:
		return "Failed"
	default:
		return strconv.Itoa(int(s))
	}
}

type OperationIntent int

const (
	OperationIntentProgress OperationIntent = 1 << iota
	OperationIntentObserve

	OperationIntentUnspecified = OperationIntent(0)
)

// The operation intent must come from the context
// as the handler may not pass the endpoint request as Input to,
// say, the chasm.UpdateComponent method.
// So similar to the chasm engine, handler needs to add the intent
// to the context.
type operationIntentCtxKeyType string

const operationIntentCtxKey engineCtxKeyType = "chasmOperationIntent"

func newContextWithOperationIntent(
	ctx context.Context,
	intent OperationIntent,
) context.Context {
	return context.WithValue(ctx, operationIntentCtxKey, intent)
}

func operationIntentFromContext(
	ctx context.Context,
) OperationIntent {
	intent, ok := ctx.Value(engineCtxKey).(OperationIntent)
	if !ok {
		return OperationIntentUnspecified
	}
	return intent
}