File size: 3,364 Bytes
16cdcb7 | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 | package subscription
import (
"context"
"fmt"
"github.com/qmuntal/stateless"
"github.com/openmeterio/openmeter/pkg/models"
)
type SubscriptionStatus string
const (
// Active means the subscription is active and the customer is being billed
SubscriptionStatusActive SubscriptionStatus = "active"
// Canceled means the subscription has already been canceled but is still active
SubscriptionStatusCanceled SubscriptionStatus = "canceled"
// Inactive means the subscription is inactive (might have been previously active) and the customer is not being billed
SubscriptionStatusInactive SubscriptionStatus = "inactive"
// Scheduled means the subscription is scheduled to be active in the future
SubscriptionStatusScheduled SubscriptionStatus = "scheduled"
)
func (s SubscriptionStatus) Values() []SubscriptionStatus {
return []SubscriptionStatus{
SubscriptionStatusActive,
SubscriptionStatusCanceled,
SubscriptionStatusInactive,
SubscriptionStatusScheduled,
}
}
func (s SubscriptionStatus) Validate() error {
switch s {
case SubscriptionStatusActive, SubscriptionStatusCanceled, SubscriptionStatusInactive, SubscriptionStatusScheduled:
return nil
default:
return fmt.Errorf("invalid subscription status: %s", s)
}
}
type SubscriptionAction string
const (
SubscriptionActionCreate SubscriptionAction = "create"
SubscriptionActionUpdate SubscriptionAction = "update"
SubscriptionActionCancel SubscriptionAction = "cancel"
SubscriptionActionContinue SubscriptionAction = "continue"
SubscriptionActionDelete SubscriptionAction = "delete"
SubscriptionActionChangeAddons SubscriptionAction = "change_addons"
)
// SubscriptionStateMachine is a very simple state machine that determines what actions can be taken on a Subscription
type SubscriptionStateMachine struct {
sm *stateless.StateMachine
}
func (sm SubscriptionStateMachine) CanTransitionOrErr(ctx context.Context, action SubscriptionAction) error {
can, err := sm.sm.CanFireCtx(ctx, action)
// If there was an error, let's just log it and return false
if err != nil {
return fmt.Errorf("failed to check if transition is possible: %w", err)
}
state, err := sm.sm.State(ctx)
if err != nil {
return fmt.Errorf("failed to get current state: %w", err)
}
status, ok := state.(SubscriptionStatus)
if !ok {
return fmt.Errorf("failed to cast state to SubscriptionStatus, got %T %v", state, state)
}
if err := status.Validate(); err != nil {
return fmt.Errorf("invalid state: %w", err)
}
if !can {
return models.NewGenericForbiddenError(
fmt.Errorf("transition %s in state %s not allowed", action, state),
)
}
return nil
}
func NewStateMachine(status SubscriptionStatus) SubscriptionStateMachine {
sm := stateless.NewStateMachine(status)
sm.Configure(SubscriptionStatusInactive).
Permit(SubscriptionActionCreate, SubscriptionStatusActive)
sm.Configure(SubscriptionStatusActive).
PermitReentry(SubscriptionActionUpdate).
PermitReentry(SubscriptionActionChangeAddons).
Permit(SubscriptionActionCancel, SubscriptionStatusCanceled)
sm.Configure(SubscriptionStatusCanceled).
Permit(SubscriptionActionContinue, SubscriptionStatusActive)
sm.Configure(SubscriptionStatusScheduled).
Permit(SubscriptionActionDelete, nil) // Delete deletes the state too
return SubscriptionStateMachine{
sm: sm,
}
}
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