refactor: drop application from the lease manager getter

Application is the implementation detail of the model lease manager
getter. We could have another implementation that is for singular
controllers. The interface shouldn't care. It's just offering out
a given type.

core/lease/lease.go

@@ -12,16 +12,17 @@ type LeaseCheckerWaiter interface {
 	Checker
 }
 
-// ApplicationLeaseManagerGetter is an interface that provides a method to get a
-// lease manager for a given application using its UUID.
-type ApplicationLeaseManagerGetter interface {
+// LeaseManagerGetter is an interface that provides a method to get a lease
+// manager for a given lease using its UUID. The lease namespace could be a
+// model or an application.
+type LeaseManagerGetter interface {
 	// GetLeaseManager returns a lease manager for the given model UUID.
 	GetLeaseManager(model.UUID) (LeaseCheckerWaiter, error)
 }
 
-// ModelApplicationLeaseManagerGetter is an interface that provides a method to
+// ModelLeaseManagerGetter is an interface that provides a method to
 // get a lease manager in the scope of a model.
-type ModelApplicationLeaseManagerGetter interface {
+type ModelLeaseManagerGetter interface {
 	// GetLeaseManager returns a lease manager for the given model UUID.
 	GetLeaseManager() (LeaseCheckerWaiter, error)
 }

domain/leaseservice.go

@@ -12,11 +12,11 @@ import (
 
 // LeaseService creates a base service that offers lease capabilities.
 type LeaseService struct {
-	leaseChecker lease.ModelApplicationLeaseManagerGetter
+	leaseChecker lease.ModelLeaseManagerGetter
 }
 
 // NewLeaseService creates a new LeaseService.
-func NewLeaseService(leaseChecker lease.ModelApplicationLeaseManagerGetter) *LeaseService {
+func NewLeaseService(leaseChecker lease.ModelLeaseManagerGetter) *LeaseService {
 	return &LeaseService{
 		leaseChecker: leaseChecker,
 	}
@@ -31,7 +31,7 @@ func (s *LeaseService) WithLease(ctx context.Context, leaseName, holderName stri
 	// Holding the lease is quite a complex operation, so we need to ensure that
 	// the context is not cancelled before we start the operation.
 	if err := ctx.Err(); err != nil {
-		return internalerrors.Errorf("lease prechecking").Add(ctx.Err())
+		return internalerrors.Errorf("lease pre-checking").Add(ctx.Err())
 	}
 
 	leaseChecker, err := s.leaseChecker.GetLeaseManager()

domain/leaseservice_test.go

@@ -19,7 +19,7 @@ import (
 type leaseServiceSuite struct {
 	testing.IsolationSuite
 
-	modelLeaseManager  *MockModelApplicationLeaseManagerGetter
+	modelLeaseManager  *MockModelLeaseManagerGetter
 	leaseCheckerWaiter *MockLeaseCheckerWaiter
 	token              *MockToken
 }
@@ -176,7 +176,7 @@ func (s *leaseServiceSuite) TestWithLeaseFailsOnWaitCheck(c *gc.C) {
 func (s *leaseServiceSuite) setupMocks(c *gc.C) *gomock.Controller {
 	ctrl := gomock.NewController(c)
 
-	s.modelLeaseManager = NewMockModelApplicationLeaseManagerGetter(ctrl)
+	s.modelLeaseManager = NewMockModelLeaseManagerGetter(ctrl)
 	s.leaseCheckerWaiter = NewMockLeaseCheckerWaiter(ctrl)
 	s.token = NewMockToken(ctrl)
 

domain/package_test.go

@@ -11,7 +11,7 @@ import (
 )
 
 //go:generate go run go.uber.org/mock/mockgen -typed -package domain -destination changestream_mock_test.go github.com/juju/juju/core/changestream Subscription,EventSource
-//go:generate go run go.uber.org/mock/mockgen -typed -package domain -destination lease_mock_test.go github.com/juju/juju/core/lease Token,LeaseCheckerWaiter,ModelApplicationLeaseManagerGetter
+//go:generate go run go.uber.org/mock/mockgen -typed -package domain -destination lease_mock_test.go github.com/juju/juju/core/lease Token,LeaseCheckerWaiter,ModelLeaseManagerGetter
 
 func TestPackage(t *testing.T) {
 	defer goleak.VerifyNone(t)

domain/services/model.go

@@ -87,7 +87,7 @@ type ModelFactory struct {
 	objectstore       objectstore.ModelObjectStoreGetter
 	storageRegistry   corestorage.ModelStorageRegistryGetter
 	publicKeyImporter PublicKeyImporter
-	leaseManager      lease.ModelApplicationLeaseManagerGetter
+	leaseManager      lease.ModelLeaseManagerGetter
 }
 
 // NewModelFactory returns a new registry which uses the provided modelDB
@@ -100,7 +100,7 @@ func NewModelFactory(
 	objectStore objectstore.ModelObjectStoreGetter,
 	storageRegistry corestorage.ModelStorageRegistryGetter,
 	publicKeyImporter PublicKeyImporter,
-	leaseManager lease.ModelApplicationLeaseManagerGetter,
+	leaseManager lease.ModelLeaseManagerGetter,
 	clock clock.Clock,
 	logger logger.Logger,
 ) *ModelFactory {

domain/services/service.go

@@ -33,7 +33,7 @@ func NewDomainServices(
 	objectStore objectstore.ModelObjectStoreGetter,
 	storageRegistry storage.ModelStorageRegistryGetter,
 	publicKeyImporter PublicKeyImporter,
-	leaseManager lease.ModelApplicationLeaseManagerGetter,
+	leaseManager lease.ModelLeaseManagerGetter,
 	clock clock.Clock,
 	logger logger.Logger,
 ) *DomainServices {