refactor: simplify model lease manager

Instead of getting the lease manager twice, just include Waiter in the
interface for checker and get the lease secretary once.

This is a reasonable capability includion into the checker interface and
saves us an unecessasry creation of a second secretary.

core/lease/interface.go

@@ -71,8 +71,9 @@ type Pinner interface {
 	Pinned() (map[string][]string, error)
 }
 
-// Checker exposes facts about lease ownership.
+// Checker exposes facts about lease ownership and expiry.
 type Checker interface {
+	Waiter
 
 	// Token returns a Token that can be interrogated at any time to discover
 	// whether the supplied lease is currently held by the supplied holder.

core/lease/lease.go

@@ -5,24 +5,17 @@ package lease
 
 import "github.com/juju/juju/core/model"
 
-// LeaseCheckerWaiter is an interface that checks and waits if a lease is held
-// by a holder.
-type LeaseCheckerWaiter interface {
-	Waiter
-	Checker
-}
-
 // 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)
+	GetLeaseManager(model.UUID) (Checker, error)
 }
 
 // ModelLeaseManagerGetter is an interface that provides a method to
 // get a lease manager in the scope of a model.
 type ModelLeaseManagerGetter interface {
 	// GetLeaseManager returns a lease manager for the given model UUID.
-	GetLeaseManager() (LeaseCheckerWaiter, error)
+	GetLeaseManager() (Checker, error)
 }

domain/services/testing/suite.go

@@ -236,7 +236,7 @@ func (s *DomainServicesSuite) SeedModelDatabases(c *gc.C) {
 
 // DomainServicesGetter provides an implementation of the DomainServicesGetter
 // interface to use in tests. This includes the dummy storage registry.
-func (s *DomainServicesSuite) DomainServicesGetter(c *gc.C, objectStore coreobjectstore.ObjectStore, leaseManager lease.LeaseCheckerWaiter) DomainServicesGetterFunc {
+func (s *DomainServicesSuite) DomainServicesGetter(c *gc.C, objectStore coreobjectstore.ObjectStore, leaseManager lease.Checker) DomainServicesGetterFunc {
 	return s.DomainServicesGetterWithStorageRegistry(c, objectStore, leaseManager, storage.ChainedProviderRegistry{
 		// Using the dummy storage provider for testing purposes isn't
 		// ideal. We should potentially use a mock storage provider
@@ -249,7 +249,7 @@ func (s *DomainServicesSuite) DomainServicesGetter(c *gc.C, objectStore coreobje
 // DomainServicesGetterWithStorageRegistry provides an implementation of the
 // DomainServicesGetterWithStorageRegistry interface to use in tests with the
 // additional storage provider.
-func (s *DomainServicesSuite) DomainServicesGetterWithStorageRegistry(c *gc.C, objectStore coreobjectstore.ObjectStore, leaseManager lease.LeaseCheckerWaiter, storageRegistry storage.ProviderRegistry) DomainServicesGetterFunc {
+func (s *DomainServicesSuite) DomainServicesGetterWithStorageRegistry(c *gc.C, objectStore coreobjectstore.ObjectStore, leaseManager lease.Checker, storageRegistry storage.ProviderRegistry) DomainServicesGetterFunc {
 	return func(modelUUID coremodel.UUID) services.DomainServices {
 		return domainservicefactory.NewDomainServices(
 			databasetesting.ConstFactory(s.TxnRunner()),
@@ -264,7 +264,7 @@ func (s *DomainServicesSuite) DomainServicesGetterWithStorageRegistry(c *gc.C, o
 				return storageRegistry, nil
 			}),
 			sshimporter.NewImporter(&http.Client{}),
-			modelApplicationLeaseManagerGetter(func() lease.LeaseCheckerWaiter {
+			modelApplicationLeaseManagerGetter(func() lease.Checker {
 				return leaseManager
 			}),
 			clock.WallClock,
@@ -292,7 +292,7 @@ func (s *DomainServicesSuite) NoopObjectStore(c *gc.C) coreobjectstore.ObjectSto
 }
 
 // NoopLeaseManager returns a no-op implementation of the LeaseCheckerWaiter.
-func (s *DomainServicesSuite) NoopLeaseManager(c *gc.C) lease.LeaseCheckerWaiter {
+func (s *DomainServicesSuite) NoopLeaseManager(c *gc.C) lease.Checker {
 	return TestingLeaseManager{}
 }
 
@@ -345,9 +345,9 @@ func (s modelStorageRegistryGetter) GetStorageRegistry(ctx context.Context) (sto
 	return s(ctx)
 }
 
-type modelApplicationLeaseManagerGetter func() lease.LeaseCheckerWaiter
+type modelApplicationLeaseManagerGetter func() lease.Checker
 
-func (s modelApplicationLeaseManagerGetter) GetLeaseManager() (lease.LeaseCheckerWaiter, error) {
+func (s modelApplicationLeaseManagerGetter) GetLeaseManager() (lease.Checker, error) {
 	return s(), nil
 }
 
@@ -365,7 +365,7 @@ func (TestingObjectStore) Put(ctx context.Context, path string, r io.Reader, siz
 	return "", nil
 }
 
-// Put stores data from reader at path, namespaced to the model.
+// PutAndCheckHash stores data from reader at path, namespaced to the model.
 // It also ensures the stored data has the correct hash.
 func (TestingObjectStore) PutAndCheckHash(ctx context.Context, path string, r io.Reader, size int64, hash string) (objectstore.UUID, error) {
 	return "", nil

internal/worker/domainservices/worker.go

@@ -249,42 +249,14 @@ type modelApplicationLeaseManager struct {
 }
 
 // GetLeaseManager returns a lease manager for the given model UUID.
-func (s modelApplicationLeaseManager) GetLeaseManager() (lease.LeaseCheckerWaiter, error) {
+func (s modelApplicationLeaseManager) GetLeaseManager() (lease.Checker, error) {
 	// TODO (stickupkid): These aren't cheap to make, so we should cache them
 	// and reuse them where possible. I'm not sure these should be workers, I'd
 	// be happy with a sync.Pool at minimum though.
-	claimer, err := s.manager.Claimer(lease.ApplicationLeadershipNamespace, s.modelUUID.String())
-	if err != nil {
-		return nil, internalerrors.Errorf("getting claim lease manager: %w", err)
-	}
-
 	checker, err := s.manager.Checker(lease.ApplicationLeadershipNamespace, s.modelUUID.String())
 	if err != nil {
 		return nil, internalerrors.Errorf("getting checker lease manager: %w", err)
 	}
 
-	return &leaseManager{
-		claimer: claimer,
-		checker: checker,
-	}, nil
-}
-
-type leaseManager struct {
-	claimer lease.Claimer
-	checker lease.Checker
-}
-
-// WaitUntilExpired returns nil when the named lease is no longer held. If
-// it returns any error, no reasonable inferences may be made. The supplied
-// context can be used to cancel the request; in this case, the method will
-// return ErrWaitCancelled.
-// The started channel when non-nil is closed when the wait begins.
-func (m *leaseManager) WaitUntilExpired(ctx context.Context, leaseName string, started chan<- struct{}) error {
-	return m.claimer.WaitUntilExpired(ctx, leaseName, started)
-}
-
-// Token returns a Token that can be interrogated at any time to discover
-// whether the supplied lease is currently held by the supplied holder.
-func (m *leaseManager) Token(leaseName, holderName string) lease.Token {
-	return m.checker.Token(leaseName, holderName)
+	return checker, nil
 }