Documentation
¶
Overview ¶
Package lease, also known as the manager, manages the leases used by individual Juju workers.
Workers will claim a lease, and they are either attributed (i.e., the workers gets the lease ) or blocked (i.e., the worker is waiting for a lease to become available). In the latter case, the manager will keep track of all the blocked claims. When a worker's lease expires or gets revoked, then the manager will re-attribute it to one of other workers, thus unblocking them and satisfying their claim. In the special case where a worker is upgrading an application, it will ask the manager to "pin" the lease. This means that the lease will not expire or be revoked during the upgrade, and the validity of the lease will get refreshed once the upgrade has completed. The overall effect is that the application unit does not lose leadership during an upgrade.
Index ¶
- func SecretaryFinder(controllerUUID string) func(string) (Secretary, error)
- type LeadershipSecretary
- type Logger
- type Manager
- func (manager *Manager) Checker(namespace, modelUUID string) (lease.Checker, error)
- func (manager *Manager) Claimer(namespace, modelUUID string) (lease.Claimer, error)
- func (manager *Manager) Kill()
- func (manager *Manager) Pinner(namespace, modelUUID string) (lease.Pinner, error)
- func (manager *Manager) Reader(namespace, modelUUID string) (lease.Reader, error)
- func (manager *Manager) Report() map[string]interface{}
- func (manager *Manager) Revoker(namespace, modelUUID string) (lease.Revoker, error)
- func (manager *Manager) Wait() error
- type ManagerConfig
- type Secretary
- type SingularSecretary
- type Store
- func (s *Store) ClaimLease(ctx context.Context, key lease.Key, req lease.Request) error
- func (s *Store) ExtendLease(ctx context.Context, key lease.Key, req lease.Request) error
- func (s *Store) LeaseGroup(ctx context.Context, namespace, modelUUID string) (map[lease.Key]lease.Info, error)
- func (s *Store) Leases(ctx context.Context, keys ...lease.Key) (map[lease.Key]lease.Info, error)
- func (s *Store) PinLease(ctx context.Context, key lease.Key, entity string) error
- func (s *Store) Pinned(ctx context.Context) (map[lease.Key][]string, error)
- func (s *Store) RevokeLease(ctx context.Context, key lease.Key, holder string) error
- func (s *Store) UnpinLease(ctx context.Context, key lease.Key, entity string) error
- type StoreConfig
- type StoreLogger
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
Types ¶
type LeadershipSecretary ¶
type LeadershipSecretary struct{}
LeadershipSecretary implements Secretary; it checks that leases are application names, and holders are unit names.
func (LeadershipSecretary) CheckDuration ¶
func (LeadershipSecretary) CheckDuration(duration time.Duration) error
CheckDuration is part of the lease.Secretary interface.
func (LeadershipSecretary) CheckHolder ¶
func (LeadershipSecretary) CheckHolder(name string) error
CheckHolder is part of the lease.Secretary interface.
func (LeadershipSecretary) CheckLease ¶
func (LeadershipSecretary) CheckLease(key lease.Key) error
CheckLease is part of the lease.Secretary interface.
type Logger ¶
type Logger interface {
Tracef(string, ...interface{})
Debugf(string, ...interface{})
Infof(string, ...interface{})
Warningf(string, ...interface{})
Errorf(string, ...interface{})
}
Logger represents the logging methods we use from a loggo.Logger.
type Manager ¶
type Manager struct {
// contains filtered or unexported fields
}
Manager implements worker.Worker and can be bound to get lease.Checkers and lease.Claimers.
func NewManager ¶
func NewManager(config ManagerConfig) (*Manager, error)
NewManager returns a new *Manager configured as supplied. The caller takes responsibility for killing, and handling errors from, the returned Worker.
type ManagerConfig ¶
type ManagerConfig struct {
// Secretary determines validation given a namespace. The
// secretary returned is responsible for validating lease names
// and holder names for that namespace.
Secretary func(namespace string) (Secretary, error)
// Store is responsible for recording, retrieving, and expiring leases.
Store lease.Store
// Logger is used to report debugging/status information as the
// manager runs.
Logger Logger
// Clock is responsible for reporting the passage of time.
Clock clock.Clock
// MaxSleep is the longest time the Manager should sleep before
// refreshing its store's leases and checking for expiries.
MaxSleep time.Duration
// EntityUUID is the entity that we are running this Manager for. Used for
// logging purposes.
EntityUUID string
// LogDir is the directory to write a debugging log file in the
// case that the worker times out waiting to shut down.
LogDir string
PrometheusRegisterer prometheus.Registerer
}
ManagerConfig contains the resources and information required to create a Manager.
func (ManagerConfig) Validate ¶
func (config ManagerConfig) Validate() error
Validate returns an error if the configuration contains invalid information or missing resources.
type Secretary ¶
type Secretary interface {
// CheckLease returns an error if the supplied lease name is not valid.
CheckLease(key lease.Key) error
// CheckHolder returns an error if the supplied holder name is not valid.
CheckHolder(name string) error
// CheckDuration returns an error if the supplied duration is not valid.
CheckDuration(duration time.Duration) error
}
Secretary is responsible for validating the sanity of lease and holder names before bothering the manager with them.
type SingularSecretary ¶
type SingularSecretary struct {
ControllerUUID string
}
SingularSecretary implements Secretary to restrict claims to either a lease for the controller or the specific model it's asking for, holdable only by machine-tag strings.
func (SingularSecretary) CheckDuration ¶
func (s SingularSecretary) CheckDuration(duration time.Duration) error
CheckDuration is part of the lease.Secretary interface.
func (SingularSecretary) CheckHolder ¶
func (s SingularSecretary) CheckHolder(name string) error
CheckHolder is part of the lease.Secretary interface.
func (SingularSecretary) CheckLease ¶
func (s SingularSecretary) CheckLease(key lease.Key) error
CheckLease is part of the lease.Secretary interface.
type Store ¶
type Store struct {
// contains filtered or unexported fields
}
Store implements lease.Store using a database supporting SQLite-compatible dialects.
func NewStore ¶
func NewStore(cfg StoreConfig) *Store
NewStore returns a reference to a new database-backed lease store.
func (*Store) ClaimLease ¶
ClaimLease (lease.Store) claims the lease indicated by the input key, for the holder and duration indicated by the input request. The lease must not already be held, otherwise an error is returned.
func (*Store) ExtendLease ¶
ExtendLease (lease.Store) ensures the input lease will be held for at least the requested duration starting from now. If the input holder does not currently hold the lease, an error is returned.
func (*Store) LeaseGroup ¶
func (s *Store) LeaseGroup(ctx context.Context, namespace, modelUUID string) (map[lease.Key]lease.Info, error)
LeaseGroup (lease.Store) returns all leases for the input namespace and model.
func (*Store) Leases ¶
Leases (lease.Store) returns all leases in the database, optionally filtering using the input keys.
func (*Store) PinLease ¶
PinLease (lease.Store) adds the input entity into the lease_pin table to indicate that the lease indicated by the input key must not expire, and that this entity requires such behaviour.
func (*Store) Pinned ¶
Pinned (lease.Store) returns all leases that are currently pinned, and the entities requiring such behaviour for them.
func (*Store) RevokeLease ¶
RevokeLease (lease.Store) deletes the lease from the store, provided it exists and is held by the input holder. If either of these conditions is false, an error is returned.
func (*Store) UnpinLease ¶
UnpinLease (lease.Store) removes the record indicated by the input key and entity from the lease pin table, indicating that the entity no longer requires the lease to be pinned. When there are no entities associated with a particular lease, it is determined not to be pinned, and can expire normally.
type StoreConfig ¶
type StoreConfig struct {
// TrackedDB is the SQL database that backs this lease store.
TrackedDB coredatabase.TrackedDB
// Logger is used to emit store-specific diagnostics.
Logger StoreLogger
}
StoreConfig encapsulates data required to construct a lease store instance.
type StoreLogger ¶
type StoreLogger interface {
Errorf(string, ...interface{})
}
StoreLogger describes methods for logging lease store concerns.
Source Files
Directories