Documentation
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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 ¶
- Constants
- func Manifold(config ManifoldConfig) dependency.Manifold
- func NewStore(dbGetter database.DBGetter, logger logger.Logger) lease.Store
- func NewWorker(config ManagerConfig) (worker.Worker, error)
- 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 ManifoldConfig
Constants ¶
const ( // MaxSleep is the longest the manager will sleep before checking // whether any leases should be expired. If it can see a lease // expiring sooner than that it will still wake up earlier. MaxSleep = time.Minute )
Variables ¶
This section is empty.
Functions ¶
func Manifold ¶
func Manifold(config ManifoldConfig) dependency.Manifold
Manifold builds a dependency.Manifold for running a lease manager.
func NewWorker ¶
func NewWorker(config ManagerConfig) (worker.Worker, error)
NewWorker wraps NewManager to return worker.Worker for testability.
Types ¶
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 {
// SecretaryFinder determines validation given a namespace. The
// secretary returned is responsible for validating lease names
// and holder names for that namespace.
SecretaryFinder lease.SecretaryFinder
// Store is responsible for recording, retrieving, and expiring leases.
Store lease.Store
// Tracer is used to record tracing information as the manager runs.
Tracer trace.Tracer
// Logger is used to report debugging/status information as the
// manager runs.
Logger 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 ManifoldConfig ¶
type ManifoldConfig struct {
AgentName string
ClockName string
DBAccessorName string
TraceName string
Logger logger.Logger
LogDir string
PrometheusRegisterer prometheus.Registerer
NewWorker func(ManagerConfig) (worker.Worker, error)
NewStore func(database.DBGetter, logger.Logger) lease.Store
NewSecretaryFinder func(string) lease.SecretaryFinder
}
ManifoldConfig holds the resources needed to start the lease manager in a dependency engine.
func (ManifoldConfig) Validate ¶
func (c ManifoldConfig) Validate() error
Validate checks that the config has all the required values.
Source Files