storage

Documentation

Overview

Package storage contains the storage subsystem for the uniter, responding to changes in storage attachments (lifecycle, volume/filesystem details) by queuing hooks and managing the storage attachments' lifecycle.

Index

• func NewResolver(logger Logger, storage *Attachments, modelType model.ModelType) resolver.Resolver
• func NewStateOps(rw UnitStateReadWriter) *stateOps
• type Attachments
  • func NewAttachments(st StorageAccessor, tag names.UnitTag, rw UnitStateReadWriter, ...) (*Attachments, error)
  • func (a *Attachments) CommitHook(hi hook.Info) error
  • func (a *Attachments) Pending() int
  • func (a *Attachments) SetDying() error
  • func (a *Attachments) ValidateHook(hi hook.Info) error
• type Logger
• type State
  • func NewState() *State
  • func (s *State) Attach(storageID string)
  • func (s *State) Attached(storageID string) (bool, bool)
  • func (s *State) Detach(storageID string) error
  • func (s *State) Empty() bool
  • func (s *State) ValidateHook(hi hook.Info) (err error)
• type StorageAccessor
• type StorageResolverOperations
• type UnitStateReadWriter

Functions

func NewResolver

func NewResolver(logger Logger, storage *Attachments, modelType model.ModelType) resolver.Resolver

NewResolver returns a new storage resolver.

func NewStateOps

func NewStateOps(rw UnitStateReadWriter) *stateOps

NewStateOps returns a new StateOps.

Types

type Attachments

type Attachments struct {
	// contains filtered or unexported fields
}

Attachments generates storage hooks in response to changes to storage attachments.

func NewAttachments

func NewAttachments(
	st StorageAccessor,
	tag names.UnitTag,
	rw UnitStateReadWriter,
	abort <-chan struct{},
) (*Attachments, error)

NewAttachments returns a new Attachments.

func (*Attachments) CommitHook

func (a *Attachments) CommitHook(hi hook.Info) error

CommitHook persists the State change encoded in the supplied storage hook, or returns an error if the hook is invalid given current State.

func (*Attachments) Pending

func (a *Attachments) Pending() int

Pending reports the number of storage attachments whose hooks have yet to be run and committed.

func (*Attachments) SetDying

func (a *Attachments) SetDying() error

SetDying ensures that any unprovisioned storage attachments are removed from State.

func (*Attachments) ValidateHook

func (a *Attachments) ValidateHook(hi hook.Info) error

ValidateHook validates the hook against the current State.

type Logger

type Logger interface {
	Infof(string, ...interface{})
	Debugf(string, ...interface{})
}

Logger represents the logging methods used in this package.

type State

type State struct {
	// contains filtered or unexported fields
}

State describes the State of storage attachments.

func NewState

func NewState() *State

func (*State) Attach

func (s *State) Attach(storageID string)

func (*State) Attached

func (s *State) Attached(storageID string) (bool, bool)

func (*State) Detach

func (s *State) Detach(storageID string) error

func (*State) Empty

func (s *State) Empty() bool

func (*State) ValidateHook

func (s *State) ValidateHook(hi hook.Info) (err error)

ValidateHook returns an error if the supplied hook.Info does not represent a valid change to the storage State. Hooks must always be validated against the current State before they are run, to ensure that the system meets its guarantees about hook execution order.

type StorageAccessor

type StorageAccessor interface {
	// StorageAttachment returns details of the storage attachment
	// with the specified unit and storage tags.
	StorageAttachment(names.StorageTag, names.UnitTag) (params.StorageAttachment, error)

	// UnitStorageAttachments returns details of all of the storage
	// attachments for the unit with the specified tag.
	UnitStorageAttachments(names.UnitTag) ([]params.StorageAttachmentId, error)

	// DestroyUnitStorageAttachments ensures that all storage
	// attachments for the specified unit will be removed at
	// some point in the future.
	DestroyUnitStorageAttachments(names.UnitTag) error

	// RemoveStorageAttachment removes that the storage attachment
	// with the specified unit and storage tags. This method is only
	// expected to succeed if the storage attachment is Dying.
	RemoveStorageAttachment(names.StorageTag, names.UnitTag) error
}

StorageAccessor is an interface for accessing information about storage attachments.

type StorageResolverOperations

type StorageResolverOperations interface {
	NewUpdateStorage(tags []names.StorageTag) (operation.Operation, error)
	NewRunHook(hookInfo hook.Info) (operation.Operation, error)
}

StorageResolverOperations instances know how to make operations required by the resolver.

type UnitStateReadWriter

type UnitStateReadWriter interface {
	State() (params.UnitStateResult, error)
	SetState(unitState params.SetUnitStateArg) error
}

UnitStateReadWriter encapsulates the methods from a state.Unit required to set and get unit state.