// NewAddresserAPI creates a new server-side Addresser API facade.
func NewAddresserAPI(
	st *state.State,
	resources *common.Resources,
	authorizer common.Authorizer,
) (*AddresserAPI, error) {
	isEnvironManager := authorizer.AuthEnvironManager()
	if !isEnvironManager {
		// Addresser must run as environment manager.
		return nil, common.ErrPerm
	}
	getAuthFunc := func() (common.AuthFunc, error) {
		return func(tag names.Tag) bool {
			return isEnvironManager
		}, nil
	}
	sti := getState(st)
	return &AddresserAPI{
		EnvironWatcher: common.NewEnvironWatcher(sti, resources, authorizer),
		LifeGetter:     common.NewLifeGetter(sti, getAuthFunc),
		Remover:        common.NewRemover(sti, false, getAuthFunc),
		st:             sti,
		resources:      resources,
		authorizer:     authorizer,
	}, nil
}

// NewProvisionerAPI creates a new server-side ProvisionerAPI facade.
func NewProvisionerAPI(st *state.State, resources *common.Resources, authorizer common.Authorizer) (*ProvisionerAPI, error) {
	if !authorizer.AuthMachineAgent() && !authorizer.AuthEnvironManager() {
		return nil, common.ErrPerm
	}
	getAuthFunc := func() (common.AuthFunc, error) {
		isEnvironManager := authorizer.AuthEnvironManager()
		isMachineAgent := authorizer.AuthMachineAgent()
		authEntityTag := authorizer.GetAuthTag()

		return func(tag names.Tag) bool {
			if isMachineAgent && tag == authEntityTag {
				// A machine agent can always access its own machine.
				return true
			}
			switch tag := tag.(type) {
			case names.MachineTag:
				parentId := state.ParentId(tag.Id())
				if parentId == "" {
					// All top-level machines are accessible by the
					// environment manager.
					return isEnvironManager
				}
				// All containers with the authenticated machine as a
				// parent are accessible by it.
				// TODO(dfc) sometimes authEntity tag is nil, which is fine because nil is
				// only equal to nil, but it suggests someone is passing an authorizer
				// with a nil tag.
				return isMachineAgent && names.NewMachineTag(parentId) == authEntityTag
			default:
				return false
			}
		}, nil
	}
	env, err := st.Environment()
	if err != nil {
		return nil, err
	}
	urlGetter := common.NewToolsURLGetter(env.UUID(), st)
	return &ProvisionerAPI{
		Remover:                common.NewRemover(st, false, getAuthFunc),
		StatusSetter:           common.NewStatusSetter(st, getAuthFunc),
		StatusGetter:           common.NewStatusGetter(st, getAuthFunc),
		DeadEnsurer:            common.NewDeadEnsurer(st, getAuthFunc),
		PasswordChanger:        common.NewPasswordChanger(st, getAuthFunc),
		LifeGetter:             common.NewLifeGetter(st, getAuthFunc),
		StateAddresser:         common.NewStateAddresser(st),
		APIAddresser:           common.NewAPIAddresser(st, resources),
		EnvironWatcher:         common.NewEnvironWatcher(st, resources, authorizer),
		EnvironMachinesWatcher: common.NewEnvironMachinesWatcher(st, resources, authorizer),
		InstanceIdGetter:       common.NewInstanceIdGetter(st, getAuthFunc),
		ToolsFinder:            common.NewToolsFinder(st, st, urlGetter),
		st:                     st,
		resources:              resources,
		authorizer:             authorizer,
		getAuthFunc:            getAuthFunc,
	}, nil
}

// NewInstancePollerAPI creates a new server-side InstancePoller API
// facade.
func NewInstancePollerAPI(
	st *state.State,
	resources *common.Resources,
	authorizer common.Authorizer,
) (*InstancePollerAPI, error) {

	if !authorizer.AuthEnvironManager() {
		// InstancePoller must run as environment manager.
		return nil, common.ErrPerm
	}
	accessMachine := common.AuthFuncForTagKind(names.MachineTagKind)
	sti := getState(st)

	// Life() is supported for machines.
	lifeGetter := common.NewLifeGetter(
		sti,
		accessMachine,
	)
	// EnvironConfig() and WatchForEnvironConfigChanges() are allowed
	// with unrestriced access.
	environWatcher := common.NewEnvironWatcher(
		sti,
		resources,
		authorizer,
	)
	// WatchEnvironMachines() is allowed with unrestricted access.
	machinesWatcher := common.NewEnvironMachinesWatcher(
		sti,
		resources,
		authorizer,
	)
	// InstanceId() is supported for machines.
	instanceIdGetter := common.NewInstanceIdGetter(
		sti,
		accessMachine,
	)
	// Status() is supported for machines.
	statusGetter := common.NewStatusGetter(
		sti,
		accessMachine,
	)

	return &InstancePollerAPI{
		LifeGetter:             lifeGetter,
		EnvironWatcher:         environWatcher,
		EnvironMachinesWatcher: machinesWatcher,
		InstanceIdGetter:       instanceIdGetter,
		StatusGetter:           statusGetter,
		st:                     sti,
		resources:              resources,
		authorizer:             authorizer,
		accessMachine:          accessMachine,
	}, nil
}

func (s *environWatcherSuite) TestWatchSuccess(c *gc.C) {
	resources := common.NewResources()
	s.AddCleanup(func(_ *gc.C) { resources.StopAll() })
	e := common.NewEnvironWatcher(
		&fakeEnvironAccessor{},
		resources,
		nil,
	)
	result, err := e.WatchForEnvironConfigChanges()
	c.Assert(err, jc.ErrorIsNil)
	c.Assert(result, gc.DeepEquals, params.NotifyWatchResult{"1", nil})
	c.Assert(resources.Count(), gc.Equals, 1)
}

// NewRsyslogAPI creates a new instance of the Rsyslog API.
func NewRsyslogAPI(st *state.State, resources *common.Resources, authorizer common.Authorizer) (*RsyslogAPI, error) {
	if !authorizer.AuthMachineAgent() && !authorizer.AuthUnitAgent() {
		return nil, common.ErrPerm
	}
	return &RsyslogAPI{
		EnvironWatcher: common.NewEnvironWatcher(st, resources, authorizer),
		st:             st,
		authorizer:     authorizer,
		resources:      resources,
		canModify:      authorizer.AuthEnvironManager(),
		StateAddresser: common.NewStateAddresser(st),
	}, nil
}

func (*environWatcherSuite) TestEnvironConfigFetchError(c *gc.C) {
	authorizer := apiservertesting.FakeAuthorizer{
		Tag:            names.NewMachineTag("0"),
		EnvironManager: true,
	}
	e := common.NewEnvironWatcher(
		&fakeEnvironAccessor{
			envConfigError: fmt.Errorf("pow"),
		},
		nil,
		authorizer,
	)
	_, err := e.EnvironConfig()
	c.Assert(err, gc.ErrorMatches, "pow")
}

func (*environWatcherSuite) TestEnvironConfigSuccess(c *gc.C) {
	authorizer := apiservertesting.FakeAuthorizer{
		Tag:            names.NewMachineTag("0"),
		EnvironManager: true,
	}
	testingEnvConfig := testingEnvConfig(c)
	e := common.NewEnvironWatcher(
		&fakeEnvironAccessor{envConfig: testingEnvConfig},
		nil,
		authorizer,
	)
	result, err := e.EnvironConfig()
	c.Assert(err, jc.ErrorIsNil)
	// Make sure we can read the secret attribute (i.e. it's not masked).
	c.Check(result.Config["secret"], gc.Equals, "pork")
	c.Check(map[string]interface{}(result.Config), jc.DeepEquals, testingEnvConfig.AllAttrs())
}

func (*environWatcherSuite) TestEnvironConfigMaskedSecrets(c *gc.C) {
	authorizer := apiservertesting.FakeAuthorizer{
		Tag:            names.NewMachineTag("0"),
		EnvironManager: false,
	}
	testingEnvConfig := testingEnvConfig(c)
	e := common.NewEnvironWatcher(
		&fakeEnvironAccessor{envConfig: testingEnvConfig},
		nil,
		authorizer,
	)
	result, err := e.EnvironConfig()
	c.Assert(err, jc.ErrorIsNil)
	// Make sure the secret attribute is masked.
	c.Check(result.Config["secret"], gc.Equals, "not available")
	// And only that is masked.
	result.Config["secret"] = "pork"
	c.Check(map[string]interface{}(result.Config), jc.DeepEquals, testingEnvConfig.AllAttrs())
}

// NewUniterAPI creates a new instance of the Uniter API.
func NewUniterAPI(st *state.State, resources *common.Resources, authorizer common.Authorizer) (*UniterAPI, error) {
	if !authorizer.AuthUnitAgent() {
		return nil, common.ErrPerm
	}
	accessUnit := func() (common.AuthFunc, error) {
		return authorizer.AuthOwner, nil
	}
	accessService := func() (common.AuthFunc, error) {
		switch tag := authorizer.GetAuthTag().(type) {
		case names.UnitTag:
			entity, err := st.Unit(tag.Id())
			if err != nil {
				return nil, errors.Trace(err)
			}
			serviceName := entity.ServiceName()
			serviceTag := names.NewServiceTag(serviceName)
			return func(tag names.Tag) bool {
				return tag == serviceTag
			}, nil
		default:
			return nil, errors.Errorf("expected names.UnitTag, got %T", tag)
		}
	}
	accessUnitOrService := common.AuthEither(accessUnit, accessService)

	return &UniterAPI{
		LifeGetter:         common.NewLifeGetter(st, accessUnitOrService),
		StatusSetter:       common.NewStatusSetter(st, accessUnit),
		DeadEnsurer:        common.NewDeadEnsurer(st, accessUnit),
		AgentEntityWatcher: common.NewAgentEntityWatcher(st, resources, accessUnitOrService),
		APIAddresser:       common.NewAPIAddresser(st, resources),
		EnvironWatcher:     common.NewEnvironWatcher(st, resources, authorizer),

		st:            st,
		auth:          authorizer,
		resources:     resources,
		accessUnit:    accessUnit,
		accessService: accessService,
	}, nil
}

// newUniterBaseAPI creates a new instance of the uniter base API.
func newUniterBaseAPI(st *state.State, resources *common.Resources, authorizer common.Authorizer) (*uniterBaseAPI, error) {
	if !authorizer.AuthUnitAgent() {
		return nil, common.ErrPerm
	}
	var unit *state.Unit
	var err error
	switch tag := authorizer.GetAuthTag().(type) {
	case names.UnitTag:
		unit, err = st.Unit(tag.Id())
		if err != nil {
			return nil, errors.Trace(err)
		}
	default:
		return nil, errors.Errorf("expected names.UnitTag, got %T", tag)
	}
	accessUnit := func() (common.AuthFunc, error) {
		return authorizer.AuthOwner, nil
	}
	accessService := func() (common.AuthFunc, error) {
		switch tag := authorizer.GetAuthTag().(type) {
		case names.UnitTag:
			entity, err := st.Unit(tag.Id())
			if err != nil {
				return nil, errors.Trace(err)
			}
			serviceName := entity.ServiceName()
			serviceTag := names.NewServiceTag(serviceName)
			return func(tag names.Tag) bool {
				return tag == serviceTag
			}, nil
		default:
			return nil, errors.Errorf("expected names.UnitTag, got %T", tag)
		}
	}
	accessMachine := func() (common.AuthFunc, error) {
		machineId, err := unit.AssignedMachineId()
		if err != nil {
			return nil, errors.Trace(err)
		}
		machine, err := st.Machine(machineId)
		if err != nil {
			return nil, errors.Trace(err)
		}
		return func(tag names.Tag) bool {
			return tag == machine.Tag()
		}, nil
	}
	msAPI, err := meterstatus.NewMeterStatusAPI(st, resources, authorizer)
	if err != nil {
		return nil, errors.Annotate(err, "could not create meter status API handler")
	}
	accessUnitOrService := common.AuthEither(accessUnit, accessService)
	return &uniterBaseAPI{
		LifeGetter:                 common.NewLifeGetter(st, accessUnitOrService),
		DeadEnsurer:                common.NewDeadEnsurer(st, accessUnit),
		AgentEntityWatcher:         common.NewAgentEntityWatcher(st, resources, accessUnitOrService),
		APIAddresser:               common.NewAPIAddresser(st, resources),
		EnvironWatcher:             common.NewEnvironWatcher(st, resources, authorizer),
		RebootRequester:            common.NewRebootRequester(st, accessMachine),
		LeadershipSettingsAccessor: leadershipSettingsAccessorFactory(st, resources, authorizer),
		MeterStatus:                msAPI,
		// TODO(fwereade): so *every* unit should be allowed to get/set its
		// own status *and* its service's? This is not a pleasing arrangement.
		StatusAPI: NewStatusAPI(st, accessUnitOrService),

		st:            st,
		auth:          authorizer,
		resources:     resources,
		accessUnit:    accessUnit,
		accessService: accessService,
		unit:          unit,
	}, nil
}

//.........这里部分代码省略.........
				return canAccessStorageMachine(tag, false)
			default:
				return false
			}
		}, nil
	}
	canAccessStorageEntity := func(tag names.Tag, allowMachines bool) bool {
		switch tag := tag.(type) {
		case names.VolumeTag:
			machineTag, ok := names.VolumeMachine(tag)
			if ok {
				return canAccessStorageMachine(machineTag, false)
			}
			return authorizer.AuthEnvironManager()
		case names.FilesystemTag:
			machineTag, ok := names.FilesystemMachine(tag)
			if ok {
				return canAccessStorageMachine(machineTag, false)
			}
			return authorizer.AuthEnvironManager()
		case names.MachineTag:
			return allowMachines && canAccessStorageMachine(tag, true)
		default:
			return false
		}
	}
	getStorageEntityAuthFunc := func() (common.AuthFunc, error) {
		return func(tag names.Tag) bool {
			return canAccessStorageEntity(tag, false)
		}, nil
	}
	getLifeAuthFunc := func() (common.AuthFunc, error) {
		return func(tag names.Tag) bool {
			return canAccessStorageEntity(tag, true)
		}, nil
	}
	getAttachmentAuthFunc := func() (func(names.MachineTag, names.Tag) bool, error) {
		// getAttachmentAuthFunc returns a function that validates
		// access by the authenticated user to an attachment.
		return func(machineTag names.MachineTag, attachmentTag names.Tag) bool {
			// Machine agents can access their own machine, and
			// machines contained. Environment managers can access
			// top-level machines.
			if !canAccessStorageMachine(machineTag, true) {
				return false
			}
			// Environment managers can access environment-scoped
			// volumes and volumes scoped to their own machines.
			// Other machine agents can access volumes regardless
			// of their scope.
			if !authorizer.AuthEnvironManager() {
				return true
			}
			var machineScope names.MachineTag
			var hasMachineScope bool
			switch attachmentTag := attachmentTag.(type) {
			case names.VolumeTag:
				machineScope, hasMachineScope = names.VolumeMachine(attachmentTag)
			case names.FilesystemTag:
				machineScope, hasMachineScope = names.FilesystemMachine(attachmentTag)
			}
			return !hasMachineScope || machineScope == authorizer.GetAuthTag()
		}, nil
	}
	getMachineAuthFunc := func() (common.AuthFunc, error) {
		return func(tag names.Tag) bool {
			if tag, ok := tag.(names.MachineTag); ok {
				return canAccessStorageMachine(tag, true)
			}
			return false
		}, nil
	}
	getBlockDevicesAuthFunc := func() (common.AuthFunc, error) {
		return func(tag names.Tag) bool {
			if tag, ok := tag.(names.MachineTag); ok {
				return canAccessStorageMachine(tag, false)
			}
			return false
		}, nil
	}
	stateInterface := getState(st)
	settings := getSettingsManager(st)
	return &StorageProvisionerAPI{
		LifeGetter:       common.NewLifeGetter(stateInterface, getLifeAuthFunc),
		DeadEnsurer:      common.NewDeadEnsurer(stateInterface, getStorageEntityAuthFunc),
		EnvironWatcher:   common.NewEnvironWatcher(stateInterface, resources, authorizer),
		InstanceIdGetter: common.NewInstanceIdGetter(st, getMachineAuthFunc),
		StatusSetter:     common.NewStatusSetter(st, getStorageEntityAuthFunc),

		st:                       stateInterface,
		settings:                 settings,
		resources:                resources,
		authorizer:               authorizer,
		getScopeAuthFunc:         getScopeAuthFunc,
		getStorageEntityAuthFunc: getStorageEntityAuthFunc,
		getAttachmentAuthFunc:    getAttachmentAuthFunc,
		getMachineAuthFunc:       getMachineAuthFunc,
		getBlockDevicesAuthFunc:  getBlockDevicesAuthFunc,
	}, nil
}

// NewEnvironmentAPI creates a new instance of the Environment API.
func NewEnvironmentAPI(st *state.State, resources *common.Resources, authorizer common.Authorizer) (*EnvironmentAPI, error) {
	return &EnvironmentAPI{
		EnvironWatcher: common.NewEnvironWatcher(st, resources, authorizer),
		EnvironTools:   NewEnvironTools(st, authorizer),
	}, nil
}

// newUniterBaseAPI creates a new instance of the uniter base API.
func newUniterBaseAPI(st *state.State, resources *common.Resources, authorizer common.Authorizer) (*uniterBaseAPI, error) {
	if !authorizer.AuthUnitAgent() {
		return nil, common.ErrPerm
	}
	var unit *state.Unit
	var err error
	switch tag := authorizer.GetAuthTag().(type) {
	case names.UnitTag:
		unit, err = st.Unit(tag.Id())
		if err != nil {
			return nil, errors.Trace(err)
		}
	default:
		return nil, errors.Errorf("expected names.UnitTag, got %T", tag)
	}
	accessUnit := func() (common.AuthFunc, error) {
		return authorizer.AuthOwner, nil
	}
	accessService := func() (common.AuthFunc, error) {
		switch tag := authorizer.GetAuthTag().(type) {
		case names.UnitTag:
			entity, err := st.Unit(tag.Id())
			if err != nil {
				return nil, errors.Trace(err)
			}
			serviceName := entity.ServiceName()
			serviceTag := names.NewServiceTag(serviceName)
			return func(tag names.Tag) bool {
				return tag == serviceTag
			}, nil
		default:
			return nil, errors.Errorf("expected names.UnitTag, got %T", tag)
		}
	}
	accessMachine := func() (common.AuthFunc, error) {
		machineId, err := unit.AssignedMachineId()
		if err != nil {
			return nil, errors.Trace(err)
		}
		machine, err := st.Machine(machineId)
		if err != nil {
			return nil, errors.Trace(err)
		}
		return func(tag names.Tag) bool {
			return tag == machine.Tag()
		}, nil
	}

	accessUnitOrService := common.AuthEither(accessUnit, accessService)
	return &uniterBaseAPI{
		LifeGetter:                 common.NewLifeGetter(st, accessUnitOrService),
		StatusAPI:                  NewStatusAPI(st, accessUnitOrService),
		DeadEnsurer:                common.NewDeadEnsurer(st, accessUnit),
		AgentEntityWatcher:         common.NewAgentEntityWatcher(st, resources, accessUnitOrService),
		APIAddresser:               common.NewAPIAddresser(st, resources),
		EnvironWatcher:             common.NewEnvironWatcher(st, resources, authorizer),
		RebootRequester:            common.NewRebootRequester(st, accessMachine),
		LeadershipSettingsAccessor: leadershipSettingsAccessorFactory(st, resources, authorizer),

		st:            st,
		auth:          authorizer,
		resources:     resources,
		accessUnit:    accessUnit,
		accessService: accessService,
		unit:          unit,
	}, nil
}

// NewFirewallerAPI creates a new server-side FirewallerAPI facade.
func NewFirewallerAPI(
	st *state.State,
	resources *common.Resources,
	authorizer common.Authorizer,
) (*FirewallerAPI, error) {
	if !authorizer.AuthEnvironManager() {
		// Firewaller must run as environment manager.
		return nil, common.ErrPerm
	}
	// Set up the various authorization checkers.
	accessEnviron := common.AuthFuncForTagKind(names.EnvironTagKind)
	accessUnit := common.AuthFuncForTagKind(names.UnitTagKind)
	accessService := common.AuthFuncForTagKind(names.ServiceTagKind)
	accessMachine := common.AuthFuncForTagKind(names.MachineTagKind)
	accessUnitOrService := common.AuthEither(accessUnit, accessService)
	accessUnitServiceOrMachine := common.AuthEither(accessUnitOrService, accessMachine)

	// Life() is supported for units, services or machines.
	lifeGetter := common.NewLifeGetter(
		st,
		accessUnitServiceOrMachine,
	)
	// EnvironConfig() and WatchForEnvironConfigChanges() are allowed
	// with unrestriced access.
	environWatcher := common.NewEnvironWatcher(
		st,
		resources,
		authorizer,
	)
	// Watch() is supported for services only.
	entityWatcher := common.NewAgentEntityWatcher(
		st,
		resources,
		accessService,
	)
	// WatchUnits() is supported for machines.
	unitsWatcher := common.NewUnitsWatcher(st,
		resources,
		accessMachine,
	)
	// WatchEnvironMachines() is allowed with unrestricted access.
	machinesWatcher := common.NewEnvironMachinesWatcher(
		st,
		resources,
		authorizer,
	)
	// InstanceId() is supported for machines.
	instanceIdGetter := common.NewInstanceIdGetter(
		st,
		accessMachine,
	)

	return &FirewallerAPI{
		LifeGetter:             lifeGetter,
		EnvironWatcher:         environWatcher,
		AgentEntityWatcher:     entityWatcher,
		UnitsWatcher:           unitsWatcher,
		EnvironMachinesWatcher: machinesWatcher,
		InstanceIdGetter:       instanceIdGetter,
		st:                     st,
		resources:              resources,
		authorizer:             authorizer,
		accessUnit:             accessUnit,
		accessService:          accessService,
		accessMachine:          accessMachine,
		accessEnviron:          accessEnviron,
	}, nil
}