func (st *State) createDefaultStoragePoolsOps(registry storage.ProviderRegistry) ([]txn.Op, error) {
	m := poolmanager.MemSettings{make(map[string]map[string]interface{})}
	pm := poolmanager.New(m, registry)
	providerTypes, err := registry.StorageProviderTypes()
	if err != nil {
		return nil, errors.Trace(err)
	}
	for _, providerType := range providerTypes {
		p, err := registry.StorageProvider(providerType)
		if err != nil {
			return nil, errors.Trace(err)
		}
		if err := poolmanager.AddDefaultStoragePools(p, pm); err != nil {
			return nil, errors.Annotatef(
				err, "adding default storage pools for %q", providerType,
			)
		}
	}

	var ops []txn.Op
	for key, settings := range m.Settings {
		ops = append(ops, createSettingsOp(settingsC, key, settings))
	}
	return ops, nil
}

func (s *VolumeStateSuite) TestAddServiceDefaultPool(c *gc.C) {
	// Register a default pool.
	pm := poolmanager.New(state.NewStateSettings(s.State))
	_, err := pm.Create("default-block", provider.LoopProviderType, map[string]interface{}{})
	c.Assert(err, jc.ErrorIsNil)
	err = s.State.UpdateEnvironConfig(map[string]interface{}{
		"storage-default-block-source": "default-block",
	}, nil, nil)
	c.Assert(err, jc.ErrorIsNil)

	ch := s.AddTestingCharm(c, "storage-block")
	storage := map[string]state.StorageConstraints{
		"data": makeStorageCons("", 1024, 1),
	}
	service := s.AddTestingServiceWithStorage(c, "storage-block", ch, storage)
	cons, err := service.StorageConstraints()
	c.Assert(err, jc.ErrorIsNil)
	c.Assert(cons, jc.DeepEquals, map[string]state.StorageConstraints{
		"data": state.StorageConstraints{
			Pool:  "default-block",
			Size:  1024,
			Count: 1,
		},
		"allecto": state.StorageConstraints{
			Pool:  "loop",
			Size:  1024,
			Count: 0,
		},
	})
}

func poolStorageProvider(st *State, poolName string) (storage.ProviderType, storage.Provider, error) {
	registry, err := st.storageProviderRegistry()
	if err != nil {
		return "", nil, errors.Annotate(err, "getting storage provider registry")
	}
	poolManager := poolmanager.New(NewStateSettings(st), registry)
	pool, err := poolManager.Get(poolName)
	if errors.IsNotFound(err) {
		// If there's no pool called poolName, maybe a provider type
		// has been specified directly.
		providerType := storage.ProviderType(poolName)
		provider, err1 := registry.StorageProvider(providerType)
		if err1 != nil {
			// The name can't be resolved as a storage provider type,
			// so return the original "pool not found" error.
			return "", nil, errors.Trace(err)
		}
		return providerType, provider, nil
	} else if err != nil {
		return "", nil, errors.Trace(err)
	}
	providerType := pool.Provider()
	provider, err := registry.StorageProvider(providerType)
	if err != nil {
		return "", nil, errors.Trace(err)
	}
	return providerType, provider, nil
}

// machineVolumeParams retrieves VolumeParams for the volumes that should be
// provisioned with, and attached to, the machine. The client should ignore
// parameters that it does not know how to handle.
func (p *ProvisionerAPI) machineVolumeParams(m *state.Machine) ([]params.VolumeParams, error) {
	volumeAttachments, err := m.VolumeAttachments()
	if err != nil {
		return nil, err
	}
	if len(volumeAttachments) == 0 {
		return nil, nil
	}
	envConfig, err := p.st.EnvironConfig()
	if err != nil {
		return nil, err
	}
	poolManager := poolmanager.New(state.NewStateSettings(p.st))
	allVolumeParams := make([]params.VolumeParams, 0, len(volumeAttachments))
	for _, volumeAttachment := range volumeAttachments {
		volumeTag := volumeAttachment.Volume()
		volume, err := p.st.Volume(volumeTag)
		if err != nil {
			return nil, errors.Annotatef(err, "getting volume %q", volumeTag.Id())
		}
		storageInstance, err := storagecommon.MaybeAssignedStorageInstance(
			volume.StorageInstance, p.st.StorageInstance,
		)
		if err != nil {
			return nil, errors.Annotatef(err, "getting volume %q storage instance", volumeTag.Id())
		}
		volumeParams, err := storagecommon.VolumeParams(volume, storageInstance, envConfig, poolManager)
		if err != nil {
			return nil, errors.Annotatef(err, "getting volume %q parameters", volumeTag.Id())
		}
		provider, err := registry.StorageProvider(storage.ProviderType(volumeParams.Provider))
		if err != nil {
			return nil, errors.Annotate(err, "getting storage provider")
		}
		if provider.Dynamic() {
			// Leave dynamic storage to the storage provisioner.
			continue
		}
		volumeAttachmentParams, ok := volumeAttachment.Params()
		if !ok {
			// Attachment is already provisioned; this is an insane
			// state, so we should not proceed with the volume.
			return nil, errors.Errorf(
				"volume %s already attached to machine %s",
				volumeTag.Id(), m.Id(),
			)
		}
		// Not provisioned yet, so ask the cloud provisioner do it.
		volumeParams.Attachment = &params.VolumeAttachmentParams{
			volumeTag.String(),
			m.Tag().String(),
			"", // we're creating the volume, so it has no volume ID.
			"", // we're creating the machine, so it has no instance ID.
			volumeParams.Provider,
			volumeAttachmentParams.ReadOnly,
		}
		allVolumeParams = append(allVolumeParams, volumeParams)
	}
	return allVolumeParams, nil
}

func (s *serviceSuite) TestClientServiceDeployWithUnsupportedStoragePool(c *gc.C) {
	registry.RegisterProvider("hostloop", &mockStorageProvider{kind: storage.StorageKindBlock})
	pm := poolmanager.New(state.NewStateSettings(s.State))
	_, err := pm.Create("host-loop-pool", provider.HostLoopProviderType, map[string]interface{}{})
	c.Assert(err, jc.ErrorIsNil)

	curl, _ := s.UploadCharm(c, "utopic/storage-block-0", "storage-block")
	storageConstraints := map[string]storage.Constraints{
		"data": storage.Constraints{
			Pool:  "host-loop-pool",
			Count: 1,
			Size:  1024,
		},
	}

	var cons constraints.Value
	args := params.ServiceDeploy{
		ServiceName: "service",
		CharmUrl:    curl.String(),
		NumUnits:    1,
		Constraints: cons,
		Storage:     storageConstraints,
	}
	results, err := s.serviceApi.ServicesDeploy(params.ServicesDeploy{
		Services: []params.ServiceDeploy{args}},
	)
	c.Assert(err, jc.ErrorIsNil)
	c.Assert(results.Results, gc.HasLen, 1)
	c.Assert(results.Results[0].Error, gc.ErrorMatches,
		`.*pool "host-loop-pool" uses storage provider "hostloop" which is not supported for environments of type "dummy"`)
}

func (s *EnvironSuite) TestDestroyEnvironmentWithPersistentVolumesFails(c *gc.C) {
	// Create a persistent volume.
	// TODO(wallyworld) - consider moving this to factory
	registry.RegisterEnvironStorageProviders("someprovider", ec2.EBS_ProviderType)
	pm := poolmanager.New(state.NewStateSettings(s.State))
	_, err := pm.Create("persistent-block", ec2.EBS_ProviderType, map[string]interface{}{"persistent": "true"})
	c.Assert(err, jc.ErrorIsNil)

	ch := s.AddTestingCharm(c, "storage-block2")
	storage := map[string]state.StorageConstraints{
		"multi1to10": makeStorageCons("persistent-block", 1024, 1),
	}
	service := s.AddTestingServiceWithStorage(c, "storage-block2", ch, storage)
	unit, err := service.AddUnit()
	c.Assert(err, jc.ErrorIsNil)
	err = s.State.AssignUnit(unit, state.AssignCleanEmpty)
	c.Assert(err, jc.ErrorIsNil)

	volume1, err := s.State.StorageInstanceVolume(names.NewStorageTag("multi1to10/0"))
	c.Assert(err, jc.ErrorIsNil)
	volumeInfoSet := state.VolumeInfo{Size: 123, Persistent: true, VolumeId: "vol-ume"}
	err = s.State.SetVolumeInfo(volume1.VolumeTag(), volumeInfoSet)
	c.Assert(err, jc.ErrorIsNil)

	env, err := s.State.Environment()
	c.Assert(err, jc.ErrorIsNil)
	// TODO(wallyworld) when we can destroy/remove volume, ensure env can then be destroyed
	c.Assert(errors.Cause(env.Destroy()), gc.Equals, state.ErrPersistentVolumesExist)
}

// TODO(wallyworld) - add another test that deploy with storage fails for older environments
// (need deploy client to be refactored to use API stub)
func (s *DeploySuite) TestStorage(c *gc.C) {
	pm := poolmanager.New(state.NewStateSettings(s.State))
	_, err := pm.Create("loop-pool", provider.LoopProviderType, map[string]interface{}{"foo": "bar"})
	c.Assert(err, jc.ErrorIsNil)

	testcharms.Repo.CharmArchivePath(s.SeriesPath, "storage-block")
	err = runDeploy(c, "local:storage-block", "--storage", "data=loop-pool,1G")
	c.Assert(err, jc.ErrorIsNil)
	curl := charm.MustParseURL("local:trusty/storage-block-1")
	service, _ := s.AssertService(c, "storage-block", curl, 1, 0)

	cons, err := service.StorageConstraints()
	c.Assert(err, jc.ErrorIsNil)
	c.Assert(cons, jc.DeepEquals, map[string]state.StorageConstraints{
		"data": {
			Pool:  "loop-pool",
			Count: 1,
			Size:  1024,
		},
		"allecto": {
			Pool:  "loop",
			Count: 0,
			Size:  1024,
		},
	})
}

func (s *MigrationBaseSuite) makeUnitWithStorage(c *gc.C) (*state.Application, *state.Unit, names.StorageTag) {
	pool := "loop-pool"
	kind := "block"
	// Create a default pool for block devices.
	pm := poolmanager.New(state.NewStateSettings(s.State), dummy.StorageProviders())
	_, err := pm.Create(pool, provider.LoopProviderType, map[string]interface{}{})
	c.Assert(err, jc.ErrorIsNil)

	// There are test charms called "storage-block" and
	// "storage-filesystem" which are what you'd expect.
	ch := s.AddTestingCharm(c, "storage-"+kind)
	storage := map[string]state.StorageConstraints{
		"data": makeStorageCons(pool, 1024, 1),
	}
	service := s.AddTestingServiceWithStorage(c, "storage-"+kind, ch, storage)
	unit, err := service.AddUnit()

	machine := s.Factory.MakeMachine(c, nil)
	err = unit.AssignToMachine(machine)
	c.Assert(err, jc.ErrorIsNil)

	c.Assert(err, jc.ErrorIsNil)
	storageTag := names.NewStorageTag("data/0")
	agentVersion := version.MustParseBinary("2.0.1-quantal-and64")
	err = unit.SetAgentVersion(agentVersion)
	c.Assert(err, jc.ErrorIsNil)
	return service, unit, storageTag
}

func setupTestStorageSupport(c *gc.C, s *state.State) {
	stsetts := state.NewStateSettings(s)
	poolManager := poolmanager.New(stsetts, dummy.StorageProviders())
	_, err := poolManager.Create(testPool, provider.LoopProviderType, map[string]interface{}{"it": "works"})
	c.Assert(err, jc.ErrorIsNil)
	_, err = poolManager.Create(testPersistentPool, "environscoped", map[string]interface{}{"persistent": true})
	c.Assert(err, jc.ErrorIsNil)
}

func setupTestStorageSupport(c *gc.C, s *state.State) {
	stsetts := state.NewStateSettings(s)
	poolManager := poolmanager.New(stsetts)
	_, err := poolManager.Create(testPool, provider.LoopProviderType, map[string]interface{}{"it": "works"})
	c.Assert(err, jc.ErrorIsNil)

	registry.RegisterEnvironStorageProviders("dummy", ec2.EBS_ProviderType)
	registry.RegisterEnvironStorageProviders("dummyenv", ec2.EBS_ProviderType)
}

func (s *assignCleanSuite) SetUpTest(c *gc.C) {
	c.Logf("assignment policy for this test: %q", s.policy)
	s.ConnSuite.SetUpTest(c)
	wordpress := s.AddTestingService(c, "wordpress", s.AddTestingCharm(c, "wordpress"))
	s.wordpress = wordpress
	pm := poolmanager.New(state.NewStateSettings(s.State), provider.CommonStorageProviders())
	_, err := pm.Create("loop-pool", provider.LoopProviderType, map[string]interface{}{})
	c.Assert(err, jc.ErrorIsNil)
}

func (s *baseSuite) setupStoragePool(c *gc.C) {
	pm := poolmanager.New(state.NewStateSettings(s.State))
	_, err := pm.Create("loop-pool", provider.LoopProviderType, map[string]interface{}{})
	c.Assert(err, jc.ErrorIsNil)
	err = s.State.UpdateEnvironConfig(map[string]interface{}{
		"storage-default-block-source": "loop-pool",
	}, nil, nil)
	c.Assert(err, jc.ErrorIsNil)
}

func newStorageProvisionerAPI(st *state.State, resources facade.Resources, authorizer facade.Authorizer) (*StorageProvisionerAPI, error) {
	env, err := stateenvirons.GetNewEnvironFunc(environs.New)(st)
	if err != nil {
		return nil, errors.Annotate(err, "getting environ")
	}
	registry := stateenvirons.NewStorageProviderRegistry(env)
	pm := poolmanager.New(state.NewStateSettings(st), registry)
	return NewStorageProvisionerAPI(stateShim{st}, resources, authorizer, registry, pm)
}

func (s *poolSuite) SetUpTest(c *gc.C) {
	s.StateSuite.SetUpTest(c)
	s.settings = state.NewStateSettings(s.State)
	s.registry = storage.StaticProviderRegistry{
		map[storage.ProviderType]storage.Provider{
			"loop": &dummystorage.StorageProvider{},
		},
	}
	s.poolManager = poolmanager.New(s.settings, s.registry)
}

func (s *MigrationImportSuite) TestStoragePools(c *gc.C) {
	pm := poolmanager.New(state.NewStateSettings(s.State), provider.CommonStorageProviders())
	_, err := pm.Create("test-pool", provider.LoopProviderType, map[string]interface{}{
		"value": 42,
	})
	c.Assert(err, jc.ErrorIsNil)

	_, newSt := s.importModel(c)

	pm = poolmanager.New(state.NewStateSettings(newSt), provider.CommonStorageProviders())
	pools, err := pm.List()
	c.Assert(err, jc.ErrorIsNil)
	c.Assert(pools, gc.HasLen, 1)

	pool := pools[0]
	c.Assert(pool.Name(), gc.Equals, "test-pool")
	c.Assert(pool.Provider(), gc.Equals, provider.LoopProviderType)
	c.Assert(pool.Attrs(), jc.DeepEquals, map[string]interface{}{
		"value": 42,
	})
}

// FilesystemParams returns the parameters for creating the filesystems
// with the specified tags.
func (s *StorageProvisionerAPI) FilesystemParams(args params.Entities) (params.FilesystemParamsResults, error) {
	canAccess, err := s.getStorageEntityAuthFunc()
	if err != nil {
		return params.FilesystemParamsResults{}, err
	}
	envConfig, err := s.st.EnvironConfig()
	if err != nil {
		return params.FilesystemParamsResults{}, err
	}
	results := params.FilesystemParamsResults{
		Results: make([]params.FilesystemParamsResult, len(args.Entities)),
	}
	poolManager := poolmanager.New(s.settings)
	one := func(arg params.Entity) (params.FilesystemParams, error) {
		tag, err := names.ParseFilesystemTag(arg.Tag)
		if err != nil || !canAccess(tag) {
			return params.FilesystemParams{}, common.ErrPerm
		}
		filesystem, err := s.st.Filesystem(tag)
		if errors.IsNotFound(err) {
			return params.FilesystemParams{}, common.ErrPerm
		} else if err != nil {
			return params.FilesystemParams{}, err
		}
		storageInstance, err := storagecommon.MaybeAssignedStorageInstance(
			filesystem.Storage,
			s.st.StorageInstance,
		)
		if err != nil {
			return params.FilesystemParams{}, err
		}
		filesystemParams, err := storagecommon.FilesystemParams(
			filesystem, storageInstance, envConfig, poolManager,
		)
		if err != nil {
			return params.FilesystemParams{}, err
		}
		return filesystemParams, nil
	}
	for i, arg := range args.Entities {
		var result params.FilesystemParamsResult
		filesystemParams, err := one(arg)
		if err != nil {
			result.Error = common.ServerError(err)
		} else {
			result.Result = filesystemParams
		}
		results.Results[i] = result
	}
	return results, nil
}

func (s *StorageStateSuiteBase) SetUpTest(c *gc.C) {
	s.ConnSuite.SetUpTest(c)

	// Create a default pool for block devices.
	pm := poolmanager.New(state.NewStateSettings(s.State), dummy.StorageProviders())
	_, err := pm.Create("loop-pool", provider.LoopProviderType, map[string]interface{}{})
	c.Assert(err, jc.ErrorIsNil)

	// Create a pool that creates persistent block devices.
	_, err = pm.Create("persistent-block", "environscoped-block", map[string]interface{}{
		"persistent": true,
	})
	c.Assert(err, jc.ErrorIsNil)
}

func (s *StorageStateSuite) TestNewModelDefaultPools(c *gc.C) {
	st := s.Factory.MakeModel(c, &factory.ModelParams{
		StorageProviderRegistry: testingStorageProviders,
	})
	s.AddCleanup(func(*gc.C) { st.Close() })

	// When a model is created, it is populated with the default
	// pools of each storage provider supported by the model's
	// cloud provider.
	pm := poolmanager.New(state.NewStateSettings(st), testingStorageProviders)
	listed, err := pm.List()
	c.Assert(err, jc.ErrorIsNil)
	sort.Sort(byStorageConfigName(listed))
	c.Assert(listed, jc.DeepEquals, []*storage.Config{blackPool, radiancePool})
}

func (i *importer) storagePools() error {
	registry, err := i.st.storageProviderRegistry()
	if err != nil {
		return errors.Annotate(err, "getting provider registry")
	}
	pm := poolmanager.New(NewStateSettings(i.st), registry)

	for _, pool := range i.model.StoragePools() {
		_, err := pm.Create(pool.Name(), storage.ProviderType(pool.Provider()), pool.Attributes())
		if err != nil {
			return errors.Annotatef(err, "creating pool %q", pool.Name())
		}
	}
	return nil
}

// storageConfig returns the provider type and config attributes for the
// specified poolName. If no such pool exists, we check to see if poolName is
// actually a provider type, in which case config will be empty.
func storageConfig(st *state.State, poolName string) (storage.ProviderType, map[string]interface{}, error) {
	pm := poolmanager.New(state.NewStateSettings(st))
	p, err := pm.Get(poolName)
	// If not a storage pool, then maybe a provider type.
	if errors.IsNotFound(err) {
		providerType := storage.ProviderType(poolName)
		if _, err1 := registry.StorageProvider(providerType); err1 != nil {
			return "", nil, errors.Trace(err)
		}
		return providerType, nil, nil
	}
	if err != nil {
		return "", nil, errors.Trace(err)
	}
	return p.Provider(), p.Attrs(), nil
}