func (s *modelconfigSuite) assertBlocked(c *gc.C, err error, msg string) {
	c.Assert(params.IsCodeOperationBlocked(err), jc.IsTrue, gc.Commentf("error: %#v", err))
	c.Assert(errors.Cause(err), jc.DeepEquals, &params.Error{
		Message: msg,
		Code:    "operation is blocked",
	})
}

// ensureUserFriendlyErrorLog ensures that error will be logged and displayed
// in a user-friendly manner with readable and digestable error message.
func (c *destroyCommand) ensureUserFriendlyErrorLog(destroyErr error, ctx *cmd.Context, api destroyControllerAPI) error {
	if destroyErr == nil {
		return nil
	}
	if params.IsCodeOperationBlocked(destroyErr) {
		logger.Errorf(`there are blocks preventing controller destruction
To remove all blocks in the controller, please run:

    juju controller remove-blocks

`)
		if api != nil {
			envs, err := api.ListBlockedEnvironments()
			var bytes []byte
			if err == nil {
				bytes, err = formatTabularBlockedEnvironments(envs)
			}

			if err != nil {
				logger.Errorf("Unable to list blocked environments: %s", err)
				return cmd.ErrSilent
			}
			ctx.Infof(string(bytes))
		}
		return cmd.ErrSilent
	}
	logger.Errorf(stdFailureMsg, c.EnvName())
	return destroyErr
}

// ensureUserFriendlyErrorLog ensures that error will be logged and displayed
// in a user-friendly manner with readable and digestable error message.
func (c *destroyCommand) ensureUserFriendlyErrorLog(destroyErr error, ctx *cmd.Context, api destroyControllerAPI) error {
	if destroyErr == nil {
		return nil
	}
	if params.IsCodeOperationBlocked(destroyErr) {
		logger.Errorf(destroyControllerBlockedMsg)
		if api != nil {
			models, err := api.ListBlockedModels()
			out := &bytes.Buffer{}
			if err == nil {
				var info interface{}
				info, err = block.FormatModelBlockInfo(models)
				if err != nil {
					return errors.Trace(err)
				}
				err = block.FormatTabularBlockedModels(out, info)
			}
			if err != nil {
				logger.Errorf("Unable to list models: %s", err)
				return cmd.ErrSilent
			}
			ctx.Infof(out.String())
		}
		return cmd.ErrSilent
	}
	if params.IsCodeHasHostedModels(destroyErr) {
		return destroyErr
	}
	logger.Errorf(stdFailureMsg, c.ControllerName())
	return destroyErr
}

// ensureUserFriendlyErrorLog ensures that error will be logged and displayed
// in a user-friendly manner with readable and digestable error message.
func (c *destroyCommand) ensureUserFriendlyErrorLog(destroyErr error, ctx *cmd.Context, api destroyControllerAPI) error {
	if destroyErr == nil {
		return nil
	}
	if params.IsCodeOperationBlocked(destroyErr) {
		logger.Errorf(destroyControllerBlockedMsg)
		if api != nil {
			models, err := api.ListBlockedModels()
			var bytes []byte
			if err == nil {
				bytes, err = formatTabularBlockedModels(models)
			}
			if err != nil {
				logger.Errorf("Unable to list blocked models: %s", err)
				return cmd.ErrSilent
			}
			ctx.Infof(string(bytes))
		}
		return cmd.ErrSilent
	}
	if params.IsCodeHasHostedModels(destroyErr) {
		return destroyErr
	}
	logger.Errorf(stdFailureMsg, c.ControllerName())
	return destroyErr
}

func (s *clientSuite) AssertBlocked(c *gc.C, err error, msg string) {
	c.Assert(params.IsCodeOperationBlocked(err), jc.IsTrue, gc.Commentf("error: %#v", err))
	c.Assert(errors.Cause(err), gc.DeepEquals, &rpc.RequestError{
		Message: msg,
		Code:    "operation is blocked",
	})
}

func (s *blockCheckerSuite) assertErrorBlocked(c *gc.C, blocked bool, err error, msg string) {
	if blocked {
		c.Assert(params.IsCodeOperationBlocked(err), jc.IsTrue)
		c.Assert(err, gc.ErrorMatches, msg)
	} else {
		c.Assert(errors.Cause(err), jc.ErrorIsNil)
	}
}

// processDestroyError determines how to format error message based on its code.
// Note that CodeNotImplemented errors have not be propogated in previous implementation.
// This behaviour was preserved.
func processDestroyError(err error) error {
	if err == nil || params.IsCodeNotImplemented(err) {
		return nil
	}
	if params.IsCodeOperationBlocked(err) {
		return err
	}
	return errors.Annotate(err, "destroying environment")
}

func (c *destroyCommand) handleError(err error) error {
	if err == nil {
		return nil
	}
	if params.IsCodeOperationBlocked(err) {
		return block.ProcessBlockedError(err, block.BlockDestroy)
	}
	logger.Errorf(`failed to destroy environment %q`, c.envName)
	return err
}

func (c *destroyCommand) handleError(err error, modelName string) error {
	if err == nil {
		return nil
	}
	if params.IsCodeOperationBlocked(err) {
		return block.ProcessBlockedError(err, block.BlockDestroy)
	}
	logger.Errorf(`failed to destroy model %q`, modelName)
	return err
}

// ProcessBlockedError ensures that correct and user-friendly message is
// displayed to the user based on the block type.
func ProcessBlockedError(err error, block Block) error {
	if err == nil {
		return nil
	}
	if params.IsCodeOperationBlocked(err) {
		logger.Errorf("\n%v%v", err, blockedMessages[block])
		return cmd.ErrSilent
	}
	return err
}

// ensureUserFriendlyErrorLog ensures that error will be logged and displayed
// in a user-friendly manner with readable and digestable error message.
func (c *destroyEnvironmentCommand) ensureUserFriendlyErrorLog(err error) error {
	if err == nil {
		return nil
	}
	if params.IsCodeOperationBlocked(err) {
		return block.ProcessBlockedError(err, block.BlockDestroy)
	}
	logger.Errorf(stdFailureMsg, c.EnvName())
	return err
}

// ProcessBlockedError ensures that correct and user-friendly message is
// displayed to the user based on the block type.
func ProcessBlockedError(err error, block Block) error {
	if err == nil {
		return nil
	}
	if params.IsCodeOperationBlocked(err) {
		msg := blockedMessages[block]
		logger.Errorf("%v\n%v", err, msg)
		return errors.New(msg)
	}
	return err
}

func (s *destroyControllerSuite) TestDestroyControllerNoHostedEnvsWithBlockFail(c *gc.C) {
	err := common.DestroyModel(s.State, s.otherState.ModelTag())
	c.Assert(err, jc.ErrorIsNil)

	s.BlockDestroyModel(c, "TestBlockDestroyModel")
	s.BlockRemoveObject(c, "TestBlockRemoveObject")

	err = s.controller.DestroyController(params.DestroyControllerArgs{})
	c.Assert(params.IsCodeOperationBlocked(err), jc.IsTrue)

	numBlocks, err := s.State.AllBlocksForController()
	c.Assert(err, jc.ErrorIsNil)
	c.Assert(len(numBlocks), gc.Equals, 2)
}

func (s *destroySystemSuite) TestDestroySystemNoHostedEnvsWithBlockFail(c *gc.C) {
	err := common.DestroyEnvironment(s.State, s.otherState.EnvironTag())
	c.Assert(err, jc.ErrorIsNil)

	s.BlockDestroyEnvironment(c, "TestBlockDestroyEnvironment")
	s.BlockRemoveObject(c, "TestBlockRemoveObject")

	err = s.systemManager.DestroySystem(params.DestroySystemArgs{})
	c.Assert(params.IsCodeOperationBlocked(err), jc.IsTrue)

	numBlocks, err := s.State.AllBlocksForSystem()
	c.Assert(err, jc.ErrorIsNil)
	c.Assert(len(numBlocks), gc.Equals, 2)
}

func (s *destroySystemSuite) TestDestroySystemReturnsBlockedEnvironmentsErr(c *gc.C) {
	s.BlockDestroyEnvironment(c, "TestBlockDestroyEnvironment")
	s.BlockRemoveObject(c, "TestBlockRemoveObject")
	s.otherState.SwitchBlockOn(state.DestroyBlock, "TestBlockDestroyEnvironment")
	s.otherState.SwitchBlockOn(state.ChangeBlock, "TestChangeBlock")

	err := s.systemManager.DestroySystem(params.DestroySystemArgs{
		DestroyEnvironments: true,
	})
	c.Assert(params.IsCodeOperationBlocked(err), jc.IsTrue)

	numBlocks, err := s.State.AllBlocksForSystem()
	c.Assert(err, jc.ErrorIsNil)
	c.Assert(len(numBlocks), gc.Equals, 4)

	_, err = s.otherState.Environment()
	c.Assert(err, jc.ErrorIsNil)
}

func (s *destroyControllerSuite) TestDestroyControllerReturnsBlockedEnvironmentsErr(c *gc.C) {
	s.BlockDestroyModel(c, "TestBlockDestroyModel")
	s.BlockRemoveObject(c, "TestBlockRemoveObject")
	s.otherState.SwitchBlockOn(state.DestroyBlock, "TestBlockDestroyModel")
	s.otherState.SwitchBlockOn(state.ChangeBlock, "TestChangeBlock")

	err := s.controller.DestroyController(params.DestroyControllerArgs{
		DestroyModels: true,
	})
	c.Assert(params.IsCodeOperationBlocked(err), jc.IsTrue)

	numBlocks, err := s.State.AllBlocksForController()
	c.Assert(err, jc.ErrorIsNil)
	c.Assert(len(numBlocks), gc.Equals, 4)

	_, err = s.otherState.Model()
	c.Assert(err, jc.ErrorIsNil)
}

//.........这里部分代码省略.........
	config, err := config.New(config.NoDefaults, configAttrs)
	if err != nil {
		return errors.Trace(err)
	}

	if c.Placement != nil && c.Placement.Scope == "ssh" {
		logger.Infof("manual provisioning")
		authKeys, err := common.ReadAuthorizedKeys(ctx, "")
		if err != nil {
			return errors.Annotate(err, "reading authorized-keys")
		}
		args := manual.ProvisionMachineArgs{
			Host:           c.Placement.Directive,
			Client:         client,
			Stdin:          ctx.Stdin,
			Stdout:         ctx.Stdout,
			Stderr:         ctx.Stderr,
			AuthorizedKeys: authKeys,
			UpdateBehavior: &params.UpdateBehavior{
				config.EnableOSRefreshUpdate(),
				config.EnableOSUpgrade(),
			},
		}
		machineId, err := manualProvisioner(args)
		if err == nil {
			ctx.Infof("created machine %v", machineId)
		}
		return err
	}

	logger.Infof("model provisioning")
	if c.Placement != nil && c.Placement.Scope == "model-uuid" {
		uuid, ok := client.ModelUUID()
		if !ok {
			return errors.New("API connection is controller-only (should never happen)")
		}
		c.Placement.Scope = uuid
	}

	if c.Placement != nil && c.Placement.Scope == instance.MachineScope {
		// It does not make sense to add-machine <id>.
		return errors.Errorf("machine-id cannot be specified when adding machines")
	}

	jobs := []multiwatcher.MachineJob{multiwatcher.JobHostUnits}

	machineParams := params.AddMachineParams{
		Placement:   c.Placement,
		Series:      c.Series,
		Constraints: c.Constraints,
		Jobs:        jobs,
		Disks:       c.Disks,
	}
	machines := make([]params.AddMachineParams, c.NumMachines)
	for i := 0; i < c.NumMachines; i++ {
		machines[i] = machineParams
	}

	var results []params.AddMachinesResult
	// If storage is specified, we attempt to use a new API on the service facade.
	if len(c.Disks) > 0 {
		results, err = machineManager.AddMachines(machines)
	} else {
		results, err = client.AddMachines(machines)
	}
	if params.IsCodeOperationBlocked(err) {
		return block.ProcessBlockedError(err, block.BlockChange)
	}
	if err != nil {
		return errors.Trace(err)
	}

	errs := []error{}
	for _, machineInfo := range results {
		if machineInfo.Error != nil {
			errs = append(errs, machineInfo.Error)
			continue
		}
		machineId := machineInfo.Machine

		if names.IsContainerMachine(machineId) {
			ctx.Infof("created container %v", machineId)
		} else {
			ctx.Infof("created machine %v", machineId)
		}
	}
	if len(errs) == 1 {
		fmt.Fprint(ctx.Stderr, "failed to create 1 machine\n")
		return errs[0]
	}
	if len(errs) > 1 {
		fmt.Fprintf(ctx.Stderr, "failed to create %d machines\n", len(errs))
		returnErr := []string{}
		for _, e := range errs {
			returnErr = append(returnErr, e.Error())
		}
		return errors.New(strings.Join(returnErr, ", "))
	}
	return nil
}

// AssertBlocked checks if given error is
// related to switched block.
func (s BlockHelper) AssertBlocked(c *gc.C, err error, msg string) {
	c.Assert(params.IsCodeOperationBlocked(err), jc.IsTrue, gc.Commentf("error: %#v", err))
	c.Assert(err, gc.ErrorMatches, msg)
}

func (c *addCommand) Run(ctx *cmd.Context) error {
	client, err := c.getClientAPI()
	if err != nil {
		return errors.Trace(err)
	}
	defer client.Close()

	var machineManager MachineManagerAPI
	if len(c.Disks) > 0 {
		machineManager, err = c.getMachineManagerAPI()
		if err != nil {
			return errors.Trace(err)
		}
		defer machineManager.Close()
		if machineManager.BestAPIVersion() < 1 {
			return errors.New("cannot add machines with disks: not supported by the API server")
		}
	}

	logger.Infof("load config")
	configAttrs, err := client.ModelGet()
	if err != nil {
		return errors.Trace(err)
	}
	config, err := config.New(config.NoDefaults, configAttrs)
	if err != nil {
		return errors.Trace(err)
	}

	if c.Placement != nil && c.Placement.Scope == "ssh" {
		logger.Infof("manual provisioning")
		args := manual.ProvisionMachineArgs{
			Host:   c.Placement.Directive,
			Client: client,
			Stdin:  ctx.Stdin,
			Stdout: ctx.Stdout,
			Stderr: ctx.Stderr,
			UpdateBehavior: &params.UpdateBehavior{
				config.EnableOSRefreshUpdate(),
				config.EnableOSUpgrade(),
			},
		}
		machineId, err := manualProvisioner(args)
		if err == nil {
			ctx.Infof("created machine %v", machineId)
		}
		return err
	}

	logger.Infof("model provisioning")
	if c.Placement != nil && c.Placement.Scope == "model-uuid" {
		c.Placement.Scope = client.ModelUUID()
	}

	if c.Placement != nil && c.Placement.Scope == instance.MachineScope {
		// It does not make sense to add-machine <id>.
		return fmt.Errorf("machine-id cannot be specified when adding machines")
	}

	jobs := []multiwatcher.MachineJob{multiwatcher.JobHostUnits}

	// In case of MAAS and Joyent JobManageNetworking is not added
	// to ensure the non-intrusive start of a networker like above
	// for the manual provisioning. See this related joyent bug
	// http://pad.lv/1401423
	if config.Type() != provider.MAAS && config.Type() != provider.Joyent {
		jobs = append(jobs, multiwatcher.JobManageNetworking)
	}

	machineParams := params.AddMachineParams{
		Placement:   c.Placement,
		Series:      c.Series,
		Constraints: c.Constraints,
		Jobs:        jobs,
		Disks:       c.Disks,
	}
	machines := make([]params.AddMachineParams, c.NumMachines)
	for i := 0; i < c.NumMachines; i++ {
		machines[i] = machineParams
	}

	var results []params.AddMachinesResult
	// If storage is specified, we attempt to use a new API on the service facade.
	if len(c.Disks) > 0 {
		results, err = machineManager.AddMachines(machines)
	} else {
		results, err = client.AddMachines(machines)
	}
	if params.IsCodeOperationBlocked(err) {
		return block.ProcessBlockedError(err, block.BlockChange)
	}
	if err != nil {
		return errors.Trace(err)
	}

	errs := []error{}
	for _, machineInfo := range results {
		if machineInfo.Error != nil {
			errs = append(errs, machineInfo.Error)
			continue
//.........这里部分代码省略.........

func (s *baseStorageSuite) assertBlocked(c *gc.C, err error, msg string) {
	c.Assert(params.IsCodeOperationBlocked(err), jc.IsTrue)
	c.Assert(err, gc.ErrorMatches, msg)
}