func (c *DestroyEnvironmentCommand) Run(ctx *cmd.Context) (result error) {
	store, err := configstore.Default()
	if err != nil {
		return fmt.Errorf("cannot open environment info storage: %v", err)
	}
	environ, err := environs.NewFromName(c.envName, store)
	if err != nil {
		if environs.IsEmptyConfig(err) {
			// Delete the .jenv file and call it done.
			ctx.Infof("removing empty environment file")
			return environs.DestroyInfo(c.envName, store)
		}
		return err
	}
	if !c.assumeYes {
		fmt.Fprintf(ctx.Stdout, destroyEnvMsg, environ.Name(), environ.Config().Type())

		scanner := bufio.NewScanner(ctx.Stdin)
		scanner.Scan()
		err := scanner.Err()
		if err != nil && err != io.EOF {
			return fmt.Errorf("Environment destruction aborted: %s", err)
		}
		answer := strings.ToLower(scanner.Text())
		if answer != "y" && answer != "yes" {
			return errors.New("environment destruction aborted")
		}
	}
	// If --force is supplied, then don't attempt to use the API.
	// This is necessary to destroy broken environments, where the
	// API server is inaccessible or faulty.
	if !c.force {
		defer func() {
			if result == nil {
				return
			}
			logger.Errorf(`failed to destroy environment %q
        
If the environment is unusable, then you may run

    juju destroy-environment --force

to forcefully destroy the environment. Upon doing so, review
your environment provider console for any resources that need
to be cleaned up.

`, c.envName)
		}()
		apiclient, err := juju.NewAPIClientFromName(c.envName)
		if err != nil {
			return fmt.Errorf("cannot connect to API: %v", err)
		}
		defer apiclient.Close()
		err = apiclient.DestroyEnvironment()
		if err != nil && !params.IsCodeNotImplemented(err) {
			return fmt.Errorf("destroying environment: %v", err)
		}
	}
	return environs.Destroy(environ, store)
}

func (c *ResolvedCommand) Run(_ *cmd.Context) error {
	client, err := juju.NewAPIClientFromName(c.EnvName)
	if err != nil {
		return err
	}
	defer client.Close()
	return client.Resolved(c.UnitName, c.Retry)
}

// Run connects to the environment specified on the command line
// and calls EnsureAvailability.
func (c *EnsureAvailabilityCommand) Run(_ *cmd.Context) error {
	client, err := juju.NewAPIClientFromName(c.EnvName)
	if err != nil {
		return err
	}
	defer client.Close()
	return client.EnsureAvailability(c.NumStateServers, c.Constraints, c.Series)
}

// TODO(jam): 2013-08-27 This should move somewhere in api.*
func (*NewAPIClientSuite) TestMultipleCloseOk(c *gc.C) {
	defer coretesting.MakeSampleHome(c).Restore()
	bootstrapEnv(c, "", defaultConfigStore(c))
	client, _ := juju.NewAPIClientFromName("")
	c.Assert(client.Close(), gc.IsNil)
	c.Assert(client.Close(), gc.IsNil)
	c.Assert(client.Close(), gc.IsNil)
}

func (c *DestroyRelationCommand) Run(_ *cmd.Context) error {
	client, err := juju.NewAPIClientFromName(c.EnvName)
	if err != nil {
		return err
	}
	defer client.Close()
	return client.DestroyRelation(c.Endpoints...)
}

// Run changes the juju-managed firewall to hide any
// ports that were also explicitly marked by units as closed.
func (c *UnexposeCommand) Run(_ *cmd.Context) error {
	client, err := juju.NewAPIClientFromName(c.EnvName)
	if err != nil {
		return err
	}
	defer client.Close()
	return client.ServiceUnexpose(c.ServiceName)
}

// Run resets the configuration of a service.
func (c *UnsetCommand) Run(ctx *cmd.Context) error {
	apiclient, err := juju.NewAPIClientFromName(c.EnvName)
	if err != nil {
		return err
	}
	defer apiclient.Close()
	return apiclient.ServiceUnset(c.ServiceName, c.Options)
}

// Run connects to the environment specified on the command line and destroys
// units therein.
func (c *DestroyUnitCommand) Run(_ *cmd.Context) error {
	client, err := juju.NewAPIClientFromName(c.EnvName)
	if err != nil {
		return err
	}
	defer client.Close()
	return client.DestroyServiceUnits(c.UnitNames...)
}

func (c *UnsetEnvironmentCommand) Run(ctx *cmd.Context) error {
	client, err := juju.NewAPIClientFromName(c.EnvName)
	if err != nil {
		return err
	}
	defer client.Close()
	return client.EnvironmentUnset(c.keys...)
}

func (*NewAPIClientSuite) TestNameNotDefault(c *gc.C) {
	defer coretesting.MakeMultipleEnvHome(c).Restore()
	envName := coretesting.SampleCertName + "-2"
	bootstrapEnv(c, envName, defaultConfigStore(c))
	apiclient, err := juju.NewAPIClientFromName(envName)
	c.Assert(err, gc.IsNil)
	defer apiclient.Close()
	assertEnvironmentName(c, apiclient, envName)
}

// Run connects to the environment specified on the command line
// and calls AddServiceUnits for the given service.
func (c *AddUnitCommand) Run(_ *cmd.Context) error {
	apiclient, err := juju.NewAPIClientFromName(c.EnvName)
	if err != nil {
		return err
	}
	defer apiclient.Close()

	_, err = apiclient.AddServiceUnits(c.ServiceName, c.NumUnits, c.ToMachineSpec)
	return err
}

func (c *DestroyMachineCommand) Run(_ *cmd.Context) error {
	apiclient, err := juju.NewAPIClientFromName(c.EnvName)
	if err != nil {
		return err
	}
	defer apiclient.Close()
	if c.Force {
		return apiclient.ForceDestroyMachines(c.MachineIds...)
	}
	return apiclient.DestroyMachines(c.MachineIds...)
}

// ProvisionMachine provisions a machine agent to an existing host, via
// an SSH connection to the specified host. The host may optionally be preceded
// with a login username, as in [[email protected]]host.
//
// On successful completion, this function will return the id of the state.Machine
// that was entered into state.
func ProvisionMachine(args ProvisionMachineArgs) (machineId string, err error) {
	client, err := juju.NewAPIClientFromName(args.EnvName)
	if err != nil {
		return "", err
	}
	defer func() {
		if machineId != "" && err != nil {
			logger.Errorf("provisioning failed, removing machine %v: %v", machineId, err)
			if cleanupErr := client.DestroyMachines(machineId); cleanupErr != nil {
				logger.Warningf("error cleaning up machine: %s", cleanupErr)
			}
			machineId = ""
		}
		client.Close()
	}()

	// Create the "ubuntu" user and initialise passwordless sudo. We populate
	// the ubuntu user's authorized_keys file with the public keys in the current
	// user's ~/.ssh directory. The authenticationworker will later update the
	// ubuntu user's authorized_keys.
	user, hostname := splitUserHost(args.Host)
	authorizedKeys, err := config.ReadAuthorizedKeys("")
	if err := InitUbuntuUser(hostname, user, authorizedKeys, args.Stdin, args.Stdout); err != nil {
		return "", err
	}

	machineParams, err := gatherMachineParams(hostname)
	if err != nil {
		return "", err
	}

	// Inform Juju that the machine exists.
	machineId, err = recordMachineInState(client, *machineParams)
	if err != nil {
		return "", err
	}

	provisioningScript, err := client.ProvisioningScript(params.ProvisioningScriptParams{
		MachineId: machineId,
		Nonce:     machineParams.Nonce,
	})
	if err != nil {
		return "", err
	}

	// Finally, provision the machine agent.
	err = runProvisionScript(provisioningScript, hostname, args.Stderr)
	if err != nil {
		return machineId, err
	}

	logger.Infof("Provisioned machine %v", machineId)
	return machineId, nil
}

func (c *SetConstraintsCommand) Run(_ *cmd.Context) (err error) {
	apiclient, err := juju.NewAPIClientFromName(c.EnvName)
	if err != nil {
		return err
	}
	defer apiclient.Close()
	if c.ServiceName == "" {
		return apiclient.SetEnvironmentConstraints(c.Constraints)
	}
	return apiclient.SetServiceConstraints(c.ServiceName, c.Constraints)
}

func (c *RetryProvisioningCommand) Run(context *cmd.Context) error {
	client, err := juju.NewAPIClientFromName(c.EnvName)
	if err != nil {
		return err
	}
	defer client.Close()
	results, err := client.RetryProvisioning(c.Machines...)
	if err != nil {
		return err
	}
	for i, result := range results {
		if result.Error != nil {
			fmt.Fprintf(context.Stderr, "cannot retry provisioning %q: %v\n", c.Machines[i], result.Error)
		}
	}
	return nil
}

// Run changes the version proposed for the juju envtools.
func (c *UpgradeJujuCommand) Run(_ *cmd.Context) (err error) {
	client, err := juju.NewAPIClientFromName(c.EnvName)
	if err != nil {
		return err
	}
	defer client.Close()
	defer func() {
		if err == errUpToDate {
			logger.Infof(err.Error())
			err = nil
		}
	}()

	// Determine the version to upgrade to, uploading tools if necessary.
	attrs, err := client.EnvironmentGet()
	if err != nil {
		return err
	}
	cfg, err := config.New(config.NoDefaults, attrs)
	if err != nil {
		return err
	}
	context, err := c.initVersions(client, cfg)
	if err != nil {
		return err
	}
	if c.UploadTools {
		series := bootstrap.SeriesToUpload(cfg, c.Series)
		if err := context.uploadTools(series); err != nil {
			return err
		}
	}
	if err := context.validate(); err != nil {
		return err
	}
	logger.Infof("upgrade version chosen: %s", context.chosen)
	// TODO(fwereade): this list may be incomplete, pending envtools.Upload change.
	logger.Infof("available tools: %s", context.tools)

	if err := client.SetEnvironAgentVersion(context.chosen); err != nil {
		return err
	}
	logger.Infof("started upgrade to %s", context.chosen)
	return nil
}

// Run updates the configuration of a service.
func (c *SetCommand) Run(ctx *cmd.Context) error {
	api, err := juju.NewAPIClientFromName(c.EnvName)
	if err != nil {
		return err
	}
	defer api.Close()

	if c.SettingsYAML.Path != "" {
		b, err := c.SettingsYAML.Read(ctx)
		if err != nil {
			return err
		}
		return api.ServiceSetYAML(c.ServiceName, string(b))
	} else if len(c.SettingsStrings) == 0 {
		return nil
	}
	return api.ServiceSet(c.ServiceName, c.SettingsStrings)
}

func (s *NewAPIClientSuite) TestNameDefault(c *gc.C) {
	defer coretesting.MakeMultipleEnvHome(c).Restore()
	// The connection logic should not delay the config connection
	// at all when there is no environment info available.
	// Make sure of that by providing a suitably long delay
	// and checking that the connection happens within that
	// time.
	s.PatchValue(juju.ProviderConnectDelay, coretesting.LongWait)
	bootstrapEnv(c, coretesting.SampleEnvName, defaultConfigStore(c))

	startTime := time.Now()
	apiclient, err := juju.NewAPIClientFromName("")
	c.Assert(err, gc.IsNil)
	defer apiclient.Close()
	c.Assert(time.Since(startTime), jc.LessThan, coretesting.LongWait)

	// We should get the default sample environment if we ask for ""
	assertEnvironmentName(c, apiclient, coretesting.SampleEnvName)
}

// Run fetches the configuration of the service and formats
// the result as a YAML string.
func (c *GetCommand) Run(ctx *cmd.Context) error {
	client, err := juju.NewAPIClientFromName(c.EnvName)
	if err != nil {
		return err
	}
	defer client.Close()

	results, err := client.ServiceGet(c.ServiceName)
	if err != nil {
		return err
	}

	resultsMap := map[string]interface{}{
		"service":  results.Service,
		"charm":    results.Charm,
		"settings": results.Config,
	}
	return c.out.Write(ctx, resultsMap)
}

func (c *StatusCommand) Run(ctx *cmd.Context) error {
	// Just verify the pattern validity client side, do not use the matcher
	_, err := client.NewUnitMatcher(c.patterns)
	if err != nil {
		return err
	}
	apiclient, err := juju.NewAPIClientFromName(c.EnvName)
	if err != nil {
		return fmt.Errorf(connectionError, c.EnvName, err)
	}
	defer apiclient.Close()

	status, err := apiclient.Status(c.patterns)
	// Display any error, but continue to print status if some was returned
	if err != nil {
		fmt.Fprintf(ctx.Stderr, "%v\n", err)
	}
	result := formatStatus(status)
	return c.out.Write(ctx, result)
}