func (s *JujuConnSuite) setUpConn(c *gc.C) {
	if s.RootDir != "" {
		panic("JujuConnSuite.setUpConn without teardown")
	}
	s.RootDir = c.MkDir()
	s.oldHome = utils.Home()
	home := filepath.Join(s.RootDir, "/home/ubuntu")
	err := os.MkdirAll(home, 0777)
	c.Assert(err, gc.IsNil)
	utils.SetHome(home)
	s.oldJujuHome = osenv.SetJujuHome(filepath.Join(home, ".juju"))
	err = os.Mkdir(osenv.JujuHome(), 0777)
	c.Assert(err, gc.IsNil)

	err = os.MkdirAll(s.DataDir(), 0777)
	c.Assert(err, gc.IsNil)
	s.PatchEnvironment(osenv.JujuEnvEnvKey, "")

	// TODO(rog) remove these files and add them only when
	// the tests specifically need them (in cmd/juju for example)
	s.writeSampleConfig(c, osenv.JujuHomePath("environments.yaml"))

	err = ioutil.WriteFile(osenv.JujuHomePath("dummyenv-cert.pem"), []byte(testing.CACert), 0666)
	c.Assert(err, gc.IsNil)

	err = ioutil.WriteFile(osenv.JujuHomePath("dummyenv-private-key.pem"), []byte(testing.CAKey), 0600)
	c.Assert(err, gc.IsNil)

	store, err := configstore.Default()
	c.Assert(err, gc.IsNil)
	s.ConfigStore = store

	ctx := testing.Context(c)
	environ, err := environs.PrepareFromName("dummyenv", ctx, s.ConfigStore)
	c.Assert(err, gc.IsNil)
	// sanity check we've got the correct environment.
	c.Assert(environ.Config().Name(), gc.Equals, "dummyenv")
	s.PatchValue(&dummy.DataDir, s.DataDir())
	s.LogDir = c.MkDir()
	s.PatchValue(&dummy.LogDir, s.LogDir)

	versions := PreferredDefaultVersions(environ.Config(), version.Binary{Number: version.Current.Number, Series: "precise", Arch: "amd64"})
	versions = append(versions, version.Current)

	// Upload tools for both preferred and fake default series
	envtesting.MustUploadFakeToolsVersions(environ.Storage(), versions...)
	err = bootstrap.Bootstrap(ctx, environ, bootstrap.BootstrapParams{})
	c.Assert(err, gc.IsNil)

	s.BackingState = environ.(GetStater).GetStateInAPIServer()

	s.State, err = newState(environ, s.BackingState.MongoConnectionInfo())
	c.Assert(err, gc.IsNil)

	s.APIState, err = juju.NewAPIState(environ, api.DialOpts{})
	c.Assert(err, gc.IsNil)

	s.Environ = environ
}

// WriteEnvironments creates an environments file with envConfig and certs
// from certNames.
func WriteEnvironments(c *gc.C, envConfig string, certNames ...string) {
	envs := osenv.JujuHomePath("environments.yaml")
	err := ioutil.WriteFile(envs, []byte(envConfig), 0644)
	c.Assert(err, gc.IsNil)
	for _, name := range certNames {
		err := ioutil.WriteFile(osenv.JujuHomePath(name+"-cert.pem"), []byte(CACert), 0600)
		c.Assert(err, gc.IsNil)
		err = ioutil.WriteFile(osenv.JujuHomePath(name+"-private-key.pem"), []byte(CAKey), 0600)
		c.Assert(err, gc.IsNil)
	}
}

// InitJujuHome initializes the charm cache, environs/config and utils/ssh packages
// to use default paths based on the $JUJU_HOME or $HOME environment variables.
// This function should be called before running a Juju CLI command.
func InitJujuHome() error {
	jujuHome := osenv.JujuHomeDir()
	if jujuHome == "" {
		return errors.New("cannot determine juju home, required model variables are not set")
	}
	osenv.SetJujuHome(jujuHome)
	charmrepo.CacheDir = osenv.JujuHomePath("charmcache")
	if err := ssh.LoadClientKeys(osenv.JujuHomePath("ssh")); err != nil {
		return errors.Annotate(err, "cannot load ssh client keys")
	}
	return nil
}

// InitJujuHome initializes the charm cache, environs/config and utils/ssh packages
// to use default paths based on the $JUJU_HOME or $HOME environment variables.
// This function should be called before running a Juju CLI command.
func InitJujuHome() error {
	jujuHome := osenv.JujuHomeDir()
	if jujuHome == "" {
		return stderrors.New(
			"cannot determine juju home, required environment variables are not set")
	}
	osenv.SetJujuHome(jujuHome)
	charmrepo.CacheDir = osenv.JujuHomePath("charmcache")
	if err := ssh.LoadClientKeys(osenv.JujuHomePath("ssh")); err != nil {
		return fmt.Errorf("cannot load ssh client keys: %v", err)
	}
	return nil
}

// maybeReadAttrFromFile sets defined[attr] to:
//
// 1) The content of the file defined[attr+"-path"], if that's set
// 2) The value of defined[attr] if it is already set.
// 3) The content of defaultPath if it exists and defined[attr] is unset
// 4) Preserves the content of defined[attr], otherwise
//
// The defined[attr+"-path"] key is always deleted.
func maybeReadAttrFromFile(defined map[string]interface{}, attr, defaultPath string) error {
	pathAttr := attr + "-path"
	path, _ := defined[pathAttr].(string)
	delete(defined, pathAttr)
	hasPath := path != ""
	if !hasPath {
		// No path and attribute is already set; leave it be.
		if s, _ := defined[attr].(string); s != "" {
			return nil
		}
		path = defaultPath
	}
	path, err := utils.NormalizePath(path)
	if err != nil {
		return err
	}
	if !filepath.IsAbs(path) {
		path = osenv.JujuHomePath(path)
	}
	data, err := ioutil.ReadFile(path)
	if err != nil {
		if os.IsNotExist(err) && !hasPath {
			// If the default path isn't found, it's
			// not an error.
			return nil
		}
		return err
	}
	if len(data) == 0 {
		return fmt.Errorf("file %q is empty", path)
	}
	defined[attr] = string(data)
	return nil
}

func NewJujuCommand(ctx *cmd.Context) cmd.Command {
	jcmd := jujucmd.NewSuperCommand(cmd.SuperCommandParams{
		Name:                "juju",
		Doc:                 jujuDoc,
		MissingCallback:     RunPlugin,
		UserAliasesFilename: osenv.JujuHomePath("aliases"),
	})
	jcmd.AddHelpTopic("basics", "Basic commands", helptopics.Basics)
	jcmd.AddHelpTopic("local-provider", "How to configure a local (LXC) provider",
		helptopics.LocalProvider)
	jcmd.AddHelpTopic("openstack-provider", "How to configure an OpenStack provider",
		helptopics.OpenstackProvider, "openstack")
	jcmd.AddHelpTopic("ec2-provider", "How to configure an Amazon EC2 provider",
		helptopics.EC2Provider, "ec2", "aws", "amazon")
	jcmd.AddHelpTopic("hpcloud-provider", "How to configure an HP Cloud provider",
		helptopics.HPCloud, "hpcloud", "hp-cloud")
	jcmd.AddHelpTopic("azure-provider", "How to configure a Windows Azure provider",
		helptopics.AzureProvider, "azure")
	jcmd.AddHelpTopic("maas-provider", "How to configure a MAAS provider",
		helptopics.MAASProvider, "maas")
	jcmd.AddHelpTopic("constraints", "How to use commands with constraints", helptopics.Constraints)
	jcmd.AddHelpTopic("placement", "How to use placement directives", helptopics.Placement)
	jcmd.AddHelpTopic("spaces", "How to configure more complex networks using spaces", helptopics.Spaces, "networking")
	jcmd.AddHelpTopic("glossary", "Glossary of terms", helptopics.Glossary)
	jcmd.AddHelpTopic("logging", "How Juju handles logging", helptopics.Logging)
	jcmd.AddHelpTopic("juju", "What is Juju?", helptopics.Juju)
	jcmd.AddHelpTopic("controllers", "About Juju Controllers", helptopics.JujuControllers)
	jcmd.AddHelpTopic("users", "About users in Juju", helptopics.Users)
	jcmd.AddHelpTopicCallback("plugins", "Show Juju plugins", PluginHelpTopic)

	registerCommands(jcmd, ctx)
	return jcmd
}

func (s *JujuHomeSuite) TestErrorHome(c *gc.C) {
	// Invalid juju home leads to panic when retrieving.
	f := func() { _ = osenv.JujuHome() }
	c.Assert(f, gc.PanicMatches, "juju home hasn't been initialized")
	f = func() { _ = osenv.JujuHomePath("environments.yaml") }
	c.Assert(f, gc.PanicMatches, "juju home hasn't been initialized")
}

func setCacheDir() {
	jujuHome := osenv.JujuHomeDir()
	if jujuHome == "" {
		log.Fatal("cannot determine juju home, required environment variables are not set")
	}
	osenv.SetJujuHome(jujuHome)
	charmrepo.CacheDir = osenv.JujuHomePath("charmcache")
}

// WriteConfig writes a juju config file to the "home" directory.
func (s *JujuConnSuite) WriteConfig(configData string) {
	if s.RootDir == "" {
		panic("SetUpTest has not been called; will not overwrite $JUJU_HOME/environments.yaml")
	}
	path := osenv.JujuHomePath("environments.yaml")
	err := ioutil.WriteFile(path, []byte(configData), 0600)
	if err != nil {
		panic(err)
	}
}

// Validate implements environs.EnvironProvider.Validate.
func (provider environProvider) Validate(cfg, old *config.Config) (valid *config.Config, err error) {
	// Check for valid changes for the base config values.
	if err := config.Validate(cfg, old); err != nil {
		return nil, err
	}
	validated, err := cfg.ValidateUnknownAttrs(configFields, configDefaults)
	if err != nil {
		return nil, fmt.Errorf("failed to validate unknown attrs: %v", err)
	}
	localConfig := newEnvironConfig(cfg, validated)
	// Before potentially creating directories, make sure that the
	// root directory has not changed.
	containerType := localConfig.container()
	if old != nil {
		oldLocalConfig, err := provider.newConfig(old)
		if err != nil {
			return nil, fmt.Errorf("old config is not a valid local config: %v", old)
		}
		if containerType != oldLocalConfig.container() {
			return nil, fmt.Errorf("cannot change container from %q to %q",
				oldLocalConfig.container(), containerType)
		}
		if localConfig.rootDir() != oldLocalConfig.rootDir() {
			return nil, fmt.Errorf("cannot change root-dir from %q to %q",
				oldLocalConfig.rootDir(),
				localConfig.rootDir())
		}
		if localConfig.networkBridge() != oldLocalConfig.networkBridge() {
			return nil, fmt.Errorf("cannot change network-bridge from %q to %q",
				oldLocalConfig.rootDir(),
				localConfig.rootDir())
		}
		if localConfig.storagePort() != oldLocalConfig.storagePort() {
			return nil, fmt.Errorf("cannot change storage-port from %v to %v",
				oldLocalConfig.storagePort(),
				localConfig.storagePort())
		}
	}
	// Currently only supported containers are "lxc" and "kvm".
	if containerType != instance.LXC && containerType != instance.KVM {
		return nil, fmt.Errorf("unsupported container type: %q", containerType)
	}
	dir, err := utils.NormalizePath(localConfig.rootDir())
	if err != nil {
		return nil, err
	}
	if dir == "." {
		dir = osenv.JujuHomePath(cfg.Name())
	}
	// Always assign the normalized path.
	localConfig.attrs["root-dir"] = dir

	// Apply the coerced unknown values back into the config.
	return cfg.Apply(localConfig.attrs)
}

func (s *NewAPIClientSuite) TestWithBootstrapConfigAndNoEnvironmentsFile(c *gc.C) {
	coretesting.MakeSampleJujuHome(c)
	store := configstore.NewMem()
	s.bootstrapEnv(c, coretesting.SampleEnvName, store)
	info, err := store.ReadInfo(coretesting.SampleEnvName)
	c.Assert(err, jc.ErrorIsNil)
	c.Assert(info.BootstrapConfig(), gc.NotNil)
	c.Assert(info.APIEndpoint().Addresses, gc.HasLen, 0)

	err = os.Remove(osenv.JujuHomePath("environments.yaml"))
	c.Assert(err, jc.ErrorIsNil)

	apiOpen := func(*api.Info, api.DialOpts) (juju.APIState, error) {
		return mockedAPIState(noFlags), nil
	}
	st, err := juju.NewAPIFromStore(coretesting.SampleEnvName, store, apiOpen)
	c.Check(err, jc.ErrorIsNil)
	st.Close()
}

// Validate implements environs.EnvironProvider.Validate.
func (provider environProvider) Validate(cfg, old *config.Config) (valid *config.Config, err error) {
	// Check for valid changes for the base config values.
	if err := config.Validate(cfg, old); err != nil {
		return nil, err
	}
	validated, err := cfg.ValidateUnknownAttrs(configFields, configDefaults)
	if err != nil {
		return nil, errors.Annotatef(err, "failed to validate unknown attrs")
	}
	localConfig := newEnvironConfig(cfg, validated)
	// Set correct default network bridge if needed
	// fix for http://pad.lv/1394450
	localConfig.setDefaultNetworkBridge()
	// Before potentially creating directories, make sure that the
	// root directory has not changed.
	if localConfig.namespace() == "" {
		return nil, errors.New("missing namespace, config not prepared")
	}
	containerType := localConfig.container()
	if old != nil {
		oldLocalConfig, err := provider.newConfig(old)
		if err != nil {
			return nil, errors.Annotatef(err, "old config is not a valid local config: %v", old)
		}
		if containerType != oldLocalConfig.container() {
			return nil, errors.Errorf("cannot change container from %q to %q",
				oldLocalConfig.container(), containerType)
		}
		if localConfig.rootDir() != oldLocalConfig.rootDir() {
			return nil, errors.Errorf("cannot change root-dir from %q to %q",
				oldLocalConfig.rootDir(),
				localConfig.rootDir())
		}
		if localConfig.networkBridge() != oldLocalConfig.networkBridge() {
			return nil, errors.Errorf("cannot change network-bridge from %q to %q",
				oldLocalConfig.rootDir(),
				localConfig.rootDir())
		}
		if localConfig.storagePort() != oldLocalConfig.storagePort() {
			return nil, errors.Errorf("cannot change storage-port from %v to %v",
				oldLocalConfig.storagePort(),
				localConfig.storagePort())
		}
		if localConfig.namespace() != oldLocalConfig.namespace() {
			return nil, errors.Errorf("cannot change namespace from %v to %v",
				oldLocalConfig.namespace(),
				localConfig.namespace())
		}
	}
	// Currently only supported containers are "lxc" and "kvm".
	if containerType != instance.LXC && containerType != instance.KVM {
		return nil, errors.Errorf("unsupported container type: %q", containerType)
	}
	dir, err := utils.NormalizePath(localConfig.rootDir())
	if err != nil {
		return nil, err
	}
	if dir == "." {
		dir = osenv.JujuHomePath(cfg.Name())
	}
	// Always assign the normalized path.
	localConfig.attrs["root-dir"] = dir

	// If the user hasn't already specified a value, set it to the
	// given value.
	defineIfNot := func(keyName string, value interface{}) {
		if _, defined := cfg.AllAttrs()[keyName]; !defined {
			logger.Infof("lxc-clone is enabled. Switching %s to %v", keyName, value)
			localConfig.attrs[keyName] = value
		}
	}

	// If we're cloning, and the user hasn't specified otherwise,
	// prefer to skip update logic.
	if useClone, _ := localConfig.LXCUseClone(); useClone && containerType == instance.LXC {
		defineIfNot("enable-os-refresh-update", true)
		defineIfNot("enable-os-upgrade", false)
	}

	// Apply the coerced unknown values back into the config.
	return cfg.Apply(localConfig.attrs)
}

func (s *JujuConnSuite) setUpConn(c *gc.C) {
	if s.RootDir != "" {
		panic("JujuConnSuite.setUpConn without teardown")
	}
	s.RootDir = c.MkDir()
	s.oldHome = utils.Home()
	home := filepath.Join(s.RootDir, "/home/ubuntu")
	err := os.MkdirAll(home, 0777)
	c.Assert(err, jc.ErrorIsNil)
	utils.SetHome(home)
	s.oldJujuHome = osenv.SetJujuHome(filepath.Join(home, ".juju"))
	err = os.Mkdir(osenv.JujuHome(), 0777)
	c.Assert(err, jc.ErrorIsNil)

	err = os.MkdirAll(s.DataDir(), 0777)
	c.Assert(err, jc.ErrorIsNil)
	s.PatchEnvironment(osenv.JujuEnvEnvKey, "")

	// TODO(rog) remove these files and add them only when
	// the tests specifically need them (in cmd/juju for example)
	s.writeSampleConfig(c, osenv.JujuHomePath("environments.yaml"))

	err = ioutil.WriteFile(osenv.JujuHomePath("dummyenv-cert.pem"), []byte(testing.CACert), 0666)
	c.Assert(err, jc.ErrorIsNil)

	err = ioutil.WriteFile(osenv.JujuHomePath("dummyenv-private-key.pem"), []byte(testing.CAKey), 0600)
	c.Assert(err, jc.ErrorIsNil)

	store, err := configstore.Default()
	c.Assert(err, jc.ErrorIsNil)
	s.ConfigStore = store

	ctx := testing.Context(c)
	environ, err := environs.PrepareFromName("dummyenv", envcmd.BootstrapContext(ctx), s.ConfigStore)
	c.Assert(err, jc.ErrorIsNil)
	// sanity check we've got the correct environment.
	c.Assert(environ.Config().Name(), gc.Equals, "dummyenv")
	s.PatchValue(&dummy.DataDir, s.DataDir())
	s.LogDir = c.MkDir()
	s.PatchValue(&dummy.LogDir, s.LogDir)

	versions := PreferredDefaultVersions(environ.Config(), version.Binary{Number: version.Current.Number, Series: "precise", Arch: "amd64"})
	versions = append(versions, version.Current)

	// Upload tools for both preferred and fake default series
	s.DefaultToolsStorageDir = c.MkDir()
	s.PatchValue(&tools.DefaultBaseURL, s.DefaultToolsStorageDir)
	stor, err := filestorage.NewFileStorageWriter(s.DefaultToolsStorageDir)
	c.Assert(err, jc.ErrorIsNil)
	// Upload tools to both release and devel streams since config will dictate that we
	// end up looking in both places.
	envtesting.AssertUploadFakeToolsVersions(c, stor, "released", "released", versions...)
	envtesting.AssertUploadFakeToolsVersions(c, stor, "devel", "devel", versions...)
	s.DefaultToolsStorage = stor

	err = bootstrap.Bootstrap(envcmd.BootstrapContext(ctx), environ, bootstrap.BootstrapParams{})
	c.Assert(err, jc.ErrorIsNil)

	s.BackingState = environ.(GetStater).GetStateInAPIServer()

	s.State, err = newState(environ, s.BackingState.MongoConnectionInfo())
	c.Assert(err, jc.ErrorIsNil)

	s.APIState, err = juju.NewAPIState(s.AdminUserTag(c), environ, api.DialOpts{})
	c.Assert(err, jc.ErrorIsNil)

	err = s.State.SetAPIHostPorts(s.APIState.APIHostPorts())
	c.Assert(err, jc.ErrorIsNil)

	// Make sure the config store has the api endpoint address set
	info, err := s.ConfigStore.ReadInfo("dummyenv")
	c.Assert(err, jc.ErrorIsNil)
	endpoint := info.APIEndpoint()
	endpoint.Addresses = []string{s.APIState.APIHostPorts()[0][0].String()}
	info.SetAPIEndpoint(endpoint)
	err = info.Write()
	c.Assert(err, jc.ErrorIsNil)

	// Make sure the jenv file has the local host ports.
	c.Logf("jenv host ports: %#v", s.APIState.APIHostPorts())

	s.Environ = environ

	// Insert expected values...
	servingInfo := state.StateServingInfo{
		PrivateKey:   testing.ServerKey,
		Cert:         testing.ServerCert,
		CAPrivateKey: testing.CAKey,
		SharedSecret: "really, really secret",
		APIPort:      4321,
		StatePort:    1234,
	}
	s.State.SetStateServingInfo(servingInfo)
}

func environsPath(path string) string {
	if path == "" {
		path = osenv.JujuHomePath("environments.yaml")
	}
	return path
}

func (s *JujuHomeSuite) TestHomePath(c *gc.C) {
	testJujuHome := c.MkDir()
	defer osenv.SetJujuHome(osenv.SetJujuHome(testJujuHome))
	envPath := osenv.JujuHomePath("environments.yaml")
	c.Assert(envPath, gc.Equals, filepath.Join(testJujuHome, "environments.yaml"))
}