Merge lp:~themue/juju-core/016-juju-home into lp:~juju/juju-core/trunk

[Frank Mueller]

config: added functions to access juju home

This first CL introduces functions for the access to
$JUJU_HOME - if set - or $HOME/.juju as fallback. The
functions return the directory, allow to create a path
to a file/dir in it, set it for testing purposes and
restore it afterwards. A second CL will then migrate
all manual access to $HOME/.juju today to the usage
of the new API.

https://codereview.appspot.com/7774044/

[Dimiter Naydenov (dimitern)]

LGTM with a trivial suggestion.

https://codereview.appspot.com/7774044/diff/1/environs/config/home_test.go
File environs/config/home_test.go (right):

https://codereview.appspot.com/7774044/diff/1/environs/config/home_test.go#newcode26
environs/config/home_test.go:26: config.RestoreJujuHome()
probably you don't need this in both setup and teardown

https://codereview.appspot.com/7774044/

[William Reade (fwereade)]

LGTM

https://codereview.appspot.com/7774044/

=== added file 'environs/config/home.go'
--- environs/config/home.go	1970-01-01 00:00:00 +0000
+++ environs/config/home.go	2013-03-18 10:29:22 +0000
@@ -0,0 +1,56 @@
+package config
+
+import (
+	"os"
+	"path/filepath"
+	"sync"
+)
+
+// jujuHome stores the path to the juju configuration
+// folder defined by $JUJU_HOME or default ~/.juju.
+var (
+	jujuHomeMu sync.Mutex
+	jujuHome   string
+)
+
+func init() {
+	RestoreJujuHome()
+}
+
+// JujuHome returns the current juju home.
+func JujuHome() string {
+	return jujuHome
+}
+
+// JujuHomePath returns the path to a file in the
+// current juju home.
+func JujuHomePath(names ...string) string {
+	all := append([]string{jujuHome}, names...)
+	return filepath.Join(all...)
+}
+
+// SetTestJujuHome allows to set the value of juju home for test
+// purposes. It returns the current juju home.
+func SetTestJujuHome(home string) string {
+	jujuHomeMu.Lock()
+	defer jujuHomeMu.Unlock()
+
+	current := jujuHome
+	jujuHome = home
+	return current
+}
+
+// RestoreJujuHome (re)initializes the juju home after it may
+// have been changed for testing purposes. It returns the
+// juju home.
+func RestoreJujuHome() string {
+	jujuHomeMu.Lock()
+	defer jujuHomeMu.Unlock()
+
+	jujuHome = os.Getenv("JUJU_HOME")
+	if jujuHome == "" {
+		home := os.Getenv("HOME")
+		jujuHome = filepath.Join(home, ".juju")
+	}
+	return jujuHome
+}
 
=== added file 'environs/config/home_test.go'
--- environs/config/home_test.go	1970-01-01 00:00:00 +0000
+++ environs/config/home_test.go	2013-03-18 10:29:22 +0000
@@ -0,0 +1,65 @@
+package config_test
+
+import (
+	. "launchpad.net/gocheck"
+	"os"
+	"path/filepath"
+
+	"launchpad.net/juju-core/environs/config"
+)
+
+type JujuHomeSuite struct {
+	origJujuHome string
+}
+
+var _ = Suite(&JujuHomeSuite{})
+
+func (s *JujuHomeSuite) SetUpSuite(c *C) {
+	s.origJujuHome = config.JujuHome()
+}
+
+func (s *JujuHomeSuite) TearDownSuite(c *C) {
+	config.RestoreJujuHome()
+}
+
+func (s *JujuHomeSuite) SetUpTest(c *C) {
+	config.RestoreJujuHome()
+}
+
+func (s *JujuHomeSuite) TearDownTest(c *C) {
+	err := os.Setenv("JUJU_HOME", s.origJujuHome)
+	c.Assert(err, IsNil)
+}
+
+func (s *JujuHomeSuite) TestStandardHome(c *C) {
+	home := os.Getenv("HOME")
+	err := os.Setenv("JUJU_HOME", "")
+	c.Assert(err, IsNil)
+	jujuHome := config.RestoreJujuHome()
+	newJujuHome := filepath.Join(home, ".juju")
+	c.Assert(jujuHome, Equals, newJujuHome)
+	jujuHome = config.JujuHome()
+	c.Assert(jujuHome, Equals, newJujuHome)
+	testJujuHome := c.MkDir()
+	err = os.Setenv("JUJU_HOME", testJujuHome)
+	jujuHome = config.RestoreJujuHome()
+	c.Assert(jujuHome, Equals, testJujuHome)
+	jujuHome = config.JujuHome()
+	c.Assert(jujuHome, Equals, testJujuHome)
+}
+
+func (s *JujuHomeSuite) TestHomePath(c *C) {
+	envPath := config.JujuHomePath("environments.yaml")
+	c.Assert(envPath, Equals, filepath.Join(s.origJujuHome, "environments.yaml"))
+}
+
+func (s *JujuHomeSuite) TestTestHome(c *C) {
+	jujuHome := config.JujuHome()
+	testJujuHome := c.MkDir()
+	origJujuHome := config.SetTestJujuHome(testJujuHome)
+	c.Assert(jujuHome, Equals, origJujuHome)
+	jujuHome = config.JujuHome()
+	c.Assert(jujuHome, Equals, testJujuHome)
+	jujuHome = config.RestoreJujuHome()
+	c.Assert(jujuHome, Equals, origJujuHome)
+}