func (*SymlinkSuite) TestReplace(c *gc.C) {
target, err := symlink.GetLongPathAsString(c.MkDir())
c.Assert(err, gc.IsNil)
target_second, err := symlink.GetLongPathAsString(c.MkDir())
c.Assert(err, gc.IsNil)
link := filepath.Join(target, "link")
_, err = os.Stat(target)
c.Assert(err, gc.IsNil)
_, err = os.Stat(target_second)
c.Assert(err, gc.IsNil)
err = symlink.New(target, link)
c.Assert(err, gc.IsNil)
link_target, err := symlink.Read(link)
c.Assert(err, gc.IsNil)
c.Assert(link_target, gc.Equals, filepath.FromSlash(target))
err = symlink.Replace(link, target_second)
c.Assert(err, gc.IsNil)
link_target, err = symlink.Read(link)
c.Assert(err, gc.IsNil)
c.Assert(link_target, gc.Equals, filepath.FromSlash(target_second))
}
// ChangeAgentTools atomically replaces the agent-specific symlink
// under dataDir so it points to the previously unpacked
// version vers. It returns the new tools read.
func ChangeAgentTools(dataDir string, agentName string, vers version.Binary) (*coretools.Tools, error) {
tools, err := ReadTools(dataDir, vers)
if err != nil {
return nil, err
}
// build absolute path to toolsDir. Windows implementation of symlink
// will check for the existance of the source file and error if it does
// not exists. This is a limitation of junction points (symlinks) on NTFS
toolPath := ToolsDir(dataDir, tools.Version.String())
toolsDir := ToolsDir(dataDir, agentName)
err = symlink.Replace(toolsDir, toolPath)
if err != nil {
return nil, fmt.Errorf("cannot replace tools directory: %s", err)
}
return tools, nil
}
// updateBackupMachineTag updates the paths that are stored in the backup
// to the current machine. This path is tied, among other factors, to the
// machine tag.
// Eventually this will change: when backups hold relative paths.
func updateBackupMachineTag(oldTag, newTag names.Tag) error {
oldTagString := oldTag.String()
newTagString := newTag.String()
if oldTagString == newTagString {
return nil
}
oldTagPath := path.Join(agent.DefaultPaths.DataDir, oldTagString)
newTagPath := path.Join(agent.DefaultPaths.DataDir, newTagString)
oldToolsDir := tools.ToolsDir(agent.DefaultPaths.DataDir, oldTagString)
oldLink, err := filepath.EvalSymlinks(oldToolsDir)
os.Rename(oldTagPath, newTagPath)
newToolsDir := tools.ToolsDir(agent.DefaultPaths.DataDir, newTagString)
newToolsPath := strings.Replace(oldLink, oldTagPath, newTagPath, -1)
err = symlink.Replace(newToolsDir, newToolsPath)
return errors.Annotatef(err, "cannot set the new tools path")
}