// Stage causes subsequent calls to Deploy to deploy the supplied charm.
func (d *Deployer) Stage(bun *charm.Bundle, url *charm.URL) error {
// Read present state of current.
if err := os.MkdirAll(d.path, 0755); err != nil {
return err
}
defer d.collectOrphans()
srcExists, err := d.current.Exists()
if err != nil {
return err
}
if srcExists {
prevURL, err := ReadCharmURL(d.current)
if err != nil {
return err
}
if *url == *prevURL {
return nil
}
}
// Prepare a fresh repository for the update, using current's history
// if it exists.
path, err := d.newDir("update")
if err != nil {
return err
}
var repo *GitDir
if srcExists {
repo, err = d.current.Clone(path)
} else {
repo = NewGitDir(path)
err = repo.Init()
}
if err != nil {
return err
}
// Write the desired new state and commit.
if err = bun.ExpandTo(path); err != nil {
return err
}
if err = WriteCharmURL(repo, url); err != nil {
return err
}
if err = repo.Snapshotf("Imported charm %q from %q.", url, bun.Path); err != nil {
return err
}
// Atomically rename fresh repository to current.
tmplink := filepath.Join(path, "tmplink")
if err = os.Symlink(path, tmplink); err != nil {
return err
}
return os.Rename(tmplink, d.current.Path())
}
