worker/apiuniter: Clone uniter, fix imports

worker/apiuniter/tools.go

+// Copyright 2012, 2013 Canonical Ltd.
+// Licensed under the AGPLv3, see LICENCE file for details.
+
+package apiuniter
+
+import (
+        "fmt"
+        "os"
+        "path/filepath"
+
+        "launchpad.net/juju-core/worker/apiuniter/jujuc"
+)
+
+// EnsureJujucSymlinks creates a symbolic link to jujuc within dir for each
+// hook command. If the commands already exist, this operation does nothing.
+func EnsureJujucSymlinks(dir string) (err error) {
+        for _, name := range jujuc.CommandNames() {
+                // The link operation fails when the target already exists,
+                // so this is a no-op when the command names already
+                // exist.
+                err := os.Symlink("./jujud", filepath.Join(dir, name))
+                if err == nil {
+                        continue
+                }
+                // TODO(rog) drop LinkError check when fix is released (see http://codereview.appspot.com/6442080/)
+                if e, ok := err.(*os.LinkError); !ok || !os.IsExist(e.Err) {
+                        return fmt.Errorf("cannot initialize hook commands in %q: %v", dir, err)
+                }
+        }
+        return nil
+}