Lookup drivers in a fallback package "site-opensvc" if not found in "…

…drivers"

And make "bin/om" honor the PYTHONPATH set in /etc/default/opensvc, in case
the site-opensvc package is not in a standard location.

bin/om

@@ -101,7 +101,7 @@ main() {
 	test -z "$SUDO" && SUDO=env || SUDO="$SUDO OSVC_NAMESPACE=$OSVC_NAMESPACE"
 	if test -n "$KIND"
 	then
-		$SUDO PYTHONPATH="$OSVC_ROOT_PATH" $INTER $OSVC_PYTHON_ARGS -m opensvc $KIND "$@"
+		$SUDO PYTHONPATH="$OSVC_ROOT_PATH:$PYTHONPATH" $INTER $OSVC_PYTHON_ARGS -m opensvc $KIND "$@"
 		return $?
 	fi
 	case $1 in
@@ -110,7 +110,7 @@ main() {
 		exit 1
 		;;
 	*)
-		$SUDO PYTHONPATH="$OSVC_ROOT_PATH" $INTER $OSVC_PYTHON_ARGS -m opensvc "$@"
+		$SUDO PYTHONPATH="$OSVC_ROOT_PATH:$PYTHONPATH" $INTER $OSVC_PYTHON_ARGS -m opensvc "$@"
 		;;
 	esac
 }

opensvc/utilities/drivers.py

@@ -5,6 +5,13 @@
 
 
 def driver_import(*args, **kwargs):
+    try:
+        return _driver_import(*args, **kwargs)
+    except ImportError as exc:
+        kwargs["head"] = "site-opensvc.drivers"
+        return _driver_import(*args, **kwargs)
+
+def _driver_import(*args, head="drivers", fallback=True, initial_modname=None):
     def fmt_element(s):
         if s is None:
             return ""
@@ -14,7 +21,7 @@ def fmt_element(s):
         return s.lower().replace("-", "")
 
     def fmt_modname(args):
-        l = ["drivers"]
+        l = [head]
         for i, e in enumerate(args):
             if e == "":
                 continue
@@ -35,17 +42,19 @@ def import_mod(modname):
                 pass
 
     modname = fmt_modname(args)
-    mod = import_mod(modname)
+    if not initial_modname:
+        initial_modname = modname
 
+    mod = import_mod(modname)
     if mod:
+        if args[0] == "resource" and not hasattr(mod, "adder"):
+            raise ImportError("no module found: %s" % initial_modname)
         return mod
-    if not kwargs.get("head"):
-        kwargs["head"] = modname
-    if kwargs.get("fallback", True) and len(args) > 2:
+    if fallback and len(args) > 2:
         args = args[:-1]
-        return driver_import(*args, **kwargs)
+        return _driver_import(*args, fallback=fallback, initial_modname=initial_modname)
     else:
-        raise ImportError("no module found: %s" % kwargs["head"])
+        raise ImportError("no module found: %s" % initial_modname)
 
 
 def iter_drivers(groups=None):