Improved Plugin.call() method and added its unit test

ipalib/errors.py

@@ -124,6 +124,14 @@ def _(text):
     return text
 
 
+class SubprocessError(StandardError):
+    def __init__(self, returncode, argv):
+        self.returncode = returncode
+        self.argv = argv
+        StandardError.__init__(self,
+            'return code %d from %r' % (returncode, argv)
+        )
+
 class HandledError(StandardError):
     """
     Base class for errors that can be raised across a remote procedure call.

ipalib/plugable.py

@@ -367,15 +367,22 @@ class Plugin(ReadOnly):
                 assert not hasattr(self, name)
                 setattr(self, name, getattr(api, name))
 
-    def call(self, *args):
+    def call(self, executable, *args):
         """
-        Call an external command via ``subprocess.call``.
+        Call ``executable`` with ``args`` using subprocess.call().
 
-        Returns the exit status of the call.
+        If the call exits with a non-zero exit status,
+        `ipalib.errors.SubprocessError` is raised, from which you can retrieve
+        the exit code by checking the SubprocessError.returncode attribute.
+
+        This method does *not* return what ``executable`` sent to stdout... for
+        that, use `Plugin.callread()`.
         """
-        if hasattr(self, 'log'):
-            self.log.debug('Calling %r', args)
-        return subprocess.call(args)
+        argv = (executable,) + args
+        self.debug('Calling %r', argv)
+        returncode = subprocess.call(argv)
+        if returncode != 0:
+            raise errors.SubprocessError(returncode, argv)
 
     def __repr__(self):
         """

tests/test_ipalib/test_plugable.py

@@ -452,6 +452,18 @@ class test_Plugin(ClassChecker):
         o.finalize()
         assert o.__islocked__()
 
+    def test_call(self):
+        """
+        Test the `ipalib.plugable.Plugin.call` method.
+        """
+        o = self.cls()
+        o.call('/bin/true') is None
+        e = raises(errors.SubprocessError, o.call, '/bin/false')
+        assert str(e) == 'return code %d from %r' % (1, ('/bin/false',))
+        assert e.returncode == 1
+        assert e.argv == ('/bin/false',)
+
+
 
 class test_PluginProxy(ClassChecker):
     """