Refactor common parts from cmd to wrapper

This is needed to allow daemon reuse these parts and be plugged in
clearly.

Change-Id: I01e020ae6f185faa446c715cf9a6b0c082260e13

oslo/rootwrap/cmd.py

@@ -33,10 +33,6 @@
 from __future__ import print_function
 
 import logging
-import os
-import pwd
-import signal
-import subprocess
 import sys
 
 from six import moves
@@ -49,12 +45,6 @@ RC_BADCONFIG = 97
 RC_NOEXECFOUND = 96
 
 
-def _subprocess_setup():
-    # Python installs a SIGPIPE handler by default. This is usually not what
-    # non-Python subprocesses expect.
-    signal.signal(signal.SIGPIPE, signal.SIG_DFL)
-
-
 def _exit_error(execname, message, errorcode, log=True):
     print("%s: %s" % (execname, message), file=sys.stderr)
     if log:
@@ -62,15 +52,6 @@ def _exit_error(execname, message, errorcode, log=True):
     sys.exit(errorcode)
 
 
-def _getlogin():
-    try:
-        return os.getlogin()
-    except OSError:
-        return (os.getenv('USER') or
-                os.getenv('USERNAME') or
-                os.getenv('LOGNAME'))
-
-
 def main():
     # Split arguments, require at least a command
     execname = sys.argv.pop(0)
@@ -97,27 +78,22 @@ def main():
                              config.syslog_log_facility,
                              config.syslog_log_level)
 
-    # Execute command if it matches any of the loaded filters
     filters = wrapper.load_filters(config.filters_path)
-    try:
-        filtermatch = wrapper.match_filter(filters, userargs,
-                                           exec_dirs=config.exec_dirs)
-        if filtermatch:
-            command = filtermatch.get_command(userargs,
-                                              exec_dirs=config.exec_dirs)
-            if config.use_syslog:
-                logging.info("(%s > %s) Executing %s (filter match = %s)" % (
-                    _getlogin(), pwd.getpwuid(os.getuid())[0],
-                    command, filtermatch.name))
+    run_one_command(execname, config, filters, userargs)
 
-            obj = subprocess.Popen(command,
-                                   stdin=sys.stdin,
-                                   stdout=sys.stdout,
-                                   stderr=sys.stderr,
-                                   preexec_fn=_subprocess_setup,
-                                   env=filtermatch.get_environment(userargs))
-            obj.wait()
-            sys.exit(obj.returncode)
+
+def run_one_command(execname, config, filters, userargs):
+    # Execute command if it matches any of the loaded filters
+    try:
+        obj = wrapper.start_subprocess(
+            filters, userargs,
+            exec_dirs=config.exec_dirs,
+            log=config.use_syslog,
+            stdin=sys.stdin,
+            stdout=sys.stdout,
+            stderr=sys.stderr)
+        obj.wait()
+        sys.exit(obj.returncode)
 
     except wrapper.FilterMatchNotExecutable as exc:
         msg = ("Executable not found: %s (filter match = %s)"

oslo/rootwrap/wrapper.py

@@ -16,6 +16,9 @@
 import logging
 import logging.handlers
 import os
+import pwd
+import signal
+import subprocess
 
 from six import moves
 
@@ -170,3 +173,34 @@ def match_filter(filter_list, userargs, exec_dirs=None):
 
     # No filter matched
     raise NoFilterMatched()
+
+
+def _subprocess_setup():
+    # Python installs a SIGPIPE handler by default. This is usually not what
+    # non-Python subprocesses expect.
+    signal.signal(signal.SIGPIPE, signal.SIG_DFL)
+
+
+def _getlogin():
+    try:
+        return os.getlogin()
+    except OSError:
+        return (os.getenv('USER') or
+                os.getenv('USERNAME') or
+                os.getenv('LOGNAME'))
+
+
+def start_subprocess(filter_list, userargs, exec_dirs=[], log=False, **kwargs):
+    filtermatch = match_filter(filter_list, userargs, exec_dirs)
+
+    command = filtermatch.get_command(userargs, exec_dirs)
+    if log:
+        logging.info("(%s > %s) Executing %s (filter match = %s)" % (
+            _getlogin(), pwd.getpwuid(os.getuid())[0],
+            command, filtermatch.name))
+
+    obj = subprocess.Popen(command,
+                           preexec_fn=_subprocess_setup,
+                           env=filtermatch.get_environment(userargs),
+                           **kwargs)
+    return obj

tests/test_rootwrap.py

@@ -23,7 +23,6 @@ import mock
 from six import moves
 import testtools
 
-from oslo.rootwrap import cmd
 from oslo.rootwrap import filters
 from oslo.rootwrap import wrapper
 
@@ -437,7 +436,7 @@ class RootwrapTestCase(testtools.TestCase):
     def test_getlogin(self):
         with mock.patch('os.getlogin') as os_getlogin:
             os_getlogin.return_value = 'foo'
-            self.assertEqual(cmd._getlogin(), 'foo')
+            self.assertEqual(wrapper._getlogin(), 'foo')
 
     def test_getlogin_bad(self):
         with mock.patch('os.getenv') as os_getenv:
@@ -445,7 +444,7 @@ class RootwrapTestCase(testtools.TestCase):
                 os_getenv.side_effect = [None, None, 'bar']
                 os_getlogin.side_effect = OSError(
                     '[Errno 22] Invalid argument')
-                self.assertEqual(cmd._getlogin(), 'bar')
+                self.assertEqual(wrapper._getlogin(), 'bar')
                 os_getlogin.assert_called_once_with()
                 self.assertEqual(os_getenv.call_count, 3)