Move utils.execute to its own module.

Also move the exceptions raised to being local to the executils
module.

Change-Id: Ibb2445f92840b9ce4b52373b0b09adb3d6a4a897

3 files changed, 124 insertions, 88 deletions

diff --git a/openstack/common/exception.py b/openstack/common/exception.py
index ba32da5..4866de2 100644
--- a/openstack/common/exception.py
+++ b/openstack/common/exception.py
@@ -22,18 +22,6 @@ Exceptions common to OpenStack projects
 import logging
 
 
-class ProcessExecutionError(IOError):
-    def __init__(self, stdout=None, stderr=None, exit_code=None, cmd=None,
-                 description=None):
-        if description is None:
-            description = "Unexpected error while running command."
-        if exit_code is None:
-            exit_code = '-'
-        message = "%s\nCommand: %s\nExit code: %s\nStdout: %r\nStderr: %r" % (
-                  description, cmd, exit_code, stdout, stderr)
-        IOError.__init__(self, message)
-
-
 class Error(Exception):
     def __init__(self, message=None):
         super(Error, self).__init__(message)
diff --git a/openstack/common/processutils.py b/openstack/common/processutils.py
new file mode 100644
index 0000000..a21db01
--- /dev/null
+++ b/openstack/common/processutils.py
@@ -0,0 +1,124 @@
+# vim: tabstop=4 shiftwidth=4 softtabstop=4
+
+# Copyright 2011 OpenStack LLC.
+# All Rights Reserved.
+#
+#    Licensed under the Apache License, Version 2.0 (the "License"); you may
+#    not use this file except in compliance with the License. You may obtain
+#    a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+#    License for the specific language governing permissions and limitations
+#    under the License.
+
+"""
+System-level utilities and helper functions.
+"""
+
+import logging
+import random
+import shlex
+
+from eventlet.green import subprocess
+from eventlet import greenthread
+
+from openstack.common.gettextutils import _
+
+
+LOG = logging.getLogger(__name__)
+
+
+class UnknownArgumentError(Exception):
+    def __init__(self, message=None):
+        super(UnknownArgumentError, self).__init__(message)
+
+
+class ProcessExecutionError(Exception):
+    def __init__(self, stdout=None, stderr=None, exit_code=None, cmd=None,
+                 description=None):
+        if description is None:
+            description = "Unexpected error while running command."
+        if exit_code is None:
+            exit_code = '-'
+        message = ("%s\nCommand: %s\nExit code: %s\nStdout: %r\nStderr: %r"
+                   % (description, cmd, exit_code, stdout, stderr))
+        super(ProcessExecutionError, self).__init__(message)
+
+
+def execute(*cmd, **kwargs):
+    """
+    Helper method to execute command with optional retry.
+
+    :cmd                Passed to subprocess.Popen.
+    :process_input      Send to opened process.
+    :check_exit_code    Defaults to 0. Raise executils.ProcessExecutionError
+                        unless program exits with this code.
+    :delay_on_retry     True | False. Defaults to True. If set to True, wait a
+                        short amount of time before retrying.
+    :attempts           How many times to retry cmd.
+    :run_as_root        True | False. Defaults to False. If set to True,
+                        the command is prefixed by the command specified
+                        in the root_helper kwarg.
+    :root_helper        command to prefix all cmd's with
+
+    :raises executils.UnknownArgumentError on receiving unknown arguments
+    :raises executils.ProcessExecutionError
+    """
+
+    process_input = kwargs.pop('process_input', None)
+    check_exit_code = kwargs.pop('check_exit_code', 0)
+    delay_on_retry = kwargs.pop('delay_on_retry', True)
+    attempts = kwargs.pop('attempts', 1)
+    run_as_root = kwargs.pop('run_as_root', False)
+    root_helper = kwargs.pop('root_helper', '')
+    if len(kwargs):
+        raise UnknownArgumentError(_('Got unknown keyword args '
+                                     'to utils.execute: %r') % kwargs)
+    if run_as_root:
+        cmd = shlex.split(root_helper) + list(cmd)
+    cmd = map(str, cmd)
+
+    while attempts > 0:
+        attempts -= 1
+        try:
+            LOG.debug(_('Running cmd (subprocess): %s'), ' '.join(cmd))
+            _PIPE = subprocess.PIPE  # pylint: disable=E1101
+            obj = subprocess.Popen(cmd,
+                                   stdin=_PIPE,
+                                   stdout=_PIPE,
+                                   stderr=_PIPE,
+                                   close_fds=True)
+            result = None
+            if process_input is not None:
+                result = obj.communicate(process_input)
+            else:
+                result = obj.communicate()
+            obj.stdin.close()  # pylint: disable=E1101
+            _returncode = obj.returncode  # pylint: disable=E1101
+            if _returncode:
+                LOG.debug(_('Result was %s') % _returncode)
+                if (isinstance(check_exit_code, int) and
+                    not isinstance(check_exit_code, bool) and
+                        _returncode != check_exit_code):
+                    (stdout, stderr) = result
+                    raise ProcessExecutionError(exit_code=_returncode,
+                                                stdout=stdout,
+                                                stderr=stderr,
+                                                cmd=' '.join(cmd))
+            return result
+        except ProcessExecutionError:
+            if not attempts:
+                raise
+            else:
+                LOG.debug(_('%r failed. Retrying.'), cmd)
+                if delay_on_retry:
+                    greenthread.sleep(random.randint(20, 200) / 100.0)
+        finally:
+            # NOTE(termie): this appears to be necessary to let the subprocess
+            #               call clean something up in between calls, without
+            #               it two execute calls in a row hangs the second one
+            greenthread.sleep(0)
diff --git a/openstack/common/utils.py b/openstack/common/utils.py
index 220b49e..dce62c1 100644
--- a/openstack/common/utils.py
+++ b/openstack/common/utils.py
@@ -62,79 +62,3 @@ def bool_from_string(subject):
         if subject.strip().lower() in ('true', 'on', 'yes', '1'):
             return True
     return False
-
-
-def execute(*cmd, **kwargs):
-    """
-    Helper method to execute command with optional retry.
-
-    :cmd                Passed to subprocess.Popen.
-    :process_input      Send to opened process.
-    :check_exit_code    Defaults to 0. Raise exception.ProcessExecutionError
-                        unless program exits with this code.
-    :delay_on_retry     True | False. Defaults to True. If set to True, wait a
-                        short amount of time before retrying.
-    :attempts           How many times to retry cmd.
-    :run_as_root        True | False. Defaults to False. If set to True,
-                        the command is prefixed by the command specified
-                        in the root_helper kwarg.
-    :root_helper        command to prefix all cmd's with
-
-    :raises exception.Error on receiving unknown arguments
-    :raises exception.ProcessExecutionError
-    """
-
-    process_input = kwargs.pop('process_input', None)
-    check_exit_code = kwargs.pop('check_exit_code', 0)
-    delay_on_retry = kwargs.pop('delay_on_retry', True)
-    attempts = kwargs.pop('attempts', 1)
-    run_as_root = kwargs.pop('run_as_root', False)
-    root_helper = kwargs.pop('root_helper', '')
-    if len(kwargs):
-        raise exception.Error(_('Got unknown keyword args '
-                                'to utils.execute: %r') % kwargs)
-    if run_as_root:
-        cmd = shlex.split(root_helper) + list(cmd)
-    cmd = map(str, cmd)
-
-    while attempts > 0:
-        attempts -= 1
-        try:
-            LOG.debug(_('Running cmd (subprocess): %s'), ' '.join(cmd))
-            _PIPE = subprocess.PIPE  # pylint: disable=E1101
-            obj = subprocess.Popen(cmd,
-                                   stdin=_PIPE,
-                                   stdout=_PIPE,
-                                   stderr=_PIPE,
-                                   close_fds=True)
-            result = None
-            if process_input is not None:
-                result = obj.communicate(process_input)
-            else:
-                result = obj.communicate()
-            obj.stdin.close()  # pylint: disable=E1101
-            _returncode = obj.returncode  # pylint: disable=E1101
-            if _returncode:
-                LOG.debug(_('Result was %s') % _returncode)
-                if (isinstance(check_exit_code, int) and
-                    not isinstance(check_exit_code, bool) and
-                        _returncode != check_exit_code):
-                    (stdout, stderr) = result
-                    raise exception.ProcessExecutionError(
-                        exit_code=_returncode,
-                        stdout=stdout,
-                        stderr=stderr,
-                        cmd=' '.join(cmd))
-            return result
-        except exception.ProcessExecutionError:
-            if not attempts:
-                raise
-            else:
-                LOG.debug(_('%r failed. Retrying.'), cmd)
-                if delay_on_retry:
-                    greenthread.sleep(random.randint(20, 200) / 100.0)
-        finally:
-            # NOTE(termie): this appears to be necessary to let the subprocess
-            #               call clean something up in between calls, without
-            #               it two execute calls in a row hangs the second one
-            greenthread.sleep(0)