Added execute util

It is needed to run OS commands. It uses
oslo processutils. It is just a copy of the
same method in openstack/ironic except
using rootwrap was removed.

Change-Id: I2efede22b1fa25febe91879c0fefcdfc7f3d1dd5

ironic_python_agent/tests/utils.py

@@ -0,0 +1,105 @@
+# Copyright 2011 Justin Santa Barbara
+# Copyright 2012 Hewlett-Packard Development Company, L.P.
+#
+#    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.
+
+import os
+import tempfile
+import testtools
+
+from ironic_python_agent.openstack.common import processutils
+from ironic_python_agent import utils
+
+
+class ExecuteTestCase(testtools.TestCase):
+    """This class is a copy of the same class in openstack/ironic."""
+
+    def test_retry_on_failure(self):
+        fd, tmpfilename = tempfile.mkstemp()
+        _, tmpfilename2 = tempfile.mkstemp()
+        try:
+            fp = os.fdopen(fd, 'w+')
+            fp.write('''#!/bin/sh
+# If stdin fails to get passed during one of the runs, make a note.
+if ! grep -q foo
+then
+    echo 'failure' > "$1"
+fi
+# If stdin has failed to get passed during this or a previous run, exit early.
+if grep failure "$1"
+then
+    exit 1
+fi
+runs="$(cat $1)"
+if [ -z "$runs" ]
+then
+    runs=0
+fi
+runs=$(($runs + 1))
+echo $runs > "$1"
+exit 1
+''')
+            fp.close()
+            os.chmod(tmpfilename, 0o755)
+            self.assertRaises(processutils.ProcessExecutionError,
+                              utils.execute,
+                              tmpfilename, tmpfilename2, attempts=10,
+                              process_input='foo',
+                              delay_on_retry=False)
+            fp = open(tmpfilename2, 'r')
+            runs = fp.read()
+            fp.close()
+            self.assertNotEqual(runs.strip(), 'failure', 'stdin did not '
+                                                          'always get passed '
+                                                          'correctly')
+            runs = int(runs.strip())
+            self.assertEqual(10, runs,
+                              'Ran %d times instead of 10.' % (runs,))
+        finally:
+            os.unlink(tmpfilename)
+            os.unlink(tmpfilename2)
+
+    def test_unknown_kwargs_raises_error(self):
+        self.assertRaises(processutils.UnknownArgumentError,
+                          utils.execute,
+                          '/usr/bin/env', 'true',
+                          this_is_not_a_valid_kwarg=True)
+
+    def test_check_exit_code_boolean(self):
+        utils.execute('/usr/bin/env', 'false', check_exit_code=False)
+        self.assertRaises(processutils.ProcessExecutionError,
+                          utils.execute,
+                          '/usr/bin/env', 'false', check_exit_code=True)
+
+    def test_no_retry_on_success(self):
+        fd, tmpfilename = tempfile.mkstemp()
+        _, tmpfilename2 = tempfile.mkstemp()
+        try:
+            fp = os.fdopen(fd, 'w+')
+            fp.write('''#!/bin/sh
+# If we've already run, bail out.
+grep -q foo "$1" && exit 1
+# Mark that we've run before.
+echo foo > "$1"
+# Check that stdin gets passed correctly.
+grep foo
+''')
+            fp.close()
+            os.chmod(tmpfilename, 0o755)
+            utils.execute(tmpfilename,
+                          tmpfilename2,
+                          process_input='foo',
+                          attempts=2)
+        finally:
+            os.unlink(tmpfilename)
+            os.unlink(tmpfilename2)

ironic_python_agent/utils.py

@@ -13,9 +13,16 @@ 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.
 """
+
 import collections
 import ordereddict
 
+from ironic_python_agent.openstack.common import gettextutils as gtu
+from ironic_python_agent.openstack.common import log as logging
+from ironic_python_agent.openstack.common import processutils
+
+LOG = logging.getLogger(__name__)
+
 
 def get_ordereddict(*args, **kwargs):
     """A fix for py26 not having ordereddict."""
@@ -23,3 +30,13 @@ def get_ordereddict(*args, **kwargs):
         return collections.OrderedDict(*args, **kwargs)
     except AttributeError:
         return ordereddict.OrderedDict(*args, **kwargs)
+
+
+def execute(*cmd, **kwargs):
+    """Convenience wrapper around oslo's execute() method."""
+    result = processutils.execute(*cmd, **kwargs)
+    LOG.debug(gtu._('Execution completed, command line is "%s"'),
+              ' '.join(cmd))
+    LOG.debug(gtu._('Command stdout is: "%s"') % result[0])
+    LOG.debug(gtu._('Command stderr is: "%s"') % result[1])
+    return result