Make utils.execute not overwrite std{in,out,err} args to Popen on retries.

Make utils.execute reject unknown kwargs.

Add a couple of unit tests for utils.execute.

2 files changed, 93 insertions, 10 deletions

diff --git a/nova/tests/test_utils.py b/nova/tests/test_utils.py
index 34a407f1a..e08d229b0 100644
--- a/nova/tests/test_utils.py
+++ b/nova/tests/test_utils.py
@@ -14,11 +14,89 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
+import os
+import tempfile
+
 from nova import test
 from nova import utils
 from nova import exception
 
 
+class ExecuteTestCase(test.TestCase):
+    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, 0755)
+            self.assertRaises(exception.ProcessExecutionError,
+                              utils.execute,
+                              tmpfilename, tmpfilename2, attempts=10,
+                              process_input='foo',
+                              delay_on_retry=False)
+            fp = open(tmpfilename2, 'r+')
+            runs = fp.read()
+            fp.close()
+            self.assertNotEquals(runs.strip(), 'failure', 'stdin did not '
+                                                          'always get passed '
+                                                          'correctly')
+            runs = int(runs.strip())
+            self.assertEquals(runs, 10,
+                              'Ran %d times instead of 10.' % (runs,))
+        finally:
+            os.unlink(tmpfilename)
+            os.unlink(tmpfilename2)
+
+    def test_unknown_kwargs_raises_error(self):
+        self.assertRaises(exception.Error,
+                          utils.execute,
+                          '/bin/true', this_is_not_a_valid_kwarg=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, 0755)
+            utils.execute(tmpfilename,
+                          tmpfilename2,
+                          process_input='foo',
+                          attempts=2)
+        finally:
+            os.unlink(tmpfilename)
+            os.unlink(tmpfilename2)
+
+
 class GetFromPathTestCase(test.TestCase):
     def test_tolerates_nones(self):
         f = utils.get_from_path
diff --git a/nova/utils.py b/nova/utils.py
index 24b8da9ea..499af2039 100644
--- a/nova/utils.py
+++ b/nova/utils.py
@@ -133,13 +133,14 @@ def fetchfile(url, target):
 
 
 def execute(*cmd, **kwargs):
-    process_input = kwargs.get('process_input', None)
-    addl_env = kwargs.get('addl_env', None)
-    check_exit_code = kwargs.get('check_exit_code', 0)
-    stdin = kwargs.get('stdin', subprocess.PIPE)
-    stdout = kwargs.get('stdout', subprocess.PIPE)
-    stderr = kwargs.get('stderr', subprocess.PIPE)
-    attempts = kwargs.get('attempts', 1)
+    process_input = kwargs.pop('process_input', None)
+    addl_env = kwargs.pop('addl_env', None)
+    check_exit_code = kwargs.pop('check_exit_code', 0)
+    delay_on_retry = kwargs.pop('delay_on_retry', True)
+    attempts = kwargs.pop('attempts', 1)
+    if len(kwargs):
+        raise exception.Error(_('Got unknown keyword args '
+                                'to utils.execute: %r') % kwargs)
     cmd = map(str, cmd)
 
     while attempts > 0:
@@ -149,8 +150,11 @@ def execute(*cmd, **kwargs):
             env = os.environ.copy()
             if addl_env:
                 env.update(addl_env)
-            obj = subprocess.Popen(cmd, stdin=stdin,
-                    stdout=stdout, stderr=stderr, env=env)
+            obj = subprocess.Popen(cmd,
+                                   stdin=subprocess.PIPE,
+                                   stdout=subprocess.PIPE,
+                                   stderr=subprocess.PIPE,
+                                   env=env)
             result = None
             if process_input != None:
                 result = obj.communicate(process_input)
@@ -176,7 +180,8 @@ def execute(*cmd, **kwargs):
                 raise
             else:
                 LOG.debug(_("%r failed. Retrying."), cmd)
-                greenthread.sleep(random.randint(20, 200) / 100.0)
+                if delay_on_retry:
+                    greenthread.sleep(random.randint(20, 200) / 100.0)
 
 
 def ssh_execute(ssh, cmd, process_input=None,