Adding vg_check from the maas plugins

This change adds the volume group check from the
maas plugins, and also adds a cli helper to run bash command.

Change-Id: I303a843b0abaea721758e182a9c8f3e2db33e85d
Signed-off-by: Michael Rice <michael.rice@rackspace.com>
Signed-off-by: Kevin Carter <kevin.carter@rackspace.com>

monitorstack/plugins/vg_check.py

@@ -0,0 +1,71 @@
+# Copyright 2017, Michael Rice <michael@michaelrice.org>
+#
+# 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 platform
+
+import click
+
+from monitorstack import utils
+from monitorstack.cli import pass_context
+from monitorstack.utils.cli import run_command
+
+DOC = """Check a given volume group"""
+COMMAND_NAME = 'vg_check'
+
+
+@click.command(COMMAND_NAME, short_help=DOC)
+@click.option('--volume_group', nargs=1, type=str, required=True)
+@pass_context
+def cli(ctx, volume_group):
+    """
+    Given volume group name get the total size and free space
+
+    :param ctx: Click context
+    :param volume_group: Name of volume group
+    :type volume_group: str
+    :return:
+    """
+    exit_code, total_size, free = check_volgrp(volume_group)
+    output = {
+        'exit_code': exit_code,
+        'measurement_name': COMMAND_NAME,
+        'meta': {
+            'platform': platform.platform(),
+        }
+    }
+    if exit_code == 0:
+        output['message'] = '{} check for volume group {} is ok'.format(
+            COMMAND_NAME, volume_group)
+        output['variables'] = {
+            'vg_{}_total_size_M'.format(volume_group): total_size,
+            'vg_{}_free_M'.format(volume_group): free,
+            'vg_{}_used_M'.format(volume_group): total_size - free
+        }
+    if exit_code != 0:
+        # if exit_code is not 0 then 'free' actually has our error output.
+        # and with py3 it is bytes so we convert to str first.
+        output['message'] = '{} for {} failed -- {}'.format(
+            COMMAND_NAME, volume_group, utils.log_exception(str(free))
+        )
+    return output
+
+
+def check_volgrp(name):
+    command = ('vgs {} --noheadings --units M '
+               '--nosuffix -o vg_size,vg_free'.format(name))
+    retcode, output, err = run_command(command)
+    if retcode != 0:
+        return retcode, output, err
+    totalsize, free = [int(float(x)) for x in output.split()]
+    return retcode, totalsize, free

monitorstack/utils/cli.py

@@ -0,0 +1,26 @@
+# Copyright 2017, Michael Rice <michael@michaelrice.org>
+#
+# 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 shlex
+import subprocess
+
+
+def run_command(arg):
+    proc = subprocess.Popen(shlex.split(arg),
+                            stdout=subprocess.PIPE,
+                            stderr=subprocess.PIPE,
+                            shell=False)
+
+    out, err = proc.communicate()
+    ret = proc.returncode
+    return ret, out, err

tests/__init__.py

@@ -31,7 +31,8 @@ def runner(module, extra_args=None):
     """
     _runner = CliRunner()
     args = [
-        '-f', 'json',
+        '-f',
+        'json',
         module
     ]
     if extra_args:

tests/unit/__init__.py

@@ -34,3 +34,13 @@ def read_config():
 def fake_version_info(major, minor, serial):
     """Return tuple for fake python version info."""
     return major, minor, serial
+
+
+class FakePopen(object):
+    """Fake Shell Commands."""
+    def __init__(self, return_code=0, *args, **kwargs):
+        self.returncode = return_code
+
+    @staticmethod
+    def communicate():
+        return 'stdout', 'stderr'

tests/unit/test_cli_utils.py

@@ -0,0 +1,56 @@
+# Copyright 2018, Kevin Carter <kevin@cloudnull.com>
+#
+# 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.
+"""Tests for the cli utils plugin."""
+
+import unittest
+
+import mock
+
+from monitorstack.utils import cli
+
+import tests  # Import the test base module
+
+
+class TestCliUtils(unittest.TestCase):
+    """Tests for the utilities."""
+
+    def setUp(self):
+        """Setup the test."""
+        # load the base class for these tests.
+        self.communicate_patched = mock.patch(
+            'monitorstack.utils.cli.subprocess.Popen'
+        )
+        self.communicate = self.communicate_patched.start()
+
+    def tearDown(self):
+        """Tear down the test."""
+        self.communicate_patched.stop()
+
+    def test_run_command_success(self):
+        self.communicate.return_value = tests.unit.FakePopen()
+        ret, out, err = cli.run_command(
+            arg='test_command'
+        )
+        self.assertEqual(out, 'stdout')
+        self.assertEqual(ret, 0)
+
+    def test_run_command_fail(self):
+        self.communicate.return_value = tests.unit.FakePopen(
+            return_code=1
+        )
+        ret, out, err = cli.run_command(
+            arg='test_command'
+        )
+        self.assertEqual(err, 'stderr')
+        self.assertEqual(ret, 1)

tests/unit/test_plugin_kvm.py

@@ -13,26 +13,12 @@
 # limitations under the License.
 """Tests for the KVM plugin."""
 
-import json
 import sys
 import unittest
 
-from click.testing import CliRunner
-
-from monitorstack.cli import cli
-
 import tests.unit  # Import the test base module
 
 
-def _runner(module):
-    runner = CliRunner()
-    result = runner.invoke(cli, ['-f', 'json', module])
-    try:
-        return json.loads(result.output)
-    except Exception:
-        return result.exception
-
-
 class LibvirtStub(object):
     """Stubbed libvirt class."""
 
@@ -91,7 +77,7 @@ class TestKvm(unittest.TestCase):
 
     def test_run_success(self):
         """Ensure the run() method works."""
-        result = _runner('kvm')
+        result = tests.runner('kvm')
         variables = result['variables']
         meta = result['meta']
         assert 'kvm_vms' in variables

tests/unit/test_plugin_vg_check.py

@@ -0,0 +1,76 @@
+# Copyright 2017, Michael Rice <michael@michaelrice.org>
+#
+# 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 unittest
+
+import mock
+
+from monitorstack.plugins import vg_check
+
+import tests.unit  # Import the test base module
+
+
+class VolumeGroupTestCases(unittest.TestCase):
+
+    def setUp(self):
+        """Setup the test."""
+        # load the base class for these tests.
+        self.communicate_patched = mock.patch(
+            'monitorstack.utils.cli.subprocess.Popen'
+        )
+        self.communicate = self.communicate_patched.start()
+
+    def tearDown(self):
+        """Tear down the test."""
+        self.communicate_patched.stop()
+
+    @mock.patch("monitorstack.utils.cli.subprocess")
+    def test_check_volgrp_returns_with_vg_not_found(self, mock_path):
+        """
+        When the volume group is not found an exit status code of 5 is
+        returned by the system. When a non 0 is returned the expected
+        result from this call is is an error message with a blank total
+        """
+        mock_path.Popen.return_value.returncode = 5
+        mock_path.Popen.return_value.communicate.return_value = \
+            ("", "Volume group foo not found")
+        ret_code, total, free = vg_check.check_volgrp("foo")
+        assert ret_code == 5
+        assert total == ""
+        assert free == "Volume group foo not found"
+
+
+class TestVolumeGroup(object):
+    def test_cli_would_exec_command(self, monkeypatch):
+        def mock_get_vgs(name):
+            """Mock the check_volgrp() method."""
+            return 0, 100, 99
+
+        monkeypatch.setattr(
+            vg_check,
+            'check_volgrp',
+            mock_get_vgs
+        )
+
+        result = tests.runner(
+            'vg_check',
+            extra_args=['--volume_group', 'test']
+        )
+        variables = result['variables']
+        assert 'vg_test_used_M' in variables
+        assert variables['vg_test_used_M'] == 1
+        assert 'vg_test_free_M' in variables
+        assert variables['vg_test_free_M'] == 99
+        assert 'vg_test_total_size_M' in variables
+        assert variables['vg_test_total_size_M'] == 100