Merge lp:~cmars/charm-helpers/add-metricenv into lp:charm-helpers

[Casey Marshall]

Add functions to charmhelpers.core.hookenv related to Juju Metrics (https://jujucharms.com/docs/stable/developer-metrics).

[lp:~cmars/charm-helpers/add-metricenv]

679. By Casey Marshall on 2017-01-31

Add metrics functions to charmhelpers.core.hookenv.

[Chris Holcombe (xfactor973)]

Other than a little nit this looks ok to me.

review: Needs Fixing

[lp:~cmars/charm-helpers/add-metricenv]

680. By Casey Marshall on 2017-02-01

Catch EnvironmentError exception, covers subclasses such as IOError and OSError.

[Casey Marshall (cmars)]

Updated, PTAL

[Marco Ceppi (marcoceppi)]

LGTM

review: Approve

=== modified file 'charmhelpers/core/hookenv.py'
--- charmhelpers/core/hookenv.py	2016-12-16 14:57:13 +0000
+++ charmhelpers/core/hookenv.py	2017-02-01 00:13:09 +0000
@@ -1035,3 +1035,34 @@
     '''
     cmd = ['network-get', '--primary-address', binding]
     return subprocess.check_output(cmd).decode('UTF-8').strip()
+
+
+def add_metric(*args, **kwargs):
+    """Add metric values. Values may be expressed with keyword arguments. For
+    metric names containing dashes, these may be expressed as one or more
+    'key=value' positional arguments. May only be called from the collect-metrics
+    hook."""
+    _args = ['add-metric']
+    _kvpairs = []
+    _kvpairs.extend(args)
+    _kvpairs.extend(['{}={}'.format(k, v) for k, v in kwargs.items()])
+    _args.extend(sorted(_kvpairs))
+    try:
+        subprocess.check_call(_args)
+        return
+    except EnvironmentError as e:
+        if e.errno != errno.ENOENT:
+            raise
+    log_message = 'add-metric failed: {}'.format(' '.join(_kvpairs))
+    log(log_message, level='INFO')
+
+
+def meter_status():
+    """Get the meter status, if running in the meter-status-changed hook."""
+    return os.environ.get('JUJU_METER_STATUS')
+
+
+def meter_info():
+    """Get the meter status information, if running in the meter-status-changed
+    hook."""
+    return os.environ.get('JUJU_METER_INFO')

=== modified file 'tests/core/test_hookenv.py'
--- tests/core/test_hookenv.py	2016-12-16 14:57:13 +0000
+++ tests/core/test_hookenv.py	2017-02-01 00:13:09 +0000
@@ -1663,3 +1663,31 @@
         check_output.side_effect = OSError(2, 'network-get')
         self.assertRaises(NotImplementedError, hookenv.network_get_primary_address,
                           'mybinding')
+
+    @patch('subprocess.check_call')
+    def test_add_metric(self, check_call_):
+        hookenv.add_metric(flips='1.5', flops='2.1')
+        hookenv.add_metric('juju-units=6')
+        hookenv.add_metric('foo-bar=3.333', 'baz-quux=8', users='2')
+        calls = [
+            call(['add-metric', 'flips=1.5', 'flops=2.1']),
+            call(['add-metric', 'juju-units=6']),
+            call(['add-metric', 'baz-quux=8', 'foo-bar=3.333', 'users=2']),
+        ]
+        check_call_.assert_has_calls(calls)
+
+    @patch('subprocess.check_call')
+    @patch.object(hookenv, 'log')
+    def test_add_metric_enoent(self, log, _check_call):
+        _check_call.side_effect = OSError(2, 'fail')
+        hookenv.add_metric(flips='1')
+        log.assert_called_with('add-metric failed: flips=1', level='INFO')
+
+    @patch('charmhelpers.core.hookenv.os')
+    def test_meter_status(self, os_):
+        os_.environ = {
+            'JUJU_METER_STATUS': 'GREEN',
+            'JUJU_METER_INFO': 'all good',
+        }
+        self.assertEqual(hookenv.meter_status(), 'GREEN')
+        self.assertEqual(hookenv.meter_info(), 'all good')