Merge pull request #1585 from tseaver/logging-metric_exists

Add 'Metrics.exists' API wrapper.

Author: tseaver

gcloud/logging/metric.py

@@ -14,6 +14,8 @@
 
 """Define Logging API Metrics."""
 
+from gcloud.exceptions import NotFound
+
 
 class Metric(object):
     """Metrics represent named filters for log entries.
@@ -93,3 +95,22 @@ def create(self, client=None):
         if self.description:
             data['description'] = self.description
         client.connection.api_request(method='PUT', path=self.path, data=data)
+
+    def exists(self, client=None):
+        """API call:  test for the existence of the metric via a GET request
+
+        See
+        https://cloud.google.com/logging/docs/api/ref_v2beta1/rest/v2beta1/projects.metrics/get
+
+        :type client: :class:`gcloud.logging.client.Client` or ``NoneType``
+        :param client: the client to use.  If not passed, falls back to the
+                       ``client`` stored on the current metric.
+        """
+        client = self._require_client(client)
+
+        try:
+            client.connection.api_request(method='GET', path=self.path)
+        except NotFound:
+            return False
+        else:
+            return True

gcloud/logging/test_metric.py

@@ -93,6 +93,31 @@ def test_create_w_alternate_client(self):
         self.assertEqual(req['path'], '/%s' % FULL)
         self.assertEqual(req['data'], RESOURCE)
 
+    def test_exists_miss_w_bound_client(self):
+        FULL = 'projects/%s/metrics/%s' % (self.PROJECT, self.METRIC_NAME)
+        conn = _Connection()
+        CLIENT = _Client(project=self.PROJECT, connection=conn)
+        metric = self._makeOne(self.METRIC_NAME, self.FILTER, client=CLIENT)
+        self.assertFalse(metric.exists())
+        self.assertEqual(len(conn._requested), 1)
+        req = conn._requested[0]
+        self.assertEqual(req['method'], 'GET')
+        self.assertEqual(req['path'], '/%s' % FULL)
+
+    def test_exists_hit_w_alternate_client(self):
+        FULL = 'projects/%s/metrics/%s' % (self.PROJECT, self.METRIC_NAME)
+        conn1 = _Connection({'name': FULL})
+        CLIENT1 = _Client(project=self.PROJECT, connection=conn1)
+        conn2 = _Connection({'name': FULL})
+        CLIENT2 = _Client(project=self.PROJECT, connection=conn2)
+        metric = self._makeOne(self.METRIC_NAME, self.FILTER, client=CLIENT1)
+        self.assertTrue(metric.exists(client=CLIENT2))
+        self.assertEqual(len(conn1._requested), 0)
+        self.assertEqual(len(conn2._requested), 1)
+        req = conn2._requested[0]
+        self.assertEqual(req['method'], 'GET')
+        self.assertEqual(req['path'], '/%s' % FULL)
+
 
 class _Connection(object):