Add memcache snippets (#295)

Author: elibixby

appengine/memcache/snippets/snippets.py

@@ -0,0 +1,54 @@
+# Copyright 2016 Google Inc. All rights reserved.
+#
+# 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.
+
+# [START import]
+from google.appengine.api import memcache
+# [END import]
+
+
+def query_for_data():
+    return 'data'
+
+
+# [START get_data]
+def get_data():
+    data = memcache.get('key')
+    if data is not None:
+        return data
+    else:
+        data = query_for_data()
+        memcache.add('key', data, 60)
+    return data
+# [END get_data]
+
+
+def add_values():
+    # [START add_values]
+    # Add a value if it doesn't exist in the cache
+    # with a cache expiration of 1 hour.
+    memcache.add(key="weather_USA_98105", value="raining", time=3600)
+
+    # Set several values, overwriting any existing values for these keys.
+    memcache.set_multi(
+        {"USA_98115": "cloudy", "USA_94105": "foggy", "USA_94043": "sunny"},
+        key_prefix="weather_",
+        time=3600
+    )
+
+    # Atomically increment an integer value.
+    memcache.set(key="counter", value=0)
+    memcache.incr("counter")
+    memcache.incr("counter")
+    memcache.incr("counter")
+    # [END add_values]

appengine/memcache/snippets/snippets_test.py

@@ -0,0 +1,48 @@
+# Copyright 2016 Google Inc. All rights reserved.
+#
+# 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.
+
+from google.appengine.api import memcache
+from mock import patch
+import snippets
+
+SNIPPET_VALUES = {
+    "weather_USA_98105": "raining",
+    "weather_USA_98115": "cloudy",
+    "weather_USA_94105": "foggy",
+    "weather_USA_94043": "sunny",
+    "counter": 3,
+}
+
+
+@patch('snippets.query_for_data', return_value='data')
+def test_get_data_not_present(query_fn, testbed):
+    data = snippets.get_data()
+    query_fn.assert_called_once_with()
+    assert data == 'data'
+    memcache.delete('key')
+
+
+@patch('snippets.query_for_data', return_value='data')
+def test_get_data_present(query_fn, testbed):
+    memcache.add('key', 'data', 9000)
+    data = snippets.get_data()
+    query_fn.assert_not_called()
+    assert data == 'data'
+    memcache.delete('key')
+
+
+def test_add_values(testbed):
+    snippets.add_values()
+    for key, value in SNIPPET_VALUES.iteritems():
+        assert memcache.get(key) == value