Merge "Use null backend when cache is disabled"

grafana_dashboards/builder.py

@@ -25,11 +25,12 @@ LOG = logging.getLogger(__name__)
 class Builder(object):
 
     def __init__(self, config):
+        self.cache = Cache(
+            config.get('cache', 'cachedir'),
+            config.getboolean('cache', 'enabled'))
         self.grafana = Grafana(
             config.get('grafana', 'apikey'), config.get('grafana', 'url'))
         self.parser = YamlParser()
-        self.cache_enabled = config.getboolean('cache', 'enabled')
-        self.cache = Cache(config.get('cache', 'cachedir'))
 
     def delete_dashboard(self, path):
         self.load_files(path)
@@ -58,7 +59,7 @@ class Builder(object):
         LOG.info('Number of dashboards generated: %d', len(dashboards))
         for name in dashboards:
             data, md5 = self.parser.get_dashboard(name)
-            if self.cache.has_changed(name, md5) or not self.cache_enabled:
+            if self.cache.has_changed(name, md5):
                 self.grafana.dashboard.create(name, data, overwrite=True)
                 self.cache.set(name, md5)
             else:

grafana_dashboards/cache.py

@@ -22,16 +22,19 @@ LOG = logging.getLogger(__name__)
 
 class Cache(object):
 
-    def __init__(self, cachedir):
+    def __init__(self, cachedir, enabled=True):
-        cache_dir = self._get_cache_dir(cachedir)
+        if enabled:
-        filename = os.path.join(cache_dir, 'cache.dbm')
+            backend = 'dogpile.cache.dbm'
-        LOG.debug('Using cache: %s' % filename)
+            cache_dir = self._get_cache_dir(cachedir)
-        self.region = make_region().configure(
+            filename = os.path.join(cache_dir, 'cache.dbm')
-            'dogpile.cache.dbm',
+            LOG.debug('Using cache: %s' % filename)
-            arguments={
+            arguments = {
                 'filename': filename,
             }
-        )
+        else:
+            backend = 'dogpile.cache.null'
+            arguments = {}
+        self.region = make_region().configure(backend, arguments=arguments)
 
     def get(self, title):
         res = self.region.get(title)

tests/test_cache.py

@@ -22,39 +22,59 @@ class TestCaseCache(TestCase):
         'hello-world': '2095312189753de6ad47dfe20cbe97ec',
     }
 
-    def setUp(self):
-        super(TestCaseCache, self).setUp()
-        cachedir = self.config.get('cache', 'cachedir')
-        self.storage = cache.Cache(cachedir)
-
     def test_cache_has_changed(self):
-        res = self.storage.has_changed(
+        storage = cache.Cache(self.config.get('cache', 'cachedir'))
+        res = storage.has_changed(
             'hello-world', self.dashboard['hello-world'])
         self.assertTrue(res)
-        self.storage.set('hello-world', self.dashboard['hello-world'])
+        storage.set('hello-world', self.dashboard['hello-world'])
-        res = self.storage.has_changed(
+        res = storage.has_changed(
             'hello-world', self.dashboard['hello-world'])
         self.assertFalse(res)
 
+    def test_cache_disabled_has_changed(self):
+        storage = cache.Cache(self.config.get('cache', 'cachedir'), False)
+        res = storage.has_changed(
+            'hello-world', self.dashboard['hello-world'])
+        self.assertTrue(res)
+        # Set a second time and confirm cache has_changed is True.
+        storage.set('hello-world', self.dashboard['hello-world'])
+        res = storage.has_changed(
+            'hello-world', self.dashboard['hello-world'])
+        self.assertTrue(res)
+
     def test_cache_get_empty(self):
-        self.assertEqual(self.storage.get('empty'), None)
+        storage = cache.Cache(self.config.get('cache', 'cachedir'))
+        self.assertEqual(storage.get('empty'), None)
+
+    def test_cache_disabled_get_empty(self):
+        storage = cache.Cache(self.config.get('cache', 'cachedir'), False)
+        self.assertEqual(storage.get('empty'), None)
 
     def test_cache_set_multiple(self):
-        self.storage.set('hello-world', self.dashboard['hello-world'])
+        storage = cache.Cache(self.config.get('cache', 'cachedir'))
+        storage.set('hello-world', self.dashboard['hello-world'])
         self.assertEqual(
-            self.storage.get('hello-world'), self.dashboard['hello-world'])
+            storage.get('hello-world'), self.dashboard['hello-world'])
         dashboard = {
             'foobar': '14758f1afd44c09b7992073ccf00b43d'
         }
         dashboard['hello-world'] = self.dashboard['hello-world']
 
-        self.storage.set('foobar', dashboard['foobar'])
+        storage.set('foobar', dashboard['foobar'])
-        self.assertEqual(self.storage.get('foobar'), dashboard['foobar'])
+        self.assertEqual(storage.get('foobar'), dashboard['foobar'])
         # Make sure hello-world is still valid.
         self.assertEqual(
-            self.storage.get('hello-world'), self.dashboard['hello-world'])
+            storage.get('hello-world'), self.dashboard['hello-world'])
 
     def test_cache_set_single(self):
-        self.storage.set('hello-world', self.dashboard['hello-world'])
+        storage = cache.Cache(self.config.get('cache', 'cachedir'))
+        storage.set('hello-world', self.dashboard['hello-world'])
         self.assertEqual(
-            self.storage.get('hello-world'), self.dashboard['hello-world'])
+            storage.get('hello-world'), self.dashboard['hello-world'])
+
+    def test_cache_disabled_set_single(self):
+        storage = cache.Cache(self.config.get('cache', 'cachedir'), False)
+        storage.set('hello-world', self.dashboard['hello-world'])
+        # Make sure cache is empty
+        self.assertEqual(storage.get('hello-world'), None)