From a6e6c5c7d46c41d578da5ed082269611b262917e Mon Sep 17 00:00:00 2001
From: "Richard S. Imaoka" <richard.s.imaoka@gmail.com>
Date: Sun, 14 Aug 2016 16:56:13 +0900
Subject: [PATCH] Switch between Redis and Memcached via an environment
 variable #37

---
 README.md           | 33 ++++-----------------------------
 app.py              | 15 +++++++--------
 app.yaml            |  5 ++++-
 cache.py            |  8 ++------
 config.json.default |  9 +++++++++
 5 files changed, 26 insertions(+), 44 deletions(-)

diff --git a/README.md b/README.md
index ccf83ce..a0d9aae 100644
--- a/README.md
+++ b/README.md
@@ -29,36 +29,11 @@
 
 GAE doesn't support Redis. So you need to use Memcache instead.
 
-1.  setup
+1.  setup GAE SDK
+
+  - Install [GAE Python SDK](https://cloud.google.com/appengine/downloads)   
 
-  - Install [GAE Python SDK](https://cloud.google.com/appengine/downloads)
-    
-
-2.  In config.json,
-
-   Remove the "REDIS_INFO" section :
-   
-   ```
-       "REDIS_INFO": {
-         ...
-       },
-   ```
-
-   and add the "MEMCACHE" section like below
-
-   ```
-    "MEMCACHE": {
-        "servers" : [
-            {
-                "host": "localhost",
-                "port": "11211"
-            }
-        ],
-        "debug": 0
-    },  
-   ```
-
-3.  start GAE local dev server
+2.  start GAE local dev server
   
     do not forget the last dot (.) in the command
 
diff --git a/app.py b/app.py
index 9a64c29..bd53bd4 100644
--- a/app.py
+++ b/app.py
@@ -38,15 +38,13 @@ def __init__(self, file):
         with open(file, 'r') as f:
             self.cfg = json.load(f)
 
-        for section in ['OCTAV', 'GITHUB', 'GOOGLE_MAP']:
+        for section in ['OCTAV', 'GITHUB', 'REDIS_INFO', 'GOOGLE_MAP']:
             if not self.cfg.get(section):
                 raise Exception( "missing section '" + section + "' in config file '" + file + "'" )
         if self.cfg.get('OCTAV').get('BASE_URI'):
             raise Exception(
                 'DEPRECATED: {"OCTAV":{"BASE_URI"}} in config.json is deprecated.\
  Please use {"OCTAV":{"endpoint"}} instead and remove {"OCTAV":{"BASE_URI"}}.')
-        if self.cfg.get('REDIS_INFO') and self.cfg.get('MEMCACHE'):
-            raise Exception( 'In config.json, do not specify both "REDIS_INFO" and "MEMCACHE". Use only either of them.' )
 
 
     def section(self, name):
@@ -70,14 +68,15 @@ def googlemap_api_key(self):
 
 octav = Octav(**cfg.section('OCTAV'))
 
-if cfg.section('REDIS_INFO'):
+backend = os.getenv('CACHE_BACKEND', 'Redis')
+if backend == 'Redis':
     cache = cache.Redis(**cfg.section('REDIS_INFO'))
-elif cfg.section('MEMCACHE'):
-    cache = cache.Memcache(**cfg.section('MEMCACHE'))
+elif backend == 'Memcached':
+    cache = cache.Memcached(**cfg.section('MEMCACHED'))
 else:
-    raise Exception( 'config.json must specify either of "REDIS_INFO" or "MEMCACHE"' )
+    raise Exception('Unknown backend "%s"' % backend)
 
-twitter = oauth.Init('twitter', 
+twitter = oauth.Init('twitter',
     base_url='https://api.twitter.com/1.1/',
     request_token_url='https://api.twitter.com/oauth/request_token',
     access_token_url='https://api.twitter.com/oauth/access_token',
diff --git a/app.yaml b/app.yaml
index 42ad914..50b122d 100644
--- a/app.yaml
+++ b/app.yaml
@@ -10,4 +10,7 @@ handlers:
 
 libraries:
 - name: jinja2
-  version: latest
\ No newline at end of file
+  version: latest
+
+env_variables:
+  CACHE_BACKEND: 'Memcached'
\ No newline at end of file
diff --git a/cache.py b/cache.py
index ccfb393..f556ff8 100644
--- a/cache.py
+++ b/cache.py
@@ -22,7 +22,7 @@ def get(self, key):
 
         return pickle.loads(thing)
 
-class Memcache:
+class Memcached:
     def __init__(self, servers=[], debug=0):
         if os.getenv('SERVER_SOFTWARE', '').startswith('Google App Engine/') or os.getenv('SERVER_SOFTWARE', '').startswith('Development/'):
             print "GAE memcache used"
@@ -49,9 +49,5 @@ def set(self, key, val, expires=0):
         self.client .set(key, val, expires)
 
     def get(self, key):
-        thing = self.client .get(key)
-        if not thing:
-            return None
-
-        return thing
+        return self.client.get(key)
 
diff --git a/config.json.default b/config.json.default
index 4aea51c..1fde8ae 100644
--- a/config.json.default
+++ b/config.json.default
@@ -8,6 +8,15 @@
         "port": 6379,
         "db": 0
     },
+    "MEMCACHED": {
+        "servers" : [
+            {
+                "host": "localhost",
+                "port": "11211"
+            }
+        ],
+        "debug": 0
+    },
     "OCTAV": {
         "endpoint": "",
         "key": "",