make the prefix for environment variables alterable

docs/sanic/config.md

@@ -29,9 +29,15 @@ In general the convention is to only have UPPERCASE configuration parameters. Th
 
 There are several ways how to load configuration.
 
-### From environment variables.
+### From Environment Variables
 
-Any variables defined with the `SANIC_` prefix will be applied to the sanic config. For example, setting `SANIC_REQUEST_TIMEOUT` will be loaded by the application automatically. You can pass the `load_env` boolean to the Sanic constructor to override that:
+Any variables defined with the `SANIC_` prefix will be applied to the sanic config. For example, setting `SANIC_REQUEST_TIMEOUT` will be loaded by the application automatically and fed into the `REQUEST_TIMEOUT` config variable. You can pass a different prefix to Sanic:
+
+```python
+app = Sanic(load_env='MYAPP_')
+```
+
+Then the above variable would be `MYAPP_REQUEST_TIMEOUT`. If you want to disable loading from environment variables you can set it to `False` instead:
 
 ```python
 app = Sanic(load_env=False)

sanic/config.py

@@ -131,7 +131,8 @@ def __init__(self, defaults=None, load_env=True, keep_alive=True):
         self.GRACEFUL_SHUTDOWN_TIMEOUT = 15.0  # 15 sec
 
         if load_env:
-            self.load_environment_vars()
+            prefix = SANIC_PREFIX if load_env is True else load_env
+            self.load_environment_vars(prefix=prefix)
 
     def __getattr__(self, attr):
         try:
@@ -195,14 +196,14 @@ def from_object(self, obj):
             if key.isupper():
                 self[key] = getattr(obj, key)
 
-    def load_environment_vars(self):
+    def load_environment_vars(self, prefix=SANIC_PREFIX):
         """
-        Looks for any ``SANIC_`` prefixed environment variables and applies
+        Looks for prefixed environment variables and applies
         them to the configuration if present.
         """
         for k, v in os.environ.items():
-            if k.startswith(SANIC_PREFIX):
-                _, config_key = k.split(SANIC_PREFIX, 1)
+            if k.startswith(prefix):
+                _, config_key = k.split(prefix, 1)
                 try:
                     self[config_key] = int(v)
                 except ValueError:

tests/test_config.py

@@ -19,15 +19,21 @@ class Config:
 def test_auto_load_env():
     environ["SANIC_TEST_ANSWER"] = "42"
     app = Sanic()
-    assert app.config.TEST_ANSWER == "42"
+    assert app.config.TEST_ANSWER == 42
     del environ["SANIC_TEST_ANSWER"]
 
-def test_auto_load_env():
+def test_dont_load_env():
     environ["SANIC_TEST_ANSWER"] = "42"
     app = Sanic(load_env=False)
     assert getattr(app.config, 'TEST_ANSWER', None) == None
     del environ["SANIC_TEST_ANSWER"]
 
+def test_load_env_prefix():
+    environ["MYAPP_TEST_ANSWER"] = "42"
+    app = Sanic(load_env='MYAPP_')
+    assert app.config.TEST_ANSWER == 42
+    del environ["MYAPP_TEST_ANSWER"]
+
 def test_load_from_file():
     app = Sanic('test_load_from_file')
     config = b"""