#4: Gather CharmStore endpoint and timeout from environment

This change allows a user to set the environment variables CS_API_URL and
CS_API_TIMEOUT to repectively set the Charm Store endpoint URL and how
long to wait before a Charm Store query times out.

This could also be a step towards removing the DEFAULT_CS_API_URL from
libcharmstore.

* Increment version

README.md

@@ -1,5 +1,14 @@
 # CharmStore Python Library
 
+The environment variables CS\_API\_URL and CS\_API\_TIMEOUT can be set to
+repectively set the Charm Store endpoint URL and how long to wait before a
+Charm Store query times out.
+
+```bash
+export CS_API_URL=https://api.jujucharms.com/v4
+export CS_API_TIMEOUT=200
+```
+
 ```python
 from charmstore import CharmStore, Charm, Bundle
 ```

charmstore/lib.py

@@ -1,3 +1,4 @@
+import os
 import re
 import json
 
@@ -30,8 +31,10 @@
 
 
 class CharmStore(object):
-    def __init__(self, api=DEFAULT_CS_API_URL):
+    def __init__(self, api=None):
         super(CharmStore, self).__init__()
+        if not api:
+            api = os.environ.get('CS_API_URL', DEFAULT_CS_API_URL)
         self.theblues = charmstore.CharmStore(url=api)
 
     def requires(self, interfaces=[], limit=None):
@@ -82,8 +85,11 @@ def from_data(cls, data):
 
         return e
 
-    def __init__(self, id=None, api=DEFAULT_CS_API_URL,
-                 timeout=DEFAULT_TIMEOUT):
+    def __init__(self, id=None, api=None, timeout=None):
+        if not api:
+            api = os.environ.get('CS_API_URL', DEFAULT_CS_API_URL)
+        if not timeout:
+            timeout = float(os.environ.get('CS_API_TIMEOUT', DEFAULT_TIMEOUT))
         self.id = None
         self.name = None
         self.owner = None
@@ -141,8 +147,7 @@ def load(self, data):
 
 
 class Charm(Entity):
-    def __init__(self, id=None, api=DEFAULT_CS_API_URL,
-                 timeout=DEFAULT_TIMEOUT):
+    def __init__(self, id=None, api=None, timeout=None):
         self.summary = None
         self.description = None
 
@@ -210,7 +215,7 @@ def __repr__(self):
 
 
 class Bundle(Entity):
-    def __init__(self, id=None, timeout=DEFAULT_TIMEOUT):
+    def __init__(self, id=None, timeout=None):
         self.count = {'machines': 0, 'units': 0}
         self.relations = []
         self.services = None

setup.py

@@ -8,7 +8,7 @@
 
 setup(
     name='libcharmstore',
-    version='0.0.5',
+    version='0.0.6',
     packages=['charmstore'],
     maintainer='Marco Ceppi',
     install_requires=[

tests/test_entity.py

@@ -4,7 +4,7 @@
 
 from mock import patch
 
-from charmstore.lib import Entity
+import charmstore.lib
 from util import CHARM, BUNDLE
 
 
@@ -14,7 +14,7 @@ def setUpClass(cls):
         pass
 
     def test_entity_load(self):
-        c = Entity.from_data(CHARM.get('Meta'))
+        c = charmstore.lib.Entity.from_data(CHARM.get('Meta'))
         self.assertEqual(c.id, 'trusty/benchmark-gui-0')
         self.assertEqual(c.url, 'cs:trusty/benchmark-gui-0')
         self.assertEqual(c.series, 'trusty')
@@ -31,3 +31,20 @@ def test_entity_load(self):
         self.assertEqual(c.stats, {})
 
         self.assertEqual(c.raw, CHARM.get('Meta'))
+
+    @patch.object(charmstore.lib, 'charmstore')
+    def test_entity_default_cs_params(self, _charmstore):
+        charmstore.lib.Entity.from_data(CHARM.get('Meta'))
+        _charmstore.CharmStore.assert_called_once_with(
+            timeout=10.0,
+            url='https://api.jujucharms.com/v4')
+
+    @patch.dict(charmstore.lib.os.environ, {
+        'CS_API_URL': 'alturl',
+        'CS_API_TIMEOUT': '200'})
+    @patch.object(charmstore.lib, 'charmstore')
+    def test_entity_env(self, _charmstore):
+        charmstore.lib.Entity.from_data(CHARM.get('Meta'))
+        _charmstore.CharmStore.assert_called_once_with(
+            timeout=200.0,
+            url='alturl')