Make scales, blist optional dependencies

Fixes #114

CHANGELOG.rst

@@ -19,6 +19,7 @@ Other
 -----
 * Don't log at ERROR when a connection is closed during the startup
   communications
+* Mke scales, blist optional dependencies
 
 1.1.1
 =====

cassandra/metrics.py

@@ -15,7 +15,12 @@
 from itertools import chain
 import logging
 
-from greplin import scales
+try:
+    from greplin import scales
+except ImportError:
+    raise ImportError(
+        "The scales library is required for metrics support: "
+        "https://pypi.python.org/pypi/scales")
 
 log = logging.getLogger(__name__)
 

requirements.txt

@@ -1,3 +1 @@
-blist
 futures
-scales

setup.py

@@ -31,7 +31,6 @@ from distutils.errors import (CCompilerError, DistutilsPlatformError,
 from distutils.cmd import Command
 
 
-import platform
 import os
 import warnings
 
@@ -181,9 +180,7 @@ def run_setup(extensions):
         kw['cmdclass']['build_ext'] = build_extensions
         kw['ext_modules'] = extensions
 
-    dependencies = ['futures', 'scales', 'blist']
-    if platform.python_implementation() != "CPython":
-        dependencies.remove('blist')
+    dependencies = ['futures']
 
     setup(
         name='cassandra-driver',

test-requirements.txt

@@ -1,3 +1,4 @@
+scales
 nose
 mock
 ccm

tox.ini

@@ -8,5 +8,6 @@ deps = nose
        unittest2
        pip
        PyYAML
+       scales
 commands = {envpython} setup.py build_ext --inplace
            nosetests --verbosity=2 tests/unit/