[core] add asbool function to parse env vars

Author: Emanuele Palazzetti

ddtrace/util.py

@@ -100,6 +100,18 @@ def _get_original_method(thing, key):
         setattr(patchable, key, dest.__get__(patchable, patchable.__class__))
 
 
+def asbool(value):
+    """Convert the given String to a boolean object. Accepted
+    values are `True` and `1`."""
+    if value is None:
+        return False
+
+    if isinstance(value, bool):
+        return value
+
+    return value.lower() in ("true", "1")
+
+
 def unwrap(obj, attr):
     f = getattr(obj, attr, None)
     if f and isinstance(f, wrapt.ObjectProxy) and hasattr(f, '__wrapped__'):

tests/contrib/test_utils.py

@@ -1,6 +1,7 @@
 from nose.tools import eq_
 
 from ddtrace.contrib.util import func_name
+from ddtrace.util import asbool
 from functools import partial
 
 class SomethingCallable(object):

tests/test_utils.py

@@ -0,0 +1,19 @@
+import unittest
+
+from nose.tools import eq_
+
+from ddtrace.util import asbool
+
+
+class TestUtilities(unittest.TestCase):
+    def test_asbool(self):
+        # ensure the value is properly cast
+        eq_(asbool("True"), True)
+        eq_(asbool("true"), True)
+        eq_(asbool("1"), True)
+        eq_(asbool("False"), False)
+        eq_(asbool("false"), False)
+        eq_(asbool(None), False)
+        eq_(asbool(""), False)
+        eq_(asbool(True), True)
+        eq_(asbool(False), False)