Move DD code into its own directory (#6)

reference/ddtrace/compat.py

@@ -0,0 +1,151 @@
+import platform
+import re
+import sys
+import textwrap
+
+from ddtrace.vendor import six
+
+__all__ = [
+    'httplib',
+    'iteritems',
+    'PY2',
+    'Queue',
+    'stringify',
+    'StringIO',
+    'urlencode',
+    'parse',
+    'reraise',
+]
+
+PYTHON_VERSION_INFO = sys.version_info
+PY2 = sys.version_info[0] == 2
+PY3 = sys.version_info[0] == 3
+
+# Infos about python passed to the trace agent through the header
+PYTHON_VERSION = platform.python_version()
+PYTHON_INTERPRETER = platform.python_implementation()
+
+try:
+    StringIO = six.moves.cStringIO
+except ImportError:
+    StringIO = six.StringIO
+
+httplib = six.moves.http_client
+urlencode = six.moves.urllib.parse.urlencode
+parse = six.moves.urllib.parse
+Queue = six.moves.queue.Queue
+iteritems = six.iteritems
+reraise = six.reraise
+reload_module = six.moves.reload_module
+
+stringify = six.text_type
+string_type = six.string_types[0]
+msgpack_type = six.binary_type
+# DEV: `six` doesn't have `float` in `integer_types`
+numeric_types = six.integer_types + (float, )
+
+# Pattern class generated by `re.compile`
+if PYTHON_VERSION_INFO >= (3, 7):
+    pattern_type = re.Pattern
+else:
+    pattern_type = re._pattern_type
+
+
+def is_integer(obj):
+    """Helper to determine if the provided ``obj`` is an integer type or not"""
+    # DEV: We have to make sure it is an integer and not a boolean
+    # >>> type(True)
+    # <class 'bool'>
+    # >>> isinstance(True, int)
+    # True
+    return isinstance(obj, six.integer_types) and not isinstance(obj, bool)
+
+
+try:
+    from time import time_ns
+except ImportError:
+    from time import time as _time
+
+    def time_ns():
+        return int(_time() * 10e5) * 1000
+
+
+if PYTHON_VERSION_INFO[0:2] >= (3, 4):
+    from asyncio import iscoroutinefunction
+
+    # Execute from a string to get around syntax errors from `yield from`
+    # DEV: The idea to do this was stolen from `six`
+    #   https://github.com/benjaminp/six/blob/15e31431af97e5e64b80af0a3f598d382bcdd49a/six.py#L719-L737
+    six.exec_(textwrap.dedent("""
+    import functools
+    import asyncio
+
+
+    def make_async_decorator(tracer, coro, *params, **kw_params):
+        \"\"\"
+        Decorator factory that creates an asynchronous wrapper that yields
+        a coroutine result. This factory is required to handle Python 2
+        compatibilities.
+
+        :param object tracer: the tracer instance that is used
+        :param function f: the coroutine that must be executed
+        :param tuple params: arguments given to the Tracer.trace()
+        :param dict kw_params: keyword arguments given to the Tracer.trace()
+        \"\"\"
+        @functools.wraps(coro)
+        @asyncio.coroutine
+        def func_wrapper(*args, **kwargs):
+            with tracer.trace(*params, **kw_params):
+                result = yield from coro(*args, **kwargs)  # noqa: E999
+                return result
+
+        return func_wrapper
+    """))
+
+else:
+    # asyncio is missing so we can't have coroutines; these
+    # functions are used only to ensure code executions in case
+    # of an unexpected behavior
+    def iscoroutinefunction(fn):
+        return False
+
+    def make_async_decorator(tracer, fn, *params, **kw_params):
+        return fn
+
+
+# DEV: There is `six.u()` which does something similar, but doesn't have the guard around `hasattr(s, 'decode')`
+def to_unicode(s):
+    """ Return a unicode string for the given bytes or string instance. """
+    # No reason to decode if we already have the unicode compatible object we expect
+    # DEV: `six.text_type` will be a `str` for python 3 and `unicode` for python 2
+    # DEV: Double decoding a `unicode` can cause a `UnicodeEncodeError`
+    #   e.g. `'\xc3\xbf'.decode('utf-8').decode('utf-8')`
+    if isinstance(s, six.text_type):
+        return s
+
+    # If the object has a `decode` method, then decode into `utf-8`
+    #   e.g. Python 2 `str`, Python 2/3 `bytearray`, etc
+    if hasattr(s, 'decode'):
+        return s.decode('utf-8')
+
+    # Always try to coerce the object into the `six.text_type` object we expect
+    #   e.g. `to_unicode(1)`, `to_unicode(dict(key='value'))`
+    return six.text_type(s)
+
+
+def get_connection_response(conn):
+    """Returns the response for a connection.
+
+    If using Python 2 enable buffering.
+
+    Python 2 does not enable buffering by default resulting in many recv
+    syscalls.
+
+    See:
+    https://bugs.python.org/issue4879
+    https://github.com/python/cpython/commit/3c43fcba8b67ea0cec4a443c755ce5f25990a6cf
+    """
+    if PY2:
+        return conn.getresponse(buffering=True)
+    else:
+        return conn.getresponse()