Move DD code into its own directory (#6)

reference/ddtrace/utils/formats.py

@@ -0,0 +1,82 @@
+import os
+
+from .deprecation import deprecation
+
+
+def get_env(integration, variable, default=None):
+    """Retrieves environment variables value for the given integration. It must be used
+    for consistency between integrations. The implementation is backward compatible
+    with legacy nomenclature:
+
+    * `DATADOG_` is a legacy prefix with lower priority
+    * `DD_` environment variables have the highest priority
+    * the environment variable is built concatenating `integration` and `variable`
+      arguments
+    * return `default` otherwise
+
+    """
+    key = "{}_{}".format(integration, variable).upper()
+    legacy_env = "DATADOG_{}".format(key)
+    env = "DD_{}".format(key)
+
+    value = os.getenv(env)
+    legacy = os.getenv(legacy_env)
+    if legacy:
+        # Deprecation: `DATADOG_` variables are deprecated
+        deprecation(
+            name="DATADOG_", message="Use `DD_` prefix instead", version="1.0.0",
+        )
+
+    value = value or legacy
+    return value if value else default
+
+
+def deep_getattr(obj, attr_string, default=None):
+    """
+    Returns the attribute of `obj` at the dotted path given by `attr_string`
+    If no such attribute is reachable, returns `default`
+
+    >>> deep_getattr(cass, 'cluster')
+    <cassandra.cluster.Cluster object at 0xa20c350
+
+    >>> deep_getattr(cass, 'cluster.metadata.partitioner')
+    u'org.apache.cassandra.dht.Murmur3Partitioner'
+
+    >>> deep_getattr(cass, 'i.dont.exist', default='default')
+    'default'
+    """
+    attrs = attr_string.split(".")
+    for attr in attrs:
+        try:
+            obj = getattr(obj, attr)
+        except AttributeError:
+            return default
+
+    return obj
+
+
+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 flatten_dict(d, sep=".", prefix=""):
+    """
+    Returns a normalized dict of depth 1 with keys in order of embedding
+
+    """
+    # adapted from https://stackoverflow.com/a/19647596
+    return (
+        {prefix + sep + k if prefix else k: v for kk, vv in d.items() for k, v in flatten_dict(vv, sep, kk).items()}
+        if isinstance(d, dict)
+        else {prefix: d}
+    )