disallow configuring dd_trace_api patching via envvars

Author: emmettbutler

ddtrace/_monkey.py

@@ -158,6 +158,8 @@
     ),
 }
 
+_NOT_PATCHABLE_VIA_ENVVAR = {"dd_trace_api"}
+
 
 class PatchException(Exception):
     """Wraps regular `Exception` class when patching modules"""
@@ -212,8 +214,7 @@ def on_import(hook):
     return on_import
 
 
-def patch_all(**patch_modules):
-    # type: (bool) -> None
+def patch_all(**patch_modules: bool) -> None:
     """Enables ddtrace library instrumentation.
 
     In addition to ``patch_modules``, an override can be specified via an
@@ -230,7 +231,7 @@ def patch_all(**patch_modules):
     # The enabled setting can be overridden by environment variables
     for module, _enabled in modules.items():
         env_var = "DD_TRACE_%s_ENABLED" % module.upper()
-        if env_var in os.environ:
+        if module not in _NOT_PATCHABLE_VIA_ENVVAR and env_var in os.environ:
             modules[module] = formats.asbool(os.environ[env_var])
 
         # Enable all dependencies for the module