add logging, add default skip libs, change the following-span order

datadog_lambda/cold_start.py

@@ -1,6 +1,8 @@
 import time
 import os
 from typing import List, Hashable
+import logging
+logger = logging.getLogger(__name__)
 
 _cold_start = True
 _lambda_container_initialized = False
@@ -103,8 +105,8 @@ def wrapped_find_spec(*args, **kwargs):
  try:
  loader.exec_module = wrap_exec_module(loader.exec_module)
  already_wrapped_loaders.add(loader)
- except Exception:
- pass
+ except Exception as e:
+ logger.debug("Failed to wrap the loader. %s", e)
  return spec
 
  return wrapped_find_spec

datadog_lambda/wrapper.py

@@ -145,9 +145,10 @@ def __init__(self, func):
  self.cold_start_trace_skip_lib = []
  if "DD_COLD_START_TRACE_SKIP_LIB" in os.environ:
  try:
- self.cold_start_trace_skip_lib = os.environ[
- "DD_COLD_START_TRACE_SKIP_LIB"
- ].split(",")
+ self.cold_start_trace_skip_lib = os.environ.get(
+ "DD_COLD_START_TRACE_SKIP_LIB",
+ "datadog_lambda.extension,datadog_lambda.metric,datadog_lambda.patch"
+ ).split(",")
  except Exception:
  logger.debug("Malformatted for env DD_COLD_START_TRACE_SKIP_LIB")
  self.response = None
@@ -302,7 +303,7 @@ def _after(self, event, context):
 
  if should_trace_cold_start:
  try:
- following_span = self.span or self.inferred_span
+ following_span = self.inferred_span or self.span
  ColdStartTracer(
  tracer,
  self.function_name,