Fix check-default-configuration check and harden the error case

Root cause: providers_discovery.py used structlog.getLogger() directly. Before structlog.configure() is called (which happens later in settings.py:726), structlog's default PrintLogger writes to stdout with no level filtering. So debug logs during early provider
  discovery pollute the stdout of airflow config list --default, corrupting the generated config file.

Fix: Switched to logging.getLogger() (stdlib). stdlib logging defaults to WARNING level and writes to stderr, so debug logs are suppressed and stdout stays clean. This is also the correct pattern for shared library code — structlog configuration is the application's
  responsibility.

Author: jason810496

scripts/in_container/run_check_default_configuration.py

@@ -36,23 +36,37 @@
 
 if __name__ == "__main__":
     with tempfile.TemporaryDirectory() as tmp_dir:
+        # We need to explicitly set the logging level to ERROR to avoid debug logs from "airflow config lint" command that can spoil the output and make the test fail.
+        # This is needed in case the default config has logging level set to DEBUG, but it does not hurt to set it explicitly in any case to avoid any unexpected debug logs from the command.
+        env = os.environ.copy()
+        env["AIRFLOW__LOGGING__LOGGING_LEVEL"] = "ERROR"
+
         # Write default config cmd output to a temporary file
         default_config_file = os.path.join(tmp_dir, "airflow.cfg")
         with open(default_config_file, "w") as f:
-            result = subprocess.run(list_default_config_cmd, check=False, stdout=f)
+            result = subprocess.run(list_default_config_cmd, check=False, stdout=f, env=env)
         if result.returncode != 0:
             print(f"\033[0;31mERROR: when running `{' '.join(list_default_config_cmd)}`\033[0m\n")
+            print(result.stdout.decode())
             exit(1)
         # Run airflow config lint to check the default config
-        env = os.environ.copy()
         env["AIRFLOW_HOME"] = tmp_dir
         env["AIRFLOW_CONFIG"] = default_config_file
         result = subprocess.run(lint_config_cmd, check=False, capture_output=True, env=env)
 
-    output: str = result.stdout.decode().strip()
-    if result.returncode != 0 or expected_output not in output:
-        print(f"\033[0;31mERROR: when running `{' '.join(lint_config_cmd)}`\033[0m\n")
-        print(output)
-        exit(1)
-    print(output)
-    exit(0)
+        output: str = result.stdout.decode().strip()
+        if result.returncode != 0 or expected_output not in output:
+            print(f"\033[0;31mERROR: when running `{' '.join(lint_config_cmd)}`\033[0m\n")
+            print(output)
+            # log the stderr as well if available
+            if result.stderr:
+                print(f"\033[0;31mERROR: stderr from `{' '.join(lint_config_cmd)}`\033[0m\n")
+                print(result.stderr.decode())
+            # log the default config that was generated for debugging
+            print("\033[0;31mGenerated default config for debugging:\033[0m\n")
+            with open(default_config_file) as f:
+                print(f.read())
+            exit(1)
+        else:
+            print(output)
+            exit(0)

shared/providers_discovery/src/airflow_shared/providers_discovery/providers_discovery.py

@@ -21,6 +21,7 @@
 
 import contextlib
 import json
+import logging
 import pathlib
 from collections.abc import Callable, MutableMapping
 from dataclasses import dataclass
@@ -29,12 +30,11 @@
 from time import perf_counter
 from typing import Any, NamedTuple, ParamSpec, Protocol, cast
 
-import structlog
 from packaging.utils import canonicalize_name
 
 from ..module_loading import entry_points_with_dist
 
-log = structlog.getLogger(__name__)
+log = logging.getLogger(__name__)
 
 
 PS = ParamSpec("PS")