[PFS] Start pfs in foreground and log in terminal and file in debug mode

src/promptflow-devkit/promptflow/_cli/_pf/_service.py

@@ -157,42 +157,35 @@ def start_service(args):
     port = args.port
     if args.debug:
         os.environ[PF_SERVICE_DEBUG] = "true"
-
-    if is_run_from_built_binary():
-        # For msi installer/executable, use sdk api to start pfs since it's not supported to invoke waitress by cli
-        # directly after packaged by Pyinstaller.
-        parent_dir = os.path.dirname(sys.executable)
-        output_path = os.path.join(parent_dir, "output.txt")
-        with redirect_stdout_to_file(output_path):
-            port = validate_port(port, args.force)
-            global app
-            if app is None:
-                app, _ = create_app()
-            if os.environ.get(PF_SERVICE_DEBUG) == "true":
-                app.logger.setLevel(logging.DEBUG)
-            else:
-                app.logger.setLevel(logging.INFO)
-            message = f"Starting Prompt Flow Service on {port}, version: {get_pfs_version()}."
-            app.logger.info(message)
-            print(message)
-            sys.stdout.flush()
+        if not is_run_from_built_binary():
+            add_executable_script_to_env_path()
+        port = _prepare_app_for_foreground_service(port, args.force)
         waitress.serve(app, host="127.0.0.1", port=port, threads=PF_SERVICE_WORKER_NUM)
     else:
-        port = validate_port(port, args.force)
-        add_executable_script_to_env_path()
-        # Start a pfs process using detach mode. It will start a new process and create a new app. So we use environment
-        # variable to pass the debug mode, since it will inherit parent process environment variable.
-        if platform.system() == "Windows":
-            _start_background_service_on_windows(port)
-        else:
-            _start_background_service_on_unix(port)
-        is_healthy = check_pfs_service_status(port)
-        if is_healthy:
-            message = f"Start Promptflow Service on port {port}, version: {get_pfs_version()}."
-            print(message)
-            logger.info(message)
+        if is_run_from_built_binary():
+            # For msi installer/executable, use sdk api to start pfs since it's not supported to invoke waitress by cli
+            # directly after packaged by Pyinstaller.
+            parent_dir = os.path.dirname(sys.executable)
+            output_path = os.path.join(parent_dir, "output.txt")
+            with redirect_stdout_to_file(output_path):
+                port = _prepare_app_for_foreground_service(port, args.force)
+            waitress.serve(app, host="127.0.0.1", port=port, threads=PF_SERVICE_WORKER_NUM)
         else:
-            logger.warning(f"Promptflow service start failed in {port}. {hint_stop_before_upgrade}")
+            port = validate_port(port, args.force)
+            add_executable_script_to_env_path()
+            # Start a pfs process using detach mode. It will start a new process and create a new app. So we use
+            # environment variable to pass the debug mode, since it will inherit parent process environment variable.
+            if platform.system() == "Windows":
+                _start_background_service_on_windows(port)
+            else:
+                _start_background_service_on_unix(port)
+            is_healthy = check_pfs_service_status(port)
+            if is_healthy:
+                message = f"Start Promptflow Service on port {port}, version: {get_pfs_version()}."
+                print(message)
+                logger.info(message)
+            else:
+                logger.warning(f"Promptflow service start failed in {port}. {hint_stop_before_upgrade}")
 
 
 def validate_port(port, force_start):
@@ -238,6 +231,21 @@ def redirect_stdout_to_file(path):
         sys.stderr = old_stderr
 
 
+def _prepare_app_for_foreground_service(port, force_start):
+    port = validate_port(port, force_start)
+    global app
+    if app is None:
+        app, _ = create_app()
+    if os.environ.get(PF_SERVICE_DEBUG) == "true":
+        app.logger.setLevel(logging.DEBUG)
+    else:
+        app.logger.setLevel(logging.INFO)
+    message = f"Starting Prompt Flow Service on {port}, version: {get_pfs_version()}."
+    app.logger.info(message)
+    print(message)
+    return port
+
+
 def _start_background_service_on_windows(port):
     try:
         import win32api

src/promptflow-devkit/promptflow/_sdk/_service/app.py

@@ -2,6 +2,7 @@
 # Copyright (c) Microsoft Corporation. All rights reserved.
 # ---------------------------------------------------------
 import logging
+import os
 import threading
 import time
 from datetime import datetime, timedelta
@@ -14,6 +15,7 @@
 
 from promptflow._sdk._constants import (
     HOME_PROMPT_FLOW_DIR,
+    PF_SERVICE_DEBUG,
     PF_SERVICE_HOUR_TIMEOUT,
     PF_SERVICE_LOG_FILE,
     PF_SERVICE_MONITOR_SECOND,
@@ -98,8 +100,19 @@ def create_app():
         handler = RotatingFileHandler(filename=log_file, maxBytes=1_000_000, backupCount=1)
         formatter = logging.Formatter("[%(asctime)s][%(name)s][%(levelname)s] - %(message)s")
         handler.setFormatter(formatter)
+
+        # Create a stream handler to output logs to the terminal
+        stream_handler = logging.StreamHandler()
+        stream_handler.setFormatter(formatter)
+
         # Set app logger to the only one RotatingFileHandler to avoid duplicate logs
         app.logger.handlers = [handler]
+        if os.environ.get(PF_SERVICE_DEBUG) == "true":
+            # Set app logger to use both the rotating file handler and the stream handler in debug mode
+            app.logger.handlers.append(stream_handler)
+
+        # Prevent logs from being handled by the root logger
+        app.logger.propagate = False
 
         # Basic error handler
         @api.errorhandler(Exception)