app.run is not lazy

use click.echo for banner messages

flask/app.py

@@ -933,7 +933,7 @@ class Flask(_PackageBoundObject):
         options.setdefault('use_debugger', self.debug)
         options.setdefault('threaded', True)
 
-        cli.show_server_banner(self.env, self.debug, self.name)
+        cli.show_server_banner(self.env, self.debug, self.name, False)
 
         from werkzeug.serving import run_simple
 

flask/cli.py

@@ -614,7 +614,7 @@ def load_dotenv(path=None):
     return new_dir is not None  # at least one file was located and loaded
 
 
-def show_server_banner(env, debug, app_import_path, eager_loading=True):
+def show_server_banner(env, debug, app_import_path, eager_loading):
     """Show extra startup messages the first time the server is run,
     ignoring the reloader.
     """
@@ -623,11 +623,13 @@ def show_server_banner(env, debug, app_import_path, eager_loading=True):
 
     if app_import_path is not None:
         message = ' * Serving Flask app "{0}"'.format(app_import_path)
+
         if not eager_loading:
             message += ' (lazy loading)'
-        print(message)
 
-    print(' * Environment: {0}'.format(env))
+        click.echo(message)
+
+    click.echo(' * Environment: {0}'.format(env))
 
     if env == 'production':
         click.secho(
@@ -636,7 +638,7 @@ def show_server_banner(env, debug, app_import_path, eager_loading=True):
         click.secho('   Use a production WSGI server instead.', dim=True)
 
     if debug is not None:
-        print(' * Debug mode: {0}'.format('on' if debug else 'off'))
+        click.echo(' * Debug mode: {0}'.format('on' if debug else 'off'))
 
 
 class CertParamType(click.ParamType):