[Feature] implement log channel separation and request log level system (#7190)

* feat: implement log channel separation and request log level system

* fix: log system improvements based on review

* add request_id to error logs, use RequestLogLevel enum, and unify logger implementation from utils to logger module

tests/logger/test_request_logger.py

@@ -0,0 +1,176 @@
+# Copyright (c) 2025 PaddlePaddle Authors. All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import unittest
+from unittest.mock import patch
+
+from fastdeploy.logger.request_logger import (
+    RequestLogLevel,
+    _should_log,
+    _truncate,
+    log_request,
+    log_request_error,
+)
+
+
+class TestRequestLogLevel(unittest.TestCase):
+    """Test RequestLogLevel enum"""
+
+    def test_level_values(self):
+        """Test level values"""
+        self.assertEqual(int(RequestLogLevel.LIFECYCLE), 0)
+        self.assertEqual(int(RequestLogLevel.STAGES), 1)
+        self.assertEqual(int(RequestLogLevel.CONTENT), 2)
+        self.assertEqual(int(RequestLogLevel.FULL), 3)
+
+
+class TestShouldLog(unittest.TestCase):
+    """Test _should_log function"""
+
+    def test_disabled_returns_false(self):
+        """FD_LOG_REQUESTS=0 should return False"""
+        with patch("fastdeploy.logger.request_logger.envs") as mock_envs:
+            mock_envs.FD_LOG_REQUESTS = 0
+            mock_envs.FD_LOG_REQUESTS_LEVEL = 3
+            self.assertFalse(_should_log(RequestLogLevel.LIFECYCLE))
+
+    def test_level_within_threshold(self):
+        """Level within threshold should return True"""
+        with patch("fastdeploy.logger.request_logger.envs") as mock_envs:
+            mock_envs.FD_LOG_REQUESTS = 1
+            mock_envs.FD_LOG_REQUESTS_LEVEL = 2
+            self.assertTrue(_should_log(RequestLogLevel.LIFECYCLE))
+            self.assertTrue(_should_log(RequestLogLevel.STAGES))
+            self.assertTrue(_should_log(RequestLogLevel.CONTENT))
+
+    def test_level_above_threshold(self):
+        """Level above threshold should return False"""
+        with patch("fastdeploy.logger.request_logger.envs") as mock_envs:
+            mock_envs.FD_LOG_REQUESTS = 1
+            mock_envs.FD_LOG_REQUESTS_LEVEL = 1
+            self.assertFalse(_should_log(RequestLogLevel.CONTENT))
+            self.assertFalse(_should_log(RequestLogLevel.FULL))
+
+
+class TestTruncate(unittest.TestCase):
+    """Test _truncate function"""
+
+    def test_short_text_unchanged(self):
+        """Short text should remain unchanged"""
+        with patch("fastdeploy.logger.request_logger.envs") as mock_envs:
+            mock_envs.FD_LOG_MAX_LEN = 100
+            result = _truncate("short text")
+            self.assertEqual(result, "short text")
+
+    def test_long_text_truncated(self):
+        """Long text should be truncated"""
+        with patch("fastdeploy.logger.request_logger.envs") as mock_envs:
+            mock_envs.FD_LOG_MAX_LEN = 10
+            result = _truncate("this is a very long text")
+            self.assertEqual(result, "this is a ")
+            self.assertEqual(len(result), 10)
+
+    def test_non_string_converted(self):
+        """Non-string should be converted"""
+        with patch("fastdeploy.logger.request_logger.envs") as mock_envs:
+            mock_envs.FD_LOG_MAX_LEN = 100
+            result = _truncate(12345)
+            self.assertEqual(result, "12345")
+
+
+class TestLogRequest(unittest.TestCase):
+    """Test log_request function"""
+
+    @patch("fastdeploy.logger._request_logger")
+    def test_log_when_enabled(self, mock_logger):
+        """Should log when enabled"""
+        with patch("fastdeploy.logger.request_logger.envs") as mock_envs:
+            mock_envs.FD_LOG_REQUESTS = 1
+            mock_envs.FD_LOG_REQUESTS_LEVEL = 0
+            mock_envs.FD_LOG_MAX_LEN = 2048
+
+            log_request(RequestLogLevel.LIFECYCLE, message="test {value}", value="hello")
+            mock_logger.info.assert_called_once()
+            call_args = mock_logger.info.call_args[0][0]
+            self.assertEqual(call_args, "test hello")
+
+    @patch("fastdeploy.logger._request_logger")
+    def test_no_log_when_disabled(self, mock_logger):
+        """Should not log when disabled"""
+        with patch("fastdeploy.logger.request_logger.envs") as mock_envs:
+            mock_envs.FD_LOG_REQUESTS = 0
+            mock_envs.FD_LOG_REQUESTS_LEVEL = 3
+
+            log_request(RequestLogLevel.LIFECYCLE, message="test {value}", value="hello")
+            mock_logger.info.assert_not_called()
+
+    @patch("fastdeploy.logger._request_logger")
+    def test_no_log_when_level_too_high(self, mock_logger):
+        """Should not log when level is too high"""
+        with patch("fastdeploy.logger.request_logger.envs") as mock_envs:
+            mock_envs.FD_LOG_REQUESTS = 1
+            mock_envs.FD_LOG_REQUESTS_LEVEL = 0
+
+            log_request(RequestLogLevel.CONTENT, message="test {value}", value="hello")
+            mock_logger.info.assert_not_called()
+
+    @patch("fastdeploy.logger._request_logger")
+    def test_content_level_truncates_content(self, mock_logger):
+        """CONTENT level should truncate content"""
+        with patch("fastdeploy.logger.request_logger.envs") as mock_envs:
+            mock_envs.FD_LOG_REQUESTS = 1
+            mock_envs.FD_LOG_REQUESTS_LEVEL = 3
+            mock_envs.FD_LOG_MAX_LEN = 5
+
+            log_request(RequestLogLevel.CONTENT, message="content: {data}", data="very long data")
+            mock_logger.info.assert_called_once()
+            call_args = mock_logger.info.call_args[0][0]
+            self.assertEqual(call_args, "content: very ")
+
+    @patch("fastdeploy.logger._request_logger")
+    def test_lifecycle_level_no_truncation(self, mock_logger):
+        """LIFECYCLE level should not truncate content"""
+        with patch("fastdeploy.logger.request_logger.envs") as mock_envs:
+            mock_envs.FD_LOG_REQUESTS = 1
+            mock_envs.FD_LOG_REQUESTS_LEVEL = 3
+            mock_envs.FD_LOG_MAX_LEN = 5
+
+            log_request(RequestLogLevel.LIFECYCLE, message="content: {data}", data="very long data")
+            mock_logger.info.assert_called_once()
+            call_args = mock_logger.info.call_args[0][0]
+            self.assertEqual(call_args, "content: very long data")
+
+
+class TestLogRequestError(unittest.TestCase):
+    """Test log_request_error function"""
+
+    @patch("fastdeploy.logger._request_logger")
+    def test_error_with_fields(self, mock_logger):
+        """Error log with fields should format message"""
+        log_request_error(message="request {request_id} failed: {error}", request_id="req-123", error="timeout")
+        mock_logger.error.assert_called_once()
+        call_args = mock_logger.error.call_args[0][0]
+        self.assertEqual(call_args, "request req-123 failed: timeout")
+
+    @patch("fastdeploy.logger._request_logger")
+    def test_error_without_fields(self, mock_logger):
+        """Error log without fields should not call format"""
+        log_request_error(message="simple error message")
+        mock_logger.error.assert_called_once()
+        call_args = mock_logger.error.call_args[0][0]
+        self.assertEqual(call_args, "simple error message")
+
+
+if __name__ == "__main__":
+    unittest.main()