fix(formatter): custom fields

pyproject.toml

@@ -1,6 +1,6 @@
 [project]
 name = "bunyan-formatter"
-version = "1.0.0"
+version = "0.1.0"
 description = "Bunyan Formatter for Python"
 dependencies = []
 readme = "README.md"

src/bunyan_formatter/logger.py

@@ -2,13 +2,36 @@ import json
 import logging
 import socket
 import time
+import traceback
 from logging import Formatter, LogRecord
 from pathlib import Path
-from typing import ClassVar, Optional
+from typing import Any, Optional
 
+DEFAULT_FIELDS = {
+    "name",
+    "msg",
+    "args",
+    "levelname",
+    "levelno",
+    "pathname",
+    "filename",
+    "module",
+    "exc_info",
+    "exc_text",
+    "stack_info",
+    "lineno",
+    "funcName",
+    "created",
+    "msecs",
+    "relativeCreated",
+    "thread",
+    "threadName",
+    "processName",
+    "process",
+    "taskName",
+}
 
-class BunyanFormatter(Formatter):
+LEVEL_MAP = {
-    LEVEL_MAP: ClassVar[dict[int, int]] = {
     logging.NOTSET: 10,
     logging.DEBUG: 20,
     logging.INFO: 30,
@@ -17,6 +40,8 @@ class BunyanFormatter(Formatter):
     logging.CRITICAL: 60,
 }
 
+
+class BunyanFormatter(Formatter):
     def __init__(self, project_name: str, project_root: Path) -> None:
         super().__init__()
         self.project_name = project_name
@@ -24,8 +49,6 @@ class BunyanFormatter(Formatter):
         self.hostname = socket.gethostname()
 
     def format(self, record: LogRecord) -> str:
-        hostname = socket.gethostname()
-
         file_path = Path(record.pathname)
         try:
             relative_path = file_path.relative_to(self.project_root)
@@ -36,9 +59,9 @@ class BunyanFormatter(Formatter):
             "v": 0,
             "name": self.project_name,
             "msg": record.getMessage(),
-            "level": self.LEVEL_MAP.get(record.levelno, record.levelno),
+            "level": LEVEL_MAP.get(record.levelno, record.levelno),
             "levelname": record.levelname,
-            "hostname": hostname,
+            "hostname": self.hostname,
             "pid": record.process,
             "time": self.formatTime(record),
             "target": record.name,
@@ -46,6 +69,15 @@ class BunyanFormatter(Formatter):
             "file": str(relative_path),
         }
 
+        # Handle extra fields
+        extra_fields = {k: v for k, v in record.__dict__.items() if k not in DEFAULT_FIELDS}
+        if extra_fields:
+            log_entry["extra"] = extra_fields
+
+        # Handle exception information
+        if record.exc_info and all(record.exc_info):
+            log_entry["err"] = self._format_exception(record)
+
         return json.dumps(log_entry)
 
     def formatTime(self, record: LogRecord, datefmt: Optional[str] = None) -> str:  # noqa: N802
@@ -56,3 +88,30 @@ class BunyanFormatter(Formatter):
             t = time.strftime("%Y-%m-%dT%H:%M:%S", ct)
             s = f"{t}.{int(record.msecs):03d}Z"
         return s
+
+    def _format_exception(self, record: LogRecord) -> dict[str, Any]:
+        exc_info = record.exc_info
+
+        if exc_info is None or len(exc_info) != 3:
+            return {}
+
+        exc_type, exc_value, exc_traceback = exc_info
+
+        if exc_type is None or exc_value is None or exc_traceback is None:
+            return {}
+
+        stack = traceback.extract_tb(exc_traceback)
+
+        return {
+            "message": str(exc_value),
+            "name": getattr(exc_type, "__name__", "UnknownException"),
+            "stack": [
+                {
+                    "file": frame.filename,
+                    "line": frame.lineno,
+                    "function": frame.name,
+                    "text": frame.line.strip() if frame.line is not None else "",
+                }
+                for frame in stack
+            ],
+        }

tests/test_formatter.py

@@ -1,6 +1,8 @@
 import json
 import logging
-from logging import LogRecord
+from datetime import datetime
+from io import StringIO
+from logging import LogRecord, StreamHandler
 from pathlib import Path
 from typing import Optional
 from unittest import TestCase
@@ -10,7 +12,11 @@ from bunyan_formatter import BunyanFormatter
 
 
 class TestBunyanFormatter(TestCase):
-    def setUp(self) -> None:
+    @patch("socket.gethostname")
+    def setUp(self, mock_gethostname: Optional[Mock]) -> None:
+        if mock_gethostname is None:
+            raise ValueError("mock_gethostname should not be None")
+        mock_gethostname.return_value = "test_host"
         self.project_name = "test_project"
         self.project_root = Path("/path/to/project")
         self.formatter = BunyanFormatter(self.project_name, self.project_root)
@@ -18,12 +24,7 @@ class TestBunyanFormatter(TestCase):
     def create_log_record(self, level: int, msg: str, pathname: str) -> LogRecord:
         return LogRecord(name="test_logger", level=level, pathname=pathname, lineno=42, msg=msg, args=(), exc_info=None)
 
-    @patch("socket.gethostname")
+    def test_format_basic(self) -> None:
-    def test_format_basic(self, mock_gethostname: Optional[Mock]) -> None:
-        if mock_gethostname is None:
-            raise ValueError("mock_gethostname should not be None")
-
-        mock_gethostname.return_value = "test_host"
         record = self.create_log_record(logging.INFO, "Test message", "/path/to/project/test.py")
 
         formatted = self.formatter.format(record)
@@ -56,11 +57,7 @@ class TestBunyanFormatter(TestCase):
         log_entry = json.loads(formatted)
         assert log_entry["file"] == "/path/outside/project/test.py"
 
-    @patch("socket.gethostname")
+    def test_format_hostname_consistency(self) -> None:
-    def test_format_hostname_consistency(self, mock_gethostname: Optional[Mock]) -> None:
-        if mock_gethostname is None:
-            raise ValueError("mock_gethostname should not be None")
-        mock_gethostname.return_value = "test_host"
         record1 = self.create_log_record(logging.INFO, "Message 1", "/path/to/project/test1.py")
         record2 = self.create_log_record(logging.INFO, "Message 2", "/path/to/project/test2.py")
 
@@ -84,3 +81,126 @@ class TestBunyanFormatter(TestCase):
             datetime.strptime(log_entry["time"], "%Y-%m-%dT%H:%M:%S.%fZ")
         except ValueError:
             self.fail("Time is not in the correct format")
+
+    def test_format_exception(self) -> None:
+        logger = logging.getLogger("test_logger")
+        logger.setLevel(logging.DEBUG)
+
+        stream = StringIO()
+        handler = StreamHandler(stream)
+        handler.setFormatter(self.formatter)
+        logger.addHandler(handler)
+
+        try:
+            raise ValueError("Test error")
+        except ValueError:
+            logger.exception("An error occurred")
+
+        # Get the last logged message
+        last_message = handler.stream.getvalue().splitlines()[-1]
+        log_entry = json.loads(last_message)
+
+        assert log_entry["v"] == 0
+        assert log_entry["name"] == self.project_name
+        assert log_entry["msg"] == "An error occurred"
+        assert log_entry["level"] == 50
+        assert log_entry["levelname"] == "ERROR"
+        assert log_entry["hostname"] == "test_host"
+        assert log_entry["target"] == "test_logger"
+        assert "err" in log_entry
+        assert "message" in log_entry["err"]
+        assert "name" in log_entry["err"]
+        assert "stack" in log_entry["err"]
+
+    def test_format_custom_fields(self) -> None:
+        logger = logging.getLogger("test_logger")
+        logger.setLevel(logging.DEBUG)
+
+        stream = StringIO()
+        handler = StreamHandler(stream)
+        handler.setFormatter(self.formatter)
+        logger.addHandler(handler)
+
+        logger.info("User logged in", extra={"username": "john_doe", "ip_address": "192.168.1.100"})
+
+        # Get the last logged message
+        last_message = handler.stream.getvalue().splitlines()[-1]
+        log_entry = json.loads(last_message)
+
+        assert log_entry["v"] == 0
+        assert log_entry["name"] == self.project_name
+        assert log_entry["msg"] == "User logged in"
+        assert log_entry["level"] == 30
+        assert log_entry["levelname"] == "INFO"
+        assert log_entry["target"] == "test_logger"
+        assert "extra" in log_entry
+        assert log_entry["extra"]["username"] == "john_doe"
+        assert log_entry["extra"]["ip_address"] == "192.168.1.100"
+
+    def test_format_nested_custom_fields(self) -> None:
+        logger = logging.getLogger("test_logger")
+        logger.setLevel(logging.DEBUG)
+
+        stream = StringIO()
+        handler = StreamHandler(stream)
+        handler.setFormatter(self.formatter)
+        logger.addHandler(handler)
+
+        nested_data = {
+            "user": {"id": 123, "email": "user@example.com"},
+            "action": "login",
+            "timestamp": datetime.now().isoformat(),
+        }
+
+        logger.info("Complex action performed", extra={"data": nested_data})
+
+        # Get the last logged message
+        last_message = handler.stream.getvalue().splitlines()[-1]
+        log_entry = json.loads(last_message)
+
+        assert log_entry["v"] == 0
+        assert log_entry["name"] == self.project_name
+        assert log_entry["msg"] == "Complex action performed"
+        assert log_entry["level"] == 30
+        assert log_entry["levelname"] == "INFO"
+        assert log_entry["target"] == "test_logger"
+        assert "extra" in log_entry
+        assert "data" in log_entry["extra"]
+        assert isinstance(log_entry["extra"]["data"], dict)
+        assert log_entry["extra"]["data"]["user"]["id"] == 123
+        assert log_entry["extra"]["data"]["user"]["email"] == "user@example.com"
+        assert log_entry["extra"]["data"]["action"] == "login"
+        assert "timestamp" in log_entry["extra"]["data"]
+
+    def test_format_exception_with_custom_fields(self) -> None:
+        logger = logging.getLogger("test_logger")
+        logger.setLevel(logging.DEBUG)
+
+        stream = StringIO()
+        handler = StreamHandler(stream)
+        handler.setFormatter(self.formatter)
+        logger.addHandler(handler)
+
+        try:
+            raise ValueError("Test error")
+        except ValueError:
+            logger.exception("An error occurred", extra={"error_code": "E001", "user_id": 456})
+
+        # Get the last logged message
+        last_message = handler.stream.getvalue().splitlines()[-1]
+        log_entry = json.loads(last_message)
+
+        assert log_entry["v"] == 0
+        assert log_entry["name"] == self.project_name
+        assert log_entry["msg"] == "An error occurred"
+        assert log_entry["level"] == 50
+        assert log_entry["levelname"] == "ERROR"
+        assert log_entry["hostname"] == "test_host"
+        assert log_entry["target"] == "test_logger"
+        assert "err" in log_entry
+        assert "message" in log_entry["err"]
+        assert "name" in log_entry["err"]
+        assert "stack" in log_entry["err"]
+        assert "extra" in log_entry
+        assert log_entry["extra"]["error_code"] == "E001"
+        assert log_entry["extra"]["user_id"] == 456