🔧 Open up logging (#237)

* 🔧 Open up logging

Create methods on logger for add/remove handlers and get all handlers. Expose these in global methods as well on the global instance of LOG.

Open up the get methods for file and stream handlers

Remove the file logger since it now can be added afterward instead of by default.

* ✅ MyPy correction to silent

'silent' apparently should be without quotes.
A warning is thrown on lint.

* ✅Add tests for logs

Author: keithrfung

mypy.ini

@@ -6,7 +6,7 @@ warn_return_any = True
 warn_unused_configs = True
 disallow_untyped_defs = True
 ignore_missing_imports = True
-follow_imports = "silent"
+follow_imports = silent
 show_column_numbers = True
 mypy_path = "src:stubs"
 

src/electionguard/logs.py

@@ -2,7 +2,7 @@
 import logging
 import os.path
 import sys
-from typing import Any, Tuple
+from typing import Any, List, Tuple
 from logging.handlers import RotatingFileHandler
 
 from .singleton import Singleton
@@ -21,8 +21,7 @@ def __init__(self) -> None:
         super(ElectionGuardLog, self).__init__()
 
         self.__logger = logging.getLogger("electionguard")
-        self.__logger.addHandler(self._get_file_handler())
-        self.__logger.addHandler(self._get_stream_handler())
+        self.__logger.addHandler(get_stream_handler())
 
     @staticmethod
     def __get_call_info() -> Tuple[str, str, int]:
@@ -45,30 +44,23 @@ def __formatted_message(self, message: str) -> str:
         message = f"{os.path.basename(filename)}.{funcname}:#L{line}: {message}"
         return message
 
-    def _get_stream_handler(self) -> logging.StreamHandler:
+    def add_handler(self, handler: logging.Handler) -> None:
         """
-        Get a Stream Handler, sends only warnings and errors to stdout.
+        Adds a logger handler
         """
-        stream_handler = logging.StreamHandler(sys.stdout)
-        stream_handler.setLevel(logging.WARNING)
-        stream_handler.setFormatter(logging.Formatter(FORMAT))
-        return stream_handler
+        self.__logger.addHandler(handler)
 
-    def _get_file_handler(self) -> logging.FileHandler:
+    def remove_handler(self, handler: logging.Handler) -> None:
         """
-        Get a File System Handler, sends verbose logging to a file, `electionguard.log`.
-        When that file gets too large, the logs will rotate, creating files with names
-        like `electionguard.log.1`.
+        Removes a logger handler
         """
+        self.__logger.removeHandler(handler)
 
-        # TODO: add file compression, save a bunch of space.
-        #   https://medium.com/@rahulraghu94/overriding-pythons-timedrotatingfilehandler-to-compress-your-log-files-iot-c766a4ace240
-        file_handler = RotatingFileHandler(
-            "electionguard.log", "a", maxBytes=10_000_000, backupCount=10
-        )
-        file_handler.setLevel(logging.DEBUG)
-        file_handler.setFormatter(logging.Formatter(FORMAT))
-        return file_handler
+    def handlers(self) -> List[logging.Handler]:
+        """
+        Returns all logging handlers
+        """
+        return self.__logger.handlers
 
     def debug(self, message: str, *args: Any, **kwargs: Any) -> None:
         """
@@ -101,9 +93,57 @@ def critical(self, message: str, *args: Any, **kwargs: Any) -> None:
         self.__logger.critical(self.__formatted_message(message), *args, **kwargs)
 
 
+def get_stream_handler() -> logging.StreamHandler:
+    """
+    Get a Stream Handler, sends only warnings and errors to stdout.
+    """
+    stream_handler = logging.StreamHandler(sys.stdout)
+    stream_handler.setLevel(logging.WARNING)
+    stream_handler.setFormatter(logging.Formatter(FORMAT))
+    return stream_handler
+
+
+def get_file_handler() -> logging.FileHandler:
+    """
+    Get a File System Handler, sends verbose logging to a file, `electionguard.log`.
+    When that file gets too large, the logs will rotate, creating files with names
+    like `electionguard.log.1`.
+    """
+
+    # TODO: add file compression, save a bunch of space.
+    #   https://medium.com/@rahulraghu94/overriding-pythons-timedrotatingfilehandler-to-compress-your-log-files-iot-c766a4ace240
+    file_handler = RotatingFileHandler(
+        "electionguard.log", "a", maxBytes=10_000_000, backupCount=10
+    )
+    file_handler.setLevel(logging.DEBUG)
+    file_handler.setFormatter(logging.Formatter(FORMAT))
+    return file_handler
+
+
 LOG = ElectionGuardLog()
 
 
+def log_add_handler(handler: logging.Handler) -> None:
+    """
+    Adds a handler to the logger
+    """
+    LOG.add_handler(handler)
+
+
+def log_remove_handler(handler: logging.Handler) -> None:
+    """
+    Removes a handler from the logger
+    """
+    LOG.remove_handler(handler)
+
+
+def log_handlers() -> List[logging.Handler]:
+    """
+    Returns all logger handlers
+    """
+    return LOG.handlers()
+
+
 def log_debug(msg: str, *args: Any, **kwargs: Any) -> None:
     """
     Logs a debug message to the console and the file log.

tests/test_logs.py

@@ -0,0 +1,47 @@
+from unittest import TestCase
+
+from electionguard.logs import (
+    get_stream_handler,
+    log_add_handler,
+    log_remove_handler,
+    log_handlers,
+    log_debug,
+    log_error,
+    log_info,
+    log_warning,
+)
+
+
+class TestLogs(TestCase):
+    def test_log_methods(self):
+        # Arrange
+        message = "test log message"
+
+        # Act
+        log_debug(message)
+        log_error(message)
+        log_info(message)
+        log_warning(message)
+
+    def test_log_handlers(self):
+        # Arrange
+
+        # Act
+        handlers = log_handlers()
+
+        # Assert
+        self.assertEqual(len(handlers), 1)
+
+        # Act
+        log_remove_handler(handlers[0])
+        empty_handlers = log_handlers()
+
+        # Assert
+        self.assertEqual(len(empty_handlers), 0)
+
+        # Act
+        log_add_handler(get_stream_handler())
+        added_handlers = log_handlers()
+
+        # Assert
+        self.assertEqual(len(added_handlers), 1)