Merge pull request #61 from FoamyGuy/formatters

Adding Formatter and example including timestamp

adafruit_logging.py

@@ -64,7 +64,7 @@
 
 try:
  # pylint: disable=deprecated-class
- from typing import Optional, Hashable
+ from typing import Optional, Hashable, Dict
  from typing_extensions import Protocol
 
  class WriteableStream(Protocol):
@@ -148,12 +148,85 @@ def _logRecordFactory(name, level, msg, args):
  return LogRecord(name, level, _level_for(level), msg, time.monotonic(), args)
 
 
+class Formatter:
+ """
+ Responsible for converting a LogRecord to an output string to be
+ interpreted by a human or external system.
+
+ Only implements a sub-set of CPython logging.Formatter behavior,
+ but retains all the same arguments in order to match the API.
+
+ The only init arguments currently supported are: fmt, defaults and
+ style. All others are currently ignored
+
+ The only two styles currently supported are '%' and '{'. The default
+ style is '{'
+ """
+
+ def __init__( # pylint: disable=too-many-arguments
+ self,
+ fmt: Optional[str] = None,
+ datefmt: Optional[str] = None,
+ style: str = "%",
+ validate: bool = True,
+ defaults: Dict = None,
+ ):
+ self.fmt = fmt
+ self.datefmt = datefmt
+ self.style = style
+ if self.style not in ("{", "%"):
+ raise ValueError(
+ "Only '%' and '{' formatting style are supported at this time."
+ )
+
+ self.validate = validate
+ self.defaults = defaults
+
+ def format(self, record: LogRecord) -> str:
+ """
+ Format the given LogRecord into an output string
+ """
+ if self.fmt is None:
+ return record.msg
+
+ vals = {
+ "name": record.name,
+ "levelno": record.levelno,
+ "levelname": record.levelname,
+ "message": record.msg,
+ "created": record.created,
+ "args": record.args,
+ }
+ if "{asctime}" in self.fmt or "%(asctime)s" in self.fmt:
+ now = time.localtime()
+ # pylint: disable=line-too-long
+ vals[
+ "asctime"
+ ] = f"{now.tm_year}-{now.tm_mon:02d}-{now.tm_mday:02d} {now.tm_hour:02d}:{now.tm_min:02d}:{now.tm_sec:02d}"
+
+ if self.defaults:
+ for key, val in self.defaults.items():
+ if key not in vals:
+ vals[key] = val
+
+ if self.style not in ("{", "%"):
+ raise ValueError(
+ "Only '%' and '{' formatting style are supported at this time."
+ )
+
+ if self.style == "%":
+ return self.fmt % vals
+
+ return self.fmt.format(**vals)
+
+
 class Handler:
  """Base logging message handler."""
 
  def __init__(self, level: int = NOTSET) -> None:
  """Create Handler instance"""
  self.level = level
+ self.formatter = None
 
  def setLevel(self, level: int) -> None:
  """
@@ -167,7 +240,8 @@ def format(self, record: LogRecord) -> str:
 
  :param record: The record (message object) to be logged
  """
-
+ if self.formatter:
+ return self.formatter.format(record)
  return f"{record.created:<0.3f}: {record.levelname} - {record.msg}"
 
  def emit(self, record: LogRecord) -> None:
@@ -182,6 +256,12 @@ def emit(self, record: LogRecord) -> None:
  def flush(self) -> None:
  """Placeholder for flush function in subclasses."""
 
+ def setFormatter(self, formatter: Formatter) -> None:
+ """
+ Set the Formatter to be used by this Handler.
+ """
+ self.formatter = formatter
+
 
 # pylint: disable=too-few-public-methods
 class StreamHandler(Handler):

examples/logging_formatter_example.py

@@ -0,0 +1,48 @@
+# SPDX-FileCopyrightText: 2024 Tim Cocks
+# SPDX-License-Identifier: MIT
+
+
+"""Illustrate usage of default and custom Formatters including
+one with timestamps."""
+
+import adafruit_logging as logging
+
+# To test on CPython, un-comment below and comment out above
+# import logging
+
+
+logger = logging.getLogger("example")
+logger.setLevel(logging.INFO)
+print_handler = logging.StreamHandler()
+logger.addHandler(print_handler)
+
+default_formatter = logging.Formatter()
+
+print_handler.setFormatter(default_formatter)
+logger.info("Default formatter example")
+
+
+timestamp_formatter = logging.Formatter(fmt="%(asctime)s %(levelname)s: %(message)s")
+print_handler.setFormatter(timestamp_formatter)
+logger.info("Timestamp formatter example")
+
+
+custom_vals_formatter = logging.Formatter(
+ fmt="%(ip)s %(levelname)s: %(message)s", defaults={"ip": "192.168.1.188"}
+)
+print_handler.setFormatter(custom_vals_formatter)
+logger.info("Custom formatter example")
+
+
+bracket_timestamp_formatter = logging.Formatter(
+ fmt="{asctime} {levelname}: {message}", style="{"
+)
+print_handler.setFormatter(bracket_timestamp_formatter)
+logger.info("Timestamp formatter bracket style example")
+
+
+bracket_custom_vals_formatter = logging.Formatter(
+ fmt="{ip} {levelname}: {message}", style="{", defaults={"ip": "192.168.1.188"}
+)
+print_handler.setFormatter(bracket_custom_vals_formatter)
+logger.info("Custom formatter bracket style example")