Yogger

Yogger provides a minimal logging setup with utilities to represent interpreter stacks.

Supports requests.Request and requests.Response objects if the Requests package is installed.

Example of common usage:

import logging
import yogger

logger = logging.getLogger(__name__)

def main():
    yogger.install()
    yogger.configure(__name__, verbosity=2, dump_locals=True)
    with yogger.dump_on_exception():
        # Code goes here

if __name__ == "__main__":
    main()

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Requirements:

Yogger requires Python 3.10 or higher, is platform independent, and has no outside dependencies.

Issue reporting

If you discover an issue with Yogger, please report it at https://github.com/Phosmic/yogger/issues.

License

This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program. If not, see https://www.gnu.org/licenses/.

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Requirements Installing Usage Library

Installing

Most stable version from PyPi:

python3 -m pip install yogger

Development version from GitHub:

git clone git+https://github.com/Phosmic/yogger.git
cd yogger
python3 -m pip install -e .

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Usage

Import packages and instantiate a logger:

import logging
import yogger

logger = logging.getLogger(__name__)

Install the logger class and configure with your package name:

Place at the start of the top-level function.

def main():
    yogger.install()
    yogger.configure(__name__)
    # Code goes here

Output

Example of logger output:

[ 2023-01-17 10:16:09.0918  INFO  my_package ]  Something we want to log.
[ 2023-01-17 10:16:09.0918  DEBUG  my_package ]  Something we want to log.
[ 2023-01-17 10:16:09.0918  WARNING  my_package ]  Something we want to log.
[ 2023-01-17 10:16:09.0918  ERROR  my_package ]  Something we want to log.`
[ 2023-01-17 10:16:09.0918  CRITICAL  my_package ]  Something we want to log.

Note: Support for rich text has not yet been added for Windows platforms.

Support for dumping the stack

Traces and exceptions

Using the dump_on_exception context manager dumps the exception and trace if an exception is raised:

with yogger.dump_on_exception(
    # Uncomment to override
    # dump_path="./stack_dump.txt",
):
    raise SomeException

This is nearly equivalent to:

import inspect

try:
    raise SomeException
except Exception as e:
    trace = inspect.trace()
    if len(trace) > 1:
        with open("./stack_dump.txt", mode="a", encoding="utf-8") as f:
            yogger.dump(f, trace[1:], e=e, package_name="my_package")

Stacks

Setting dump_locals=True when running yogger.configure dumps a representation of the caller's stack upon logging with a level of warning or higher.

To manually dump the stack, something like this would suffice:

import inspect

stack = inspect.stack()
if len(stack) > 2:
    with open("./example.log", mode="w", encoding="utf-8") as f:
        yogger.dump(f, stack[2:][::-1])

If you simply want the string representation, use the yogger.dumps function:

stack = inspect.stack()
if len(stack) > 2:
    trace_repr = yogger.dumps(stack[2:][::-1])

Output

Example of dictionary representation in dump:

example = {
    "user_id": 123456790,
    "profile": {
        "name": "John Doe",
        "birthdate": datetime.date(2000, 1, 1),
        "weight_kg": 86.18,
    },
    "video_ids": [123, 456, 789],
}

example = <builtins.dict>
  example['user_id'] = 123456790
  example['profile'] = <builtins.dict>
    example['profile']['name'] = 'John Doe'
    example['profile']['birthdate'] = datetime.date(2000, 1, 1)
    example['profile']['weight_kg'] = 86.18
  example['video_ids'] = [123, 456, 789]

Similarly for a dataclass:

@dataclasses.dataclass
class Example:
    user_id: int
    profile: dict[str, str | float | datetime.date]
    video_ids: list[int]

example = <my_package.Example>
  example.user_id = 'user_id' = example.user_id = 123456790
  example.profile = 'profile' = example.profile = <builtins.dict>
    example.profile['name'] = 'John Doe'
    example.profile['birthdate'] = datetime.date(2000, 1, 1)
    example.profile['weight_kg'] = 86.18
  example.video_ids = 'video_ids' = example.video_ids = [123, 456, 789]

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Library

About the package_name parameter

The package_name parameter gives Yogger an idea of what belongs to your application. This name is used to identify which frames to dump in the stack. So it’s important what you provide there. If you are using a single module, __name__ is always the correct value. If you are using a package, it’s usually recommended to hardcode the name of your package there.

For example, if your application is defined in "my_package/app.py", you should create it with one of the two versions below:

yogger.configure("my_package")

yogger.configure(__name__.split(".")[0])

Why is that? The application will work even with __name__, thanks to how resources are looked up. However, it will make debugging more painful. Yogger makes assumptions based on the import name of your application. If the import name is not properly set up, that debugging information may be lost.

yogger.pformat

Create a formatted representation of a variable's name and value.

This module is used to create a formatted representation of a variable's name and value.

pformat

def pformat(name: str,
            value: Any,
            outer_line_continuation: bool = True) -> str

Create a formatted representation of a variable's name and value.

Arguments:

• name str - Name of the variable to represent.
• value Any - Value to represent.
• outer_line_continuation bool, optional - Whether the outermost representation should be line continued. Defaults to True.

Returns:

• str - Formatted representation of a variable's name and value.

yogger.base

Yogger Base Module

This module contains the base classes and functions for Yogger.

Yogger Objects

class Yogger(logging.Logger)

Yogger Logger Class

This class is used to override the default logging.Logger class.

install

def install() -> None

Install the Yogger Logger Class and Instantiate the Global Logger

configure

def configure(package_name: str,
              *,
              verbosity: int = 0,
              dump_locals: bool = False,
              dump_path: str | bytes | os.PathLike | None = None,
              remove_handlers: bool = True) -> None

Prepare for Logging

Arguments:

• package_name str - Name of the package to dump from the stack.
• verbosity int, optional - Level of verbosity (0-2) for log messages. Defaults to 0.
• dump_locals bool, optional - Dump the caller's stack when logging with a level of warning or higher. Defaults to False.
• dump_path str | bytes | os.PathLike, optional - Custom path to use when dumping with 'dump_on_exception' or when 'dump_locals=True', otherwise use a temporary path if None. Defaults to None.
• remove_handlers bool, optional - Remove existing logging handlers before adding the new stream handler. Defaults to True.

dumps

def dumps(stack: list[inspect.FrameInfo],
          *,
          err: Exception | None = None,
          package_name: str | None = None) -> str

Create a String Representation of an Interpreter Stack

Externalizes '_stack_dumps' to be accessed by the user.

Arguments:

• stack list[inspect.FrameInfo] - Stack of frames to represent.
• err Exception | None, optional - Exception that was raised. Defaults to None.
• package_name str | None, optional - Name of the package to dump from the stack, otherwise non-exclusive if set to None. Defaults to None.

Returns:

• str - Representation of the stack.

dump

def dump(fp: io.TextIOBase | io.BytesIO,
         stack: list[inspect.FrameInfo],
         *,
         err: Exception | None = None,
         package_name: str | None = None) -> None

Write the Representation of an Interpreter Stack using a File Object

Arguments:

• fp io.TextIOBase | io.BytesIO - File object to use for writing.
• stack list[inspect.FrameInfo] - Stack of frames to dump.
• err Exception | None, optional - Exception that was raised. Defaults to None.
• package_name str | None, optional - Name of the package to dump from the stack, otherwise non-exclusive if set to None. Defaults to None.

dump_on_exception

@contextlib.contextmanager
def dump_on_exception(
    dump_path: str | bytes | os.PathLike | None = None
) -> Generator[None, None, None]

Content Manager to Dump if an Exception is Raised

Writes a representation of the exception and trace stack to file.

Arguments:

• dump_path str | bytes | os.PathLike | None, optional - Override the file path to use for the dump. Defaults to None.

Yields:

• Generator[None, None, None] - Context manager.

Raises:

• Exception - Exception that was raised.

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