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flake8-logging-format

(★ 137)

Flake8 extension to validate (lack of) logging format strings

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Download Latest Version (.zip)

- - codeql.yml
- build.json
- - __init__.py
  - test_visitor.py
  - test_whitelist.py
- __init__.py
- api.py
- violations.py
- visitor.py
- whitelist.py
.ackrc
.bumpversion.cfg
.dockerignore
.drone.yml
.gitignore
CONTRIBUTING.md
Dockerfile
entrypoint.sh
LICENSE
MANIFEST.in
README.md
setup.cfg
setup.py

# Installation Guide

1. Get the code

git clone https://github.com/globality-corp/flake8-logging-format

Downloads the entire project code from GitHub to your computer.

cd flake8-logging-format

Moves into the project folder you just downloaded.

2. Docker

Easy Recommended

Prerequisites

Git Needed to download the project code from GitHub.
Docker Desktop Needed to build and run containers. Install it and keep it running in the background.

docker build -t flake8-logging-format .

Builds a runnable image based on the Dockerfile.

docker run -p 8080:80 flake8-logging-format

Runs the built image as an actual container.

✅ Run docker compose ps to check the containers are Up. If the README mentions a port, open http://localhost:PORT in your browser.

3. Python

Easy

Prerequisites

Git Needed to download the project code from GitHub.
Python 3 On Windows, be sure to check 'Add Python to PATH' during installation.

pip install .

Installs the package published on PyPI directly — no need to clone the source.

python <실행할 파일명>.py # README에서 정확한 실행 파일명을 확인하세요

Runs the Python script (or module).

✅ If it runs without errors and prints output in the terminal, it worked.

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# flake8-logging-format

Flake8 extension to validate (lack of) logging format strings

## What's This?

Python [logging](https://docs.python.org/3/library/logging.html#logging.Logger.debug) supports a special `extra` keyword
for passing a dictionary of user-defined attributes to include in a logging event. One way to ensure consistency and
rigor in logging is to **always** use `extra` to pass non-constant data and, therefore, to **never** use format strings,
concatenation, or other similar techniques to construct a log string.

In other words, do this:

```python
logger.info(
    "Hello {world}",
    extra=dict(
        world="Earth"
    )
)
```

Instead of:

```python
logger.info(
    "Hello {world}".format(world=Earth)
)
```

## Extra Whitelist

As a further level of rigor, we can enforce that `extra` dictionaries only use keys from a well-known whitelist.

Usage:

```bash
flake8 --enable-extra-whitelist
```

The built-in `Whitelist` supports plugins using `entry_points` with a key of `"logging.extra.whitelist"`. Each
registered entry point must be a callable that returns an iterable of string.

In some cases you may want to log sensitive data only in debugging scenarios.  This is supported in 2 ways:
1. We do not check the logging.extra.whitelist for lines logged at the `debug` level
2. You may also prefix a keyword with 'debug\_' and log it at another level.  You can safely assume these will be
   filtered out of shipped logs.

## Violations Detected

-  `G001` Logging statements should not use `string.format()` for their first argument
 -  `G002` Logging statements should not use `%` formatting for their first argument
 -  `G003` Logging statements should not use `+` concatenation for their first argument
 -  `G004` Logging statements should not use `f"..."` for their first argument (only in Python 3.6+)
 -  `G010` Logging statements should not use `warn` (use `warning` instead)
 -  `G100` Logging statements should not use `extra` arguments unless whitelisted
 -  `G101` Logging statement should not use `extra` arguments that clash with LogRecord fields
 -  `G200` Logging statements should not include the exception in logged string (use `exception` or `exc_info=True`)
 -  `G201` Logging statements should not use `error(..., exc_info=True)` (use `exception(...)` instead)
 -  `G202` Logging statements should not use redundant `exc_info=True` in `exception`

These violations are disabled by default. To enable them for your project, specify the code(s) in your `setup.cfg`:

```ini
[flake8]
enable-extensions=G
```

## Motivation

Our motivation has to do with balancing the needs of our team and those of our customers.
On the one hand, developers and front-line support should be able to look at application logs. On the other hand, our customers don't want their data shared with anyone, including internal employees.

The implementation approaches this in two ways:

1. By trying to prevent the use of string concatenation in logs (vs explicit variable passing in the standard logging `extra` dictionary)

2. By providing an (optional) mechanism for whitelisting which field names may appear in the `extra` dictionary

Naturally, this _does not_ prevent developers from doing something like:

```python
extra=dict(
    user_id=user.name,
)
```

but then avoiding a case like this falls back to other processes around pull-requests, code review and internal policy.