This commit is contained in:
John Lancaster
2026-06-19 17:40:04 -05:00
parent 5c4de7b721
commit 85eb75d188
+22 -12
View File
@@ -12,12 +12,14 @@ Load references only when needed:
- Python logging overview and hierarchy: [Python logging references](./references/python-logging-docs.md)
## When to Use
- A project configures logging ad hoc with `basicConfig` across multiple modules.
- You need one canonical logging configuration for app startup.
- You need consistent formatting and levels across console/file handlers.
- You want library modules to use named loggers without configuring logging themselves.
## Inputs To Collect
1. Runtime type: script, library, web app, worker, CLI.
2. Destinations: stdout only, file only, or both.
3. Desired default level: `INFO`, `DEBUG`, etc.
@@ -30,6 +32,7 @@ If missing, assume:
- `disable_existing_loggers: False`
## Procedure
1. Define a single `LOGGING` dictionary in one startup-oriented module (for example `logging_config.py`).
2. Include `version: 1` and set `disable_existing_loggers: False` unless there is a specific reason to silence existing loggers.
3. Define formatters first, then handlers, then logger routing (`root` and optional named `loggers`).
@@ -38,24 +41,28 @@ If missing, assume:
6. Keep libraries configuration-free: libraries should emit logs, applications decide routing.
7. Verify behavior with a quick smoke check at multiple levels (`DEBUG`, `INFO`, `WARNING`, `ERROR`).
## Minimal Baseline Template
```python
# logging_config.py
from logging.config import dictConfig
## Minimal Baseline Templates
### Configuration
!!! warning "Don't use the name `logging.py` because it will conflict
```python title="logging_config.py"
import logging.config
LOGGING = {
"version": 1,
"disable_existing_loggers": False,
"formatters": {
"standard": {
"format": "%(asctime)s %(levelname)s %(name)s: %(message)s"
"basic": {
"format": "%(asctime)s.%(msecs)03d [%(levelname)s] %(message)s",
"datefmt": "%Y-%m-%d %H:%M:%S",
}
},
"handlers": {
"console": {
"class": "logging.StreamHandler",
"level": "INFO",
"formatter": "standard",
"formatter": "basic",
"stream": "ext://sys.stdout",
}
},
@@ -66,22 +73,24 @@ LOGGING = {
}
def configure_logging() -> None:
dictConfig(LOGGING)
logging.config.dictConfig(LOGGING)
```
```python
```python title="app.py"
# app startup
from .logging_config import configure_logging
configure_logging()
```
### Usage
The preferred way of instantiating loggers is at the top of modules like this:
```python
# any module
import logging
logger = logging.getLogger(__name__)
logger.info("module initialized")
```
## Completion Checks
@@ -90,6 +99,7 @@ logger.info("module initialized")
3. Modules use `getLogger(__name__)`.
4. Logs appear at expected level and destination.
5. Third-party logger noise is intentionally configured or left at defaults.
6. No module named `logging.py` in the project.
## Branching Guidance
- If structured logs are required: switch formatter output to JSON while keeping `dictConfig` topology unchanged.