How to logging to a file in Lilya?

[ockan]

in Lilya,StandardLoggingConfig() use the following config

def default_config(self) -> dict[str, Any]:  # noqa
        return {
            "version": 1,
            "disable_existing_loggers": False,
            "formatters": {
                "default": {
                    "format": "[%(asctime)s] %(levelname)s in %(module)s: %(message)s",
                },
            },
            "handlers": {
                "console": {
                    "class": "logging.StreamHandler",
                    "formatter": "default",
                },
            },
            "root": {
                "level": self.level,
                "handlers": ["console"],
            },
        }

it print the log info in console.
How to logging to a file?
I use:

"handlers": {
                "console": {
                    "class": "logging.StreamHandler",
                    "formatter": "default",
                },
                "file": {
                    "class": "logging.RotatingFileHandler",
                    "filename": "app.log",
                    "maxBytes": 2000,
                    "backupCount": 3,
                    "encoding": "utf-8",
                    "formatter": "default",
                },
            },

but got an error

[tarsil]

Ok, so what do you really want to do? Because that is a dict config issue, not a Lilya one

[ockan]

I rewrote logging_config() in settings_module AppSettings:

    @property
    def logging_config(self):
        config = {
            "version": 1,
            "disable_existing_loggers": False,
            "formatters": {
                "default": {
                    "format": "[%(asctime)s] %(levelname)s in %(module)s: %(message)s",
                },
            },
            "handlers": {
                "console": {
                    "class": "logging.StreamHandler",
                    "formatter": "default",
                },
                "file": {
                    "class": "logging.handlers.RotatingFileHandler",
                    "filename": "app.log",
                    "maxBytes": 10485760,
                    "backupCount": 3,
                    "encoding": "utf-8",
                    # "level": "INFO",
                    "formatter": "default",
                },
            },
            "root": {
                "level": "INFO",
                "handlers": ["console", "file"],
            },
        }
        return StandardLoggingConfig(config=config)

then

app = Lilya(settings_module=AppSettings)

and then

@app.get('/')
async def homepage(request):
    import logging

    print(f"Logger name: {logger.name}")
    print(f"Logger propagate: {logger.propagate}")
    print(f"Logger handlers: {logger.handlers}")
    print(f"Root logger handlers: {logging.getLogger().handlers}")
    logger.info("This is a log message.")
    logger.error("This is an error log.")
    return TemplateResponse(request, "index/index.html")

it only output in console:

Logger name: lilya
Logger propagate: True
Logger handlers: []
Root logger handlers: [<StreamHandler <stderr> (NOTSET)>]
[2025-09-06 14:58:40,700] INFO in main: This is a log message.
[2025-09-06 14:58:40,700] ERROR in main: This is an error log.

no file 'app.log' created

[ockan]

and after I add a line setup_logging(AppSettings().logging_config) to app.get('/') as following

@app.get('/')
async def homepage(request):
    setup_logging(AppSettings().logging_config)
    import logging

    print(f"Logger name: {logger.name}")
    print(f"Logger propagate: {logger.propagate}")
    print(f"Logger handlers: {logger.handlers}")
    print(f"Root logger handlers: {logging.getLogger().handlers}")
    logger.info("This is a log message.")
    logger.error("This is an error log.")

    return TemplateResponse(request, "index/index.html")

it output in console:

[2025-09-06 15:17:33,069] INFO in main: This is a log message.
[2025-09-06 15:17:33,069] ERROR in main: This is an error log.
Logger name: lilya
Logger propagate: True
Logger handlers: []
Root logger handlers: [<StreamHandler <stderr> (NOTSET)>, <RotatingFileHandler D:\py\lilya\work\app.log (NOTSET)>]

and wrote to file 'app.log'

[2025-09-06 15:17:33,069] INFO in main: This is a log message.
[2025-09-06 15:17:33,069] ERROR in main: This is an error log.

[ockan]

so I have to write code in in settings_module AppSettings:

async def before_request(scope, receive, send):
    setup_logging(AppSettings().logging_config)

class AppSettings(Settings):
   ...
   before_request = [before_request]

to resolve it