Logging¶

Tesserae logs with loguru. It uses loguru's shared logger and adds no output of its own, so its messages go wherever your app's loguru setup sends them. With no setup at all, that's loguru's default output on stderr, so you see them straight away.

Setting up the console¶

configure_logging() is a one-call setup for app.py:

from loguru import logger

from tesserae import App, configure_logging

configure_logging()          # INFO and above, Tesserae's format
# configure_logging("DEBUG") # also shows loads, screen switches, tracebacks

logger.info("starting")      # your own messages use the same logger

The output looks like:

12:48:27.553 | INFO     | tesserae.spec.watch - reloaded /path/to/Home_View.yaml

configure_logging replaces loguru's default stderr handler and leaves any handler you added yourself. It takes level, sink (anything logger.add accepts: a stream, a file path, a function) and format (tesserae.log.DEFAULT_FORMAT by default), and returns the handler id.

What Tesserae logs¶

Level	Message
`DEBUG`	a screen loaded (`app.load`), a screen shown (`app.show`), the traceback of a failed hot reload
`INFO`	hot reload started, and what it watches; each view reloaded; each theme or stylesheet file applied
`WARNING`	Python warnings such as `FontFallbackWarning`, when `configure_logging` captures them (below)
`ERROR`	a hot reload that failed, naming the file and the error

Each message carries the Tesserae module it came from (tesserae.app, tesserae.spec.watch), which loguru shows as {name}.

Failed hot reloads¶

When a background reload fails, from a YAML error, an unknown component, or a spec or stylesheet tre rejects, Tesserae logs one ERROR line naming the file. The traceback is logged at DEBUG, so a typo doesn't print a stack trace unless you ask for one. The screen stays as it was, and the app and the watcher keep running. ViewWatcher.poll(), which your own loop calls, still raises instead.

Warnings¶

FontFallbackWarning is a real Python warning, so warnings.filterwarnings("error", category=FontFallbackWarning) still turns it into an exception. By default, configure_logging also shows warnings through loguru, so they appear in the same format as everything else. Pass capture_warnings=False to leave Python's own warning output alone.

Turning Tesserae's messages off¶

from loguru import logger

logger.disable("tesserae")                 # everything from Tesserae
logger.disable("tesserae.spec.watch")      # just hot reload

logger.enable("tesserae") turns them back on.