feat: add file logging (#2023)

logs into `lnbits.log` with info loglevel and `debug.log` with DEBUG loglevel
files will be saved into `LNBITS_DATA_DIR`.
retentions is configurable but defaults to `90 days`
* added log rotation aswell

---------

Co-authored-by: Vlad Stan <stan.v.vlad@gmail.com>

.env.example

@@ -8,6 +8,13 @@ PORT=5000
 
 DEBUG=false
 
+# logging into LNBITS_DATA_FOLDER/logs/
+ENABLE_LOG_TO_FILE=true
+
+# https://loguru.readthedocs.io/en/stable/api/logger.html#file
+LOG_ROTATION="100 MB"
+LOG_RETENTION="3 months"
+
 # Server security, rate limiting ips, blocked ips, allowed ips
 LNBITS_RATE_LIMIT_NO="200"
 LNBITS_RATE_LIMIT_UNIT="minute"

lnbits/app.py

@@ -526,6 +526,23 @@ def configure_logger() -> None:
     log_level: str = "DEBUG" if settings.debug else "INFO"
     formatter = Formatter()
     logger.add(sys.stdout, level=log_level, format=formatter.format)
+
+    if settings.enable_log_to_file:
+        logger.add(
+            Path(settings.lnbits_data_folder, "logs", "lnbits.log"),
+            rotation=settings.log_rotation,
+            retention=settings.log_retention,
+            level="INFO",
+            format=formatter.format,
+        )
+        logger.add(
+            Path(settings.lnbits_data_folder, "logs", "debug.log"),
+            rotation=settings.log_rotation,
+            retention=settings.log_retention,
+            level="DEBUG",
+            format=formatter.format,
+        )
+
     logging.getLogger("uvicorn").handlers = [InterceptHandler()]
     logging.getLogger("uvicorn.access").handlers = [InterceptHandler()]
     logging.getLogger("uvicorn.error").handlers = [InterceptHandler()]

lnbits/server.py

@@ -37,6 +37,7 @@ def main(
 
     # create data dir if it does not exist
     Path(settings.lnbits_data_folder).mkdir(parents=True, exist_ok=True)
+    Path(settings.lnbits_data_folder, "logs").mkdir(parents=True, exist_ok=True)
 
     # create `extensions`` dir if it does not exist
     Path(settings.lnbits_extensions_path, "extensions").mkdir(

lnbits/settings.py

@@ -296,6 +296,9 @@ class EnvSettings(LNbitsSettings):
     lnbits_extensions_path: str = Field(default="lnbits")
     super_user: str = Field(default="")
     version: str = Field(default="0.0.0")
+    enable_log_to_file: bool = Field(default=True)
+    log_rotation: str = Field(default="100 MB")
+    log_retention: str = Field(default="3 months")
 
     @property
     def has_default_extension_path(self) -> bool: