log rotation based on env variable

Author: juztas

Makefile

@@ -5,6 +5,8 @@ UV          := uv
 PIP         := $(BIN)/pip
 LOG_FILE    := runtime-logs.log
 IRI_LOG_FILE ?= $(LOG_FILE)
+LOG_ROTATION_DAYS := 5
+IRI_LOG_ROTATION_DAYS ?= $(LOG_ROTATION_DAYS)
 
 STAMP_VENV  := $(VENV)/.created
 STAMP_DEPS  := $(VENV)/.deps
@@ -37,6 +39,7 @@ dev: deps
 	IRI_API_ADAPTER_filesystem=app.demo_adapter.DemoAdapter \
 	IRI_API_ADAPTER_task=app.demo_adapter.DemoAdapter \
 	IRI_LOG_FILE="$${IRI_LOG_FILE:-$${LOG_FILE:-$(IRI_LOG_FILE)}}" \
+	IRI_LOG_ROTATION_DAYS="$${IRI_LOG_ROTATION_DAYS:-$${LOG_ROTATION_DAYS:-$(IRI_LOG_ROTATION_DAYS)}}" \
 	DEMO_QUEUE_UPDATE_SECS=2 \
 	OPENTELEMETRY_ENABLED=true \
 	API_URL_ROOT='http://localhost:8000' fastapi dev

README.md

@@ -62,8 +62,10 @@ Links to data, created by this api, will concatenate these values producing link
 - `LOG_LEVEL`: logging level for the API and adapters. Defaults to `DEBUG`.
 - `IRI_LOG_FILE`: file path for API logs. Logs always go to stdout; when this is set, logs also go to the file.
 - `LOG_FILE`: fallback file path for API logs when `IRI_LOG_FILE` is not set.
+- `IRI_LOG_ROTATION_DAYS`: number of daily rotated log files to retain. Defaults to `5`.
+- `LOG_ROTATION_DAYS`: fallback retention when `IRI_LOG_ROTATION_DAYS` is not set.
 
-For local development, `make` writes logs to `runtime-logs.log` by default. Use `make LOG_FILE=/tmp/iri-api.log` or `make IRI_LOG_FILE=/tmp/iri-api.log` to choose a different file. You can also put either variable in `local.env`.
+For local development, `make` writes logs to `runtime-logs.log` by default and keeps `5` daily rotated files. Use `make LOG_FILE=/tmp/iri-api.log`, `make IRI_LOG_FILE=/tmp/iri-api.log`, or `make LOG_ROTATION_DAYS=10` to override those defaults. You can also put the same variables in `local.env`.
 
 ## Docker support
 

app/apilogger.py

@@ -3,6 +3,7 @@
 import logging
 import os
 import sys
+from logging.handlers import TimedRotatingFileHandler
 from pathlib import Path
 
 LEVELS = {"FATAL": logging.FATAL,
@@ -14,6 +15,7 @@
 DEFAULT_FORMAT = "%(asctime)s.%(msecs)03d - %(name)s - %(levelname)s - %(message)s"
 DEFAULT_DATE_FORMAT = "%a, %d %b %Y %H:%M:%S"
 IRI_HANDLER_ATTR = "_iri_facility_api_handler"
+DEFAULT_ROTATION_DAYS = 5
 
 _CONFIGURED = False
 
@@ -29,6 +31,15 @@ def _log_file_path() -> Path | None:
     return Path(log_file) if log_file else None
 
 
+def _rotation_days() -> int:
+    raw_days = os.environ.get("IRI_LOG_ROTATION_DAYS") or os.environ.get("LOG_ROTATION_DAYS")
+    try:
+        days = int(raw_days) if raw_days is not None else DEFAULT_ROTATION_DAYS
+    except ValueError:
+        days = DEFAULT_ROTATION_DAYS
+    return max(days, 0)
+
+
 def configure_logging(level: str | int | None = None) -> None:
     """
     Configure root logging for the API.
@@ -65,7 +76,13 @@ def configure_logging(level: str | int | None = None) -> None:
     if log_file:
         if log_file.parent != Path("."):
             log_file.parent.mkdir(parents=True, exist_ok=True)
-        file_handler = logging.FileHandler(log_file)
+        file_handler = TimedRotatingFileHandler(
+            log_file,
+            when="midnight",
+            interval=1,
+            backupCount=_rotation_days(),
+            encoding="utf-8",
+        )
         file_handler.setLevel(log_level)
         file_handler.setFormatter(formatter)
         setattr(file_handler, IRI_HANDLER_ATTR, True)