🎨 Improved logging

- One unlimited log file per session
- Up to 3 session logs kept at any time
- Log compressed via lzma

src/logging/session_file_handler.py

@@ -0,0 +1,70 @@
+import lzma
+from io import StringIO
+from logging import StreamHandler
+from lzma import FORMAT_XZ, PRESET_DEFAULT
+from os import PathLike
+from pathlib import Path
+
+
+class SessionFileHandler(StreamHandler):
+    """
+    A logging handler that writes to a new file on every app restart.
+    The files are compressed and older sessions logs are kept up to a small limit.
+    """
+
+    backup_count: int
+    filename: Path
+    log_file: StringIO = None
+
+    def create_dir(self) -> None:
+        """Create the log dir if needed"""
+        self.filename.parent.mkdir(exist_ok=True)
+
+    def rotate_file(self, file: Path):
+        """Rotate a file's number suffix and remove it if it's too old"""
+
+        # Skip non interesting dir entries
+        if not (file.is_file() and file.name.startswith(self.filename.name)):
+            return
+
+        # Compute the new number suffix
+        suffixes = file.suffixes
+        has_number = len(suffixes) != len(self.filename.suffixes)
+        current_number = 0 if not has_number else int(suffixes[-1][1:])
+        new_number = current_number + 1
+
+        # Rename with new number suffix
+        if has_number:
+            suffixes.pop()
+        suffixes.append(f".{new_number}")
+        stem = file.name.split(".", maxsplit=1)[0]
+        new_name = stem + "".join(suffixes)
+        print(f"Log file renamed: {file.name} -> {new_name}")
+        file = file.rename(file.with_name(new_name))
+
+        # Remove older files
+        if new_number > self.backup_count:
+            print(f"Log file deleted: {file.name}")
+            file.unlink()
+            return
+
+    def rotate(self) -> None:
+        """Rotate the numbered suffix on the log files and remove old ones"""
+        files = list(self.filename.parent.iterdir())
+        files.sort(key=lambda file: file.name, reverse=True)
+        for file in files:
+            self.rotate_file(file)
+
+    def __init__(self, filename: PathLike, backup_count: int = 2) -> None:
+        self.filename = Path(filename)
+        self.backup_count = backup_count
+        self.create_dir()
+        self.rotate()
+        self.log_file = lzma.open(
+            self.filename, "at", format=FORMAT_XZ, preset=PRESET_DEFAULT
+        )
+        super().__init__(self.log_file)
+
+    def close(self) -> None:
+        self.log_file.close()
+        super().close()

src/logging/setup.py

@@ -8,18 +8,14 @@ from src import shared
 def setup_logging():
     """Intitate the app's logging"""
 
-    # Prepare the log file
+    is_dev = shared.PROFILE == "development"
-    log_dir = shared.data_dir / "cartridges" / "logs"
+    profile_app_log_level = "DEBUG" if is_dev else "INFO"
-    log_dir.mkdir(exist_ok=True)
+    profile_lib_log_level = "INFO" if is_dev else "WARNING"
-    log_file_path = log_dir / "cartridges.log"
-    log_file_max_size_bytes = 8 * 10**6  # 8 MB
-
-    # Define log levels
-    profile_app_log_level = "DEBUG" if shared.PROFILE == "development" else "INFO"
-    profile_lib_log_level = "INFO" if shared.PROFILE == "development" else "WARNING"
     app_log_level = os.environ.get("LOGLEVEL", profile_app_log_level).upper()
     lib_log_level = os.environ.get("LIBLOGLEVEL", profile_lib_log_level).upper()
 
+    log_filename = shared.data_dir / "cartridges" / "logs" / "cartridges.log.xz"
+
     config = {
         "version": 1,
         "formatters": {
@@ -33,12 +29,11 @@ def setup_logging():
         },
         "handlers": {
             "file_handler": {
-                "class": "logging.handlers.RotatingFileHandler",
+                "class": "src.logging.session_file_handler.SessionFileHandler",
                 "formatter": "file_formatter",
                 "level": "DEBUG",
-                "filename": log_file_path,
+                "filename": log_filename,
-                "maxBytes": log_file_max_size_bytes,
+                "backup_count": 2,
-                "backupCount": 1,
             },
             "app_console_handler": {
                 "class": "logging.StreamHandler",