feat: Logging as a systemd service

docs/env.md

@@ -13,12 +13,9 @@ GALLIA_CONFIG
 : The path to the config file usually called `gallia.toml`.
   Disables autodiscovery of the config.
 
-GALLIA_LOGLEVEL
-: When {meth}`gallia.log.setup_logging()` is called without an argument this environment variable is read to set the loglevel.
-  Supported value are: `trace`, `debug`, `info`, `notice`, `warning`, `error`, `critical`.
-  As an alternative, the int values from 0 to 7 can be used.
-  Mostly useful in own scripts or tests.
-  This variable is not read when using the gallia cli.
+GALLIA_LOGGING_SYSTEMD
+: Tells gallia to omit colors and status bars in logging output.
+  Additionally, the priority information gets added such that the journal can add it.
 
 NO_COLOR
 : If this variable is set, `gallia` by default does not use color codes, see: https://no-color.org/

src/gallia/log.py

@@ -243,18 +243,12 @@ def setup_logging(
     logging.
 
     :param level: The loglevel to enable for the console handler.
-                  If this argument is None, the env variable
-                  ``GALLIA_LOGLEVEL`` (see :doc:`../env`) is read.
     :param file_level: The loglevel to enable for the file handler.
     :param path: The path to the logfile containing json records.
     :param color_mode: The color mode to use for the console.
     """
     if level is None:
-        # FIXME why is this here and not in config?
-        if (raw := os.getenv("GALLIA_LOGLEVEL")) is not None:
-            level = PenlogPriority.from_str(raw).to_level()
-        else:
-            level = Loglevel.DEBUG
+        level = Loglevel.DEBUG
 
     # These are slow and not used by gallia.
     logging.logMultiprocessing = False
@@ -344,9 +338,9 @@ class _PenlogRecordV2(msgspec.Struct, omit_defaults=True, tag=2, tag_field="vers
 _PenlogRecord: TypeAlias = _PenlogRecordV2
 
 
-def _colorize_msg(data: str, levelno: int) -> tuple[str, int]:
+def _colorize_msg(data: str, levelno: int) -> str:
     if sys.platform == "win32" or not sys.stderr.isatty():
-        return data, 0
+        return data
 
     out = ""
     match levelno:
@@ -371,7 +365,12 @@ def _colorize_msg(data: str, levelno: int) -> tuple[str, int]:
     out += data
     out += _Color.RESET.value
 
-    return out, len(style)
+    return out
+
+
+def _delete_cur_line() -> None:
+    sys.stderr.write("\33[2K\r")
+    sys.stderr.flush()
 
 
 def _format_record(  # noqa: PLR0913
@@ -384,36 +383,49 @@ def _format_record(  # noqa: PLR0913
     colored: bool = False,
     volatile_info: bool = False,
 ) -> str:
+    systemd = True if "GALLIA_LOGGING_SYSTEMD" in os.environ else False
+    if systemd:
+        colored = False
+        volatile_info = False
+
+    delete_line = volatile_info and levelno <= Loglevel.INFO
+    if delete_line:
+        _delete_cur_line()
+
     msg = ""
-    if volatile_info:
-        msg += "\33[2K"
-    extra_len = 4
-    msg += dt.strftime("%b %d %H:%M:%S.%f")[:-3]
-    msg += " "
+
+    # Add the priority info for the systemd journal…
+    if systemd:
+        msg += f"<{PenlogPriority.from_level(levelno).value}>"
+    # …else add timestamps if gallia runs under a terminal.
+    else:
+        msg += f"{dt.strftime('%b %d %H:%M:%S.%f')[:-3]} "
+
     msg += name
     if tags is not None and len(tags) > 0:
         msg += f" [{', '.join(tags)}]"
     msg += ": "
 
     if colored:
-        tmp_msg, extra_len_tmp = _colorize_msg(data, levelno)
-        msg += tmp_msg
-        extra_len += extra_len_tmp
+        msg += _colorize_msg(data, levelno)
     else:
         msg += data
 
-    if volatile_info and levelno <= Loglevel.INFO:
-        terminal_width, _ = shutil.get_terminal_size()
-        msg = msg[: terminal_width + extra_len - 1]  # Adapt length to invisible ANSI colors
-        msg += _Color.RESET.value
-        msg += "\r"
-    else:
-        msg += "\n"
-
     if stacktrace is not None:
         msg += "\n"
         msg += stacktrace
 
+    if delete_line:
+        # Truncate the line that gets deleted in
+        # in case the terminal wraps the line.
+        cols, _ = shutil.get_terminal_size()
+        msg = msg[:cols]
+        if colored:
+            msg = msg[:-2] + _Color.RESET.value
+        msg += "\r"
+    else:
+        msg += "\n"
+
     return msg