Add padding to levelname in terminal logs

It makes it easier to follow logs when the message part is aligned and
the level does not affect where the text starts.

The colouring method has been refactored at the same time to reduce the
duplication around adding styles.

Author: tpoliaw

src/blueapi/log.py

@@ -139,34 +139,25 @@ class IBMColorBlindSafeColors(enum.Enum):
 class ColorFormatter(logging.Formatter):
     """Colors level_name of log using IBM color blind safe palette."""
 
-    def color_level_name(self, level_name: str, level_no: int) -> str:
+    def _level_colour(self, level_no: int) -> tuple[int, int, int] | None:
         match level_no:
             case logging.DEBUG:
-                return click.style(
-                    str(level_name), fg=IBMColorBlindSafeColors.ultramarine.value
-                )
+                return IBMColorBlindSafeColors.ultramarine.value
             case logging.INFO:
-                return click.style(
-                    str(level_name), fg=IBMColorBlindSafeColors.indigo.value
-                )
+                return IBMColorBlindSafeColors.indigo.value
             case logging.WARNING:
-                return click.style(
-                    str(level_name), fg=IBMColorBlindSafeColors.gold.value
-                )
+                return IBMColorBlindSafeColors.gold.value
             case logging.ERROR:
-                return click.style(
-                    str(level_name), fg=IBMColorBlindSafeColors.magenta.value
-                )
+                return IBMColorBlindSafeColors.magenta.value
             case logging.CRITICAL:
-                return click.style(
-                    str(level_name), fg=IBMColorBlindSafeColors.orange.value
-                )
-        return level_name
+                return IBMColorBlindSafeColors.orange.value
+            case _:
+                return None
 
     def formatMessage(self, record: logging.LogRecord) -> str:  # noqa: N802
         # Copy record to avoid modifying for other handlers etc.
         recordcopy = copy(record)
-        recordcopy.levelname = self.color_level_name(
-            recordcopy.levelname, recordcopy.levelno
+        recordcopy.levelname = click.style(
+            f"{recordcopy.levelname:>8}", fg=self._level_colour(recordcopy.levelno)
         )
         return super().formatMessage(recordcopy)

tests/unit_tests/test_log.py

@@ -142,43 +142,52 @@ def foo_record():
 
 
 class TestColorFormatter:
+    def _update_record(self, record: logging.LogRecord, level: int):
+        record.levelno = level
+        record.levelname = logging.getLevelName(level)
+
     def test_debug(self, color_formatter, foo_record):
-        foo_record.levelno = logging.DEBUG
+        self._update_record(foo_record, logging.DEBUG)
 
         assert (
             color_formatter.format(foo_record)
-            == "\x1b[38;2;100;143;255mINFO\x1b[0m foo"
+            == "\x1b[38;2;100;143;255m   DEBUG\x1b[0m foo"
         )
 
     def test_info(self, color_formatter, foo_record):
-        foo_record.levelno = logging.INFO
+        self._update_record(foo_record, logging.INFO)
 
         assert (
-            color_formatter.format(foo_record) == "\x1b[38;2;120;94;240mINFO\x1b[0m foo"
+            color_formatter.format(foo_record)
+            == "\x1b[38;2;120;94;240m    INFO\x1b[0m foo"
         )
 
     def test_warning(self, color_formatter, foo_record):
-        foo_record.levelno = logging.WARNING
+        self._update_record(foo_record, logging.WARNING)
 
         assert (
-            color_formatter.format(foo_record) == "\x1b[38;2;255;176;0mINFO\x1b[0m foo"
+            color_formatter.format(foo_record)
+            == "\x1b[38;2;255;176;0m WARNING\x1b[0m foo"
         )
 
     def test_error(self, color_formatter, foo_record):
-        foo_record.levelno = logging.ERROR
+        self._update_record(foo_record, logging.ERROR)
 
         assert (
-            color_formatter.format(foo_record) == "\x1b[38;2;220;38;127mINFO\x1b[0m foo"
+            color_formatter.format(foo_record)
+            == "\x1b[38;2;220;38;127m   ERROR\x1b[0m foo"
         )
 
     def test_critical(self, color_formatter, foo_record):
-        foo_record.levelno = logging.CRITICAL
+        self._update_record(foo_record, logging.CRITICAL)
 
         assert (
-            color_formatter.format(foo_record) == "\x1b[38;2;254;97;0mINFO\x1b[0m foo"
+            color_formatter.format(foo_record)
+            == "\x1b[38;2;254;97;0mCRITICAL\x1b[0m foo"
         )
 
     def test_other(self, color_formatter, foo_record):
         foo_record.levelno = -1
+        foo_record.levelname = "UNKNOWN"
 
-        assert color_formatter.format(foo_record) == "INFO foo"
+        assert color_formatter.format(foo_record) == " UNKNOWN\x1b[0m foo"