Replace dateutil.tz with ZoneInfo and tzlocal for better cross-platfo…

…rm compatibility. (#40)

pyproject.toml

@@ -13,9 +13,11 @@ description = "Logging/encoding/decoding using CLP's IR stream format"
 readme = "README.md"
 requires-python = ">=3.7"
 dependencies = [
+    "backports.zoneinfo >= 0.2.1; python_version < '3.9'",
     "clp-ffi-py >= 0.0.11",
-    "python-dateutil >= 2.7.0",
     "typing-extensions >= 3.7.4",
+    "tzlocal == 5.1; python_version < '3.8'",
+    "tzlocal >= 5.2; python_version >= '3.8'",
     "zstandard >= 0.18.0",
 ]
 classifiers = [

src/clp_logging/handlers.py

@@ -4,7 +4,6 @@
 import sys
 import time
 from abc import ABCMeta, abstractmethod
-from datetime import tzinfo
 from math import floor
 from pathlib import Path
 from queue import Empty, Queue
@@ -13,7 +12,7 @@
 from types import FrameType
 from typing import Callable, ClassVar, Dict, IO, Optional, Tuple, Union
 
-import dateutil.tz
+import tzlocal
 from clp_ffi_py.ir import FourByteEncoder
 from zstandard import FLUSH_FRAME, ZstdCompressionWriter, ZstdCompressor
 
@@ -59,12 +58,11 @@ def _init_timeinfo(fmt: Optional[str], tz: Optional[str]) -> Tuple[str, str]:
     if not fmt:
         fmt = "yyyy-MM-d H:m:s.A"
     if not tz:
-        tzf: Optional[tzinfo] = dateutil.tz.gettz()
-        if tzf:
-            tzp: Path = Path.resolve(Path(tzf._filename))  # type: ignore
-            tz = "/".join([tzp.parent.name, tzp.name])
-        else:
+        try:
+            tz = tzlocal.get_localzone_name()
+        except Exception:
             tz = "UTC"
+
     return fmt, tz
 
 

src/clp_logging/readers.py

@@ -1,11 +1,10 @@
 from abc import ABCMeta, abstractmethod
-from datetime import datetime, tzinfo
+from datetime import datetime
 from pathlib import Path
 from sys import stderr
 from types import TracebackType
 from typing import IO, Iterator, List, Match, Optional, Tuple, Type, Union
 
-import dateutil.tz
 from clp_ffi_py.ir import FourByteEncoder
 from zstandard import ZstdDecompressionReader, ZstdDecompressor
 
@@ -31,6 +30,13 @@
     VAR_COMPACT_ENCODING,
 )
 
+try:
+    from zoneinfo import ZoneInfo  # type: ignore[import-not-found, unused-ignore]
+except ImportError:
+    from backports.zoneinfo import (  # type: ignore[import-not-found, no-redef, unused-ignore]
+        ZoneInfo,
+    )
+
 
 class Log:
     """
@@ -61,7 +67,7 @@ def __init__(self) -> None:
     def __str__(self) -> str:
         return self.formatted_msg
 
-    def _decode(self, timestamp_format: Optional[str], timezone: Optional[tzinfo]) -> int:
+    def _decode(self, timestamp_format: Optional[str], timezone: Optional[ZoneInfo]) -> int:
         """
         Populate the `variables`, `msg`, and `formatted_msg` fields by decoding
         the encoded `encoded_logtype and `encoded_variables`.
@@ -148,7 +154,7 @@ def __init__(self, timestamp_format: Optional[str], chunk_size: int) -> None:
         self.metadata: Optional[Metadata] = None
         self.last_timestamp_ms: int
         self.timestamp_format: Optional[str] = timestamp_format
-        self.timezone: Optional[tzinfo]
+        self.timezone: Optional[ZoneInfo]
         self.pos: int
 
     def read_preamble(self) -> int:
@@ -186,7 +192,7 @@ def read_preamble(self) -> int:
             # We do not use the timestamp pattern from the preamble as it may
             # be from other languages and therefore incompatible.
             # self.timestamp_format = self.metadata[METADATA_TIMESTAMP_PATTERN_KEY]
-            self.timezone = dateutil.tz.gettz(self.metadata[METADATA_TZ_ID_KEY])
+            self.timezone = ZoneInfo(self.metadata[METADATA_TZ_ID_KEY])
         return self.pos
 
     @abstractmethod