structure saas with tools

.venv/lib/python3.10/site-packages/tzlocal/utils.py

@@ -0,0 +1,108 @@
+import calendar
+import datetime
+import logging
+import os
+import time
+import warnings
+import zoneinfo
+
+from tzlocal import windows_tz
+
+log = logging.getLogger("tzlocal")
+
+
+def get_tz_offset(tz):
+    """Get timezone's offset using built-in function datetime.utcoffset()."""
+    return int(datetime.datetime.now(tz).utcoffset().total_seconds())
+
+
+def assert_tz_offset(tz, error=True):
+    """Assert that system's timezone offset equals to the timezone offset found.
+
+    If they don't match, we probably have a misconfiguration, for example, an
+    incorrect timezone set in /etc/timezone file in systemd distributions.
+
+    If error is True, this method will raise a ValueError, otherwise it will
+    emit a warning.
+    """
+
+    tz_offset = get_tz_offset(tz)
+    system_offset = calendar.timegm(time.localtime()) - calendar.timegm(time.gmtime())
+    # No one has timezone offsets less than a minute, so this should be close enough:
+    if abs(tz_offset - system_offset) > 60:
+        msg = (
+            f"Timezone offset does not match system offset: {tz_offset} != {system_offset}. "
+            "Please, check your config files."
+        )
+        if error:
+            raise ValueError(msg)
+        warnings.warn(msg)
+
+
+def _tz_name_from_env(tzenv=None):
+    if tzenv is None:
+        tzenv = os.environ.get("TZ")
+
+    if not tzenv:
+        return None
+
+    log.debug(f"Found a TZ environment: {tzenv}")
+
+    if tzenv[0] == ":":
+        tzenv = tzenv[1:]
+
+    if tzenv in windows_tz.tz_win:
+        # Yup, it's a timezone
+        return tzenv
+
+    if os.path.isabs(tzenv) and os.path.exists(tzenv):
+        # It's a file specification, expand it, if possible
+        parts = os.path.realpath(tzenv).split(os.sep)
+
+        # Is it a zone info zone?
+        possible_tz = "/".join(parts[-2:])
+        if possible_tz in windows_tz.tz_win:
+            # Yup, it is
+            return possible_tz
+
+        # Maybe it's a short one, like UTC?
+        if parts[-1] in windows_tz.tz_win:
+            # Indeed
+            return parts[-1]
+
+    log.debug("TZ does not contain a time zone name")
+    return None
+
+
+def _tz_from_env(tzenv=None):
+    if tzenv is None:
+        tzenv = os.environ.get("TZ")
+
+    if not tzenv:
+        return None
+
+    # Some weird format that exists:
+    if tzenv[0] == ":":
+        tzenv = tzenv[1:]
+
+    # TZ specifies a file
+    if os.path.isabs(tzenv) and os.path.exists(tzenv):
+        # Try to see if we can figure out the name
+        tzname = _tz_name_from_env(tzenv)
+        if not tzname:
+            # Nope, not a standard timezone name, just take the filename
+            tzname = tzenv.split(os.sep)[-1]
+        with open(tzenv, "rb") as tzfile:
+            return zoneinfo.ZoneInfo.from_file(tzfile, key=tzname)
+
+    # TZ must specify a zoneinfo zone.
+    try:
+        tz = zoneinfo.ZoneInfo(tzenv)
+        # That worked, so we return this:
+        return tz
+    except zoneinfo.ZoneInfoNotFoundError:
+        # Nope, it's something like "PST4DST" etc, we can't handle that.
+        raise zoneinfo.ZoneInfoNotFoundError(
+            f"tzlocal() does not support non-zoneinfo timezones like {tzenv}. \n"
+            "Please use a timezone in the form of Continent/City"
+        ) from None