DAS-2431: Adds default start/end times for temporal subsetting. (#51)

Author: flamingbear

CHANGELOG.md

@@ -1,12 +1,25 @@
+## [v1.1.14] - 2025-10-22
+
+### Fixed
+
+- Adds support for temporal requests with only start or end time specified.
+  When a Harmony message omits the start time, HOSS now defaults to
+  `0001-01-01T00:00:00.000Z`. When the end time is omitted, HOSS defaults to
+  the current time. This allows temporal subsetting to work with
+  partially-specified time ranges.  These changes do not affect requests
+  without a temporal component or fully qualified temporal requests.
+
 ## [v1.1.13] - 2025-10-21
 
 ### Changed
 
 - Updates evaluation of bbox or polygon constraint to exclude areas outside the
-  projected target grid. An error exception occurs if spatial constraint is entirely
+  projected target grid. An error exception occurs if spatial constraint is
+  entirely outside the projected grid extents.
 - Updates tests to be less dependent on architecture when comparing floats.
 - Fixes test that modified a source file fixture.
-- Changes infrastructure so that local and Docker runs of the tests produce output in same locations.
+- Changes infrastructure so that local and Docker runs of the tests produce
+  output in same locations.
 - GitHub once again captures the artifacts from the tests and coverage.
 
 

docker/service_version.txt

@@ -1 +1 @@
-1.1.13
+1.1.14

hoss/temporal.py

@@ -11,6 +11,7 @@
 from datetime import datetime, timedelta, timezone
 from typing import List, Set
 
+from dateutil import tz
 from dateutil.parser import parse as parse_datetime
 from harmony_service_lib.message import Message
 from netCDF4 import Dataset
@@ -29,6 +30,14 @@
 units_second = {'second', 'seconds', 'sec', 'secs', 's'}
 
 
+DEFAULT_TIME_START = '0001-01-01T00:00:00.000Z'
+
+
+def default_time_end():
+    """Returns the current UTC time to be used as a default ending time."""
+    return datetime.now(tz=tz.UTC).strftime('%Y-%m-%dT%H:%M:%S.000Z')
+
+
 def get_temporal_index_ranges(
     required_variables: Set[str],
     varinfo: VarInfoFromDmr,
@@ -47,8 +56,12 @@ def get_temporal_index_ranges(
     index_ranges = {}
     temporal_dimensions = varinfo.get_temporal_dimensions(required_variables)
 
-    time_start = get_datetime_with_timezone(harmony_message.temporal.start)
-    time_end = get_datetime_with_timezone(harmony_message.temporal.end)
+    time_start = get_datetime_with_timezone(
+        harmony_message.temporal.start or DEFAULT_TIME_START
+    )
+    time_end = get_datetime_with_timezone(
+        harmony_message.temporal.end or default_time_end()
+    )
 
     with Dataset(dimensions_path, 'r') as dimensions_file:
         for dimension in temporal_dimensions:

tests/pip_test_requirements.txt

@@ -3,3 +3,4 @@ pylint ~= 3.3.9
 pytest ~= 8.3.3
 pytest-mock == 3.14.0
 pytest-cov == 7.0.0
+freezegun ~= 1.5.5

tests/unit/test_temporal.py

@@ -1,17 +1,21 @@
 from datetime import datetime, timedelta, timezone
+from gc import freeze
 from shutil import rmtree
 from tempfile import mkdtemp
 from unittest import TestCase
 from unittest.mock import ANY, patch
 
 import numpy as np
+from freezegun import freeze_time
 from harmony_service_lib.message import Message
 from netCDF4 import Dataset
 from numpy.testing import assert_array_equal
 from varinfo import VarInfoFromDmr
 
 from hoss.exceptions import UnsupportedTemporalUnits
 from hoss.temporal import (
+    DEFAULT_TIME_START,
+    default_time_end,
     get_datetime_with_timezone,
     get_temporal_index_ranges,
     get_time_ref,
@@ -130,6 +134,7 @@ def test_get_time_ref(self):
             with self.assertRaises(UnsupportedTemporalUnits):
                 get_time_ref('fortnights since 2021-12-08 00:30:00')
 
+    @freeze_time("2025-10-21 16:15:00 UTC")
     def test_get_datetime_with_timezone(self):
         """Ensure the string is parsed to datetime with timezone."""
         expected_datetime = datetime(2021, 12, 8, 0, 30, tzinfo=timezone.utc)
@@ -153,3 +158,21 @@ def test_get_datetime_with_timezone(self):
             self.assertEqual(
                 get_datetime_with_timezone('2021-12-08 00:30:00Z'), expected_datetime
             )
+
+        with self.subTest('ISO with fractional seconds Z'):
+            self.assertEqual(
+                get_datetime_with_timezone('2021-12-08T00:30:00.000Z'),
+                expected_datetime,
+            )
+
+        with self.subTest('DEFAULT_TIME_START'):
+            expected_start_time = datetime(1, 1, 1, 0, 0, tzinfo=timezone.utc)
+            self.assertEqual(
+                get_datetime_with_timezone(DEFAULT_TIME_START), expected_start_time
+            )
+
+        with self.subTest('default_end_time()'):
+            expected_stop_time = datetime(2025, 10, 21, 16, 15, tzinfo=timezone.utc)
+            self.assertEqual(
+                get_datetime_with_timezone(default_time_end()), expected_stop_time
+            )