ENH: Support timedata as list of dates

src/fmu/dataio/_utils.py

@@ -8,6 +8,7 @@
 import os
 import shlex
 import uuid
+from datetime import datetime
 from io import BufferedIOBase, BytesIO
 from pathlib import Path
 from tempfile import NamedTemporaryFile
@@ -395,3 +396,8 @@ def _load_config_from_path(config_path: Path) -> dict[str, Any]:
         raise FileNotFoundError(f"Cannot find file for global config: {config_path}")
 
     return ut.yaml_load(config_path)
+
+
+def convert_datestr_to_isoformat(value: str, format: str = "%Y%m%d") -> str:
+    """Convert a date string to ISO formatted string"""
+    return datetime.strptime(value, format).isoformat()

src/fmu/dataio/dataio.py

@@ -304,9 +304,11 @@ class ExportData:
 
         tagname: This is a short tag description which be be a part of file name.
 
-        timedata: If given, a list of lists with dates, .e.g.
-            [[20200101, "monitor"], [20180101, "base"]] or just [[2021010]]. The output
-            to metadata will from version 0.9 be different (API change)
+        timedata: Optional. List of dates, where the dates are strings on form
+            'YYYYMMDD', example ['20200101']. A maximum of two dates can be input,
+            the oldest date will be set as t0 in the metadata and the latest date will
+            be t1. Note it is also possible to provide a label to each date by using
+            a list of lists, .e.g. [[20200101, "monitor"], [20180101, "base"]].
 
         vertical_domain: Optional. String with vertical domain either "time" or "depth"
             (default). It is also possible to provide a reference for the vertical
@@ -317,29 +319,6 @@ class ExportData:
 
         undef_is_zero: Flags that nans should be considered as zero in aggregations
 
-
-    .. note:: Comment on time formats
-
-        If two dates are present (i.e. the element represents a difference, the input
-        time format is on the form::
-
-            timedata: [[20200101, "monitor"], [20180101, "base"]]
-
-        Hence the last data (monitor) usually comes first.
-
-        In the new version this will shown in metadata files as where the oldest date is
-        shown as t0::
-
-            data:
-              t0:
-                value: 2018010T00:00:00
-                description: base
-              t1:
-                value: 202020101T00:00:00
-                description: monitor
-
-        The output files will be on the form: somename--t1_t0.ext
-
     """
 
     # ----------------------------------------------------------------------------------
@@ -400,7 +379,7 @@ class ExportData:
     runpath: Optional[Union[str, Path]] = None
     subfolder: str = ""
     tagname: str = ""
-    timedata: Optional[List[list]] = None
+    timedata: Optional[Union[List[str], List[List[str]]]] = None
     unit: Optional[str] = ""
     verbosity: str = "DEPRECATED"  # remove in version 2
     vertical_domain: Union[str, dict] = "depth"  # dict input is deprecated

src/fmu/dataio/providers/objectdata/_base.py

@@ -208,16 +208,21 @@ def _get_stratigraphy_element(self) -> StratigraphyElement:
 
         return StratigraphyElement(name=name)
 
-    def _get_fmu_time_object(self, timedata_item: list[str]) -> Timestamp:
+    def _get_fmu_time_object(self, timedata_item: str | list[str]) -> Timestamp:
         """
-        Returns a Timestamp from a timedata item on list
-        format: ["20200101", "monitor"] where the first item is a date and
+        Returns a Timestamp from a timedata item on either string or
+        list format: ["20200101", "monitor"] where the first item is a date and
         the last item is an optional label
         """
-        value, *label = timedata_item
+
+        if isinstance(timedata_item, list):
+            value, *label = timedata_item
+            return Timestamp(
+                value=datetime.strptime(str(value), "%Y%m%d"),
+                label=label[0] if label else None,
+            )
         return Timestamp(
-            value=datetime.strptime(str(value), "%Y%m%d"),
-            label=label[0] if label else None,
+            value=datetime.strptime(str(timedata_item), "%Y%m%d"),
         )
 
     def _get_timedata(self) -> Time | None:
@@ -234,6 +239,9 @@ def _get_timedata(self) -> Time | None:
         if not self.dataio.timedata:
             return None
 
+        if not isinstance(self.dataio.timedata, list):
+            raise ValueError("The 'timedata' argument should be a list")
+
         if len(self.dataio.timedata) > 2:
             raise ValueError("The 'timedata' argument can maximum contain two dates")
 

tests/test_units/test_dataio.py

@@ -12,7 +12,7 @@
 import yaml
 
 from fmu.dataio._model.enums import FMUContext
-from fmu.dataio._utils import prettyprint_dict
+from fmu.dataio._utils import convert_datestr_to_isoformat, prettyprint_dict
 from fmu.dataio.dataio import ExportData, read_metadata
 from fmu.dataio.providers._fmu import FmuEnv
 
@@ -1244,3 +1244,96 @@ def test_top_base_as_strings_from_config(globalconfig1, regsurf):
     meta = edata.generate_metadata(regsurf)
     assert meta["data"]["top"]["name"] == "TheTopHorizon"
     assert meta["data"]["base"]["name"] == "TheBaseHorizon"
+
+
+def test_timedata_single_date(globalconfig1, regsurf):
+    """Test that entering a single date works"""
+
+    t0 = "20230101"
+
+    meta = ExportData(
+        config=globalconfig1,
+        content="depth",
+        name="TopWhatever",
+        timedata=[t0],
+    ).generate_metadata(regsurf)
+
+    assert meta["data"]["time"]["t0"]["value"] == convert_datestr_to_isoformat(t0)
+    assert "t1" not in meta["data"]["time"]
+
+    # should also work with the double list syntax
+    meta = ExportData(
+        config=globalconfig1,
+        content="depth",
+        name="TopWhatever",
+        timedata=[[t0]],
+    ).generate_metadata(regsurf)
+
+    assert meta["data"]["time"]["t0"]["value"] == convert_datestr_to_isoformat(t0)
+    assert "t1" not in meta["data"]["time"]
+
+
+def test_timedata_multiple_date(globalconfig1, regsurf):
+    """Test that entering two dates works"""
+
+    t0 = "20230101"
+    t1 = "20240101"
+
+    meta = ExportData(
+        config=globalconfig1,
+        content="depth",
+        name="TopWhatever",
+        timedata=[t0, t1],
+    ).generate_metadata(regsurf)
+
+    assert meta["data"]["time"]["t0"]["value"] == convert_datestr_to_isoformat(t0)
+    assert meta["data"]["time"]["t1"]["value"] == convert_datestr_to_isoformat(t1)
+
+    # should also work with the double list syntax
+    meta = ExportData(
+        config=globalconfig1,
+        content="depth",
+        name="TopWhatever",
+        timedata=[[t0], [t1]],
+    ).generate_metadata(regsurf)
+
+    assert meta["data"]["time"]["t0"]["value"] == convert_datestr_to_isoformat(t0)
+    assert meta["data"]["time"]["t1"]["value"] == convert_datestr_to_isoformat(t1)
+
+
+def test_timedata_multiple_date_sorting(globalconfig1, regsurf):
+    """Test that dates are sorted no matter the input order"""
+
+    t0 = "20230101"
+    t1 = "20240101"
+
+    meta = ExportData(
+        config=globalconfig1,
+        content="depth",
+        name="TopWhatever",
+        timedata=[t1, t0],  # set oldest first
+    ).generate_metadata(regsurf)
+
+    # check that oldest is t0
+    assert meta["data"]["time"]["t0"]["value"] == convert_datestr_to_isoformat(t0)
+    assert meta["data"]["time"]["t1"]["value"] == convert_datestr_to_isoformat(t1)
+
+
+def test_timedata_wrong_format(globalconfig1, regsurf):
+    """Test that error is raised if timedata is input incorrect"""
+
+    with pytest.raises(ValueError, match="should be a list"):
+        ExportData(
+            config=globalconfig1,
+            content="depth",
+            name="TopWhatever",
+            timedata="20230101",
+        ).generate_metadata(regsurf)
+
+    with pytest.raises(ValueError, match="two dates"):
+        ExportData(
+            config=globalconfig1,
+            content="depth",
+            name="TopWhatever",
+            timedata=["20230101", "20240101", "20250101"],
+        ).generate_metadata(regsurf)