Merge pull request #470 from lsst-sqre/tickets/DM-48682-dates

Add date and age fields to RSPTag

controller/src/controller/models/domain/rspimage.py

@@ -133,6 +133,9 @@ def resolve_alias(self, target: RSPImage) -> None:
                 self.aliases.add(alias)
         target.aliases.add(self.tag)
         self.cycle = target.cycle
+        # If we don't have a date, adopt the target's (which might be None too)
+        if self.date is None:
+            self.date = target.date
 
         # If the tag display name has cycle information, we don't want to keep
         # that part when adding the description of the target tag since it

controller/src/controller/models/domain/rsptag.py

@@ -5,6 +5,7 @@
 from collections import defaultdict
 from collections.abc import Iterable, Iterator
 from dataclasses import dataclass
+from datetime import UTC, datetime, timedelta
 from enum import Enum
 from functools import total_ordering
 from typing import Self
@@ -130,6 +131,17 @@ class RSPImageTag:
     display_name: str
     """Human-readable display name."""
 
+    date: datetime | None
+    """When the image was created, or as close as we can get to that.
+
+    We try to derive this from the tag string: For RSP daily or weekly
+    tags (or experimentals in one of those formats), we can calculate
+    this to within a day or a week, which is good enough for display
+    purposes.  Otherwise, we may be able to extract this info from
+    the registry, but even if we can, it may be image upload time
+    rather than creation time.
+    """
+
     @classmethod
     def alias(cls, tag: str) -> Self:
         """Create an alias tag.
@@ -157,6 +169,7 @@ def alias(cls, tag: str) -> Self:
             version=None,
             cycle=cycle,
             display_name=display_name,
+            date=None,
         )
 
     @classmethod
@@ -192,6 +205,7 @@ def from_str(cls, tag: str) -> Self:
             tag=tag,
             cycle=None,
             display_name=tag,
+            date=None,
         )
 
     def __eq__(self, other: object) -> bool:
@@ -241,6 +255,7 @@ def _from_match(
                 tag=tag,
                 cycle=int(cycle) if cycle else None,
                 display_name=display_name,
+                date=None,
             )
 
         # Experimental tags are often exp_<legal-tag>, meaning that they are
@@ -264,6 +279,7 @@ def _from_match(
                 tag=tag,
                 cycle=subtag.cycle,
                 display_name=display_name,
+                date=subtag.date,
             )
 
         # Determine the build number, the last component of the semantic
@@ -312,6 +328,7 @@ def _from_match(
             tag=tag,
             cycle=int(cycle) if cycle else None,
             display_name=display_name,
+            date=cls._calculate_date(data),
         )
 
     @classmethod
@@ -349,6 +366,48 @@ def _determine_build(
         else:
             return rest if rest else None
 
+    @staticmethod
+    def _calculate_date(tagdata: dict[str, str]) -> datetime | None:
+        """Calculate the date when the image should have been created.
+
+        Parameters
+        ----------
+        tagdata
+            The match groups from the regular expression tag match.
+
+        Returns
+        -------
+        datetime.datetime | None
+            The image creation date if it can be gleaned from the tag.
+        """
+        year = tagdata.get("year")
+        if not year:
+            return None
+        week = tagdata.get("week")
+        if year and week:
+            thursday = 4  # We build on Thursday, which is ISO day 4
+            stamp = datetime.fromisocalendar(int(year), int(week), thursday)
+            return stamp.replace(tzinfo=UTC)
+        month = tagdata.get("month")
+        day = tagdata.get("day")
+        if not (month and day):
+            return None
+        return datetime(int(year), int(month), int(day), tzinfo=UTC)
+
+    def age(self, since: datetime | None = None) -> timedelta | None:
+        """Calculate image age, if possible.
+
+        Parameters
+        ----------
+        since
+            Datestamp to measure age from.  If unspecified, the present.
+        """
+        if self.date is None:
+            return None
+        if since is None:
+            since = datetime.now(tz=UTC)
+        return since - self.date
+
     def _compare(self, other: object) -> int:
         """Compare to image tags for sorting purposes.
 

controller/tests/models/domain/rspimage_test.py

@@ -4,6 +4,7 @@
 
 import os
 from dataclasses import asdict
+from datetime import UTC, datetime
 from random import SystemRandom
 from typing import cast
 
@@ -38,6 +39,7 @@ def test_image() -> None:
         "display_name": "Daily 2077_10_23",
         "version": VersionInfo(2077, 10, 23),
         "cycle": None,
+        "date": datetime(2077, 10, 23, tzinfo=UTC),
         "registry": "lighthouse.ceres",
         "repository": "library/sketchbook",
         "digest": "sha256:1234",
@@ -64,6 +66,7 @@ def test_resolve_alias() -> None:
         digest="sha256:1234",
     )
     assert image.cycle == 45
+    assert image.date == datetime(2077, 10, 23, tzinfo=UTC)
     recommended = RSPImage.from_tag(
         registry="lighthouse.ceres",
         repository="library/sketchbook",
@@ -80,6 +83,7 @@ def test_resolve_alias() -> None:
     assert recommended.display_name == "recommended"
     assert recommended.alias_target is None
     assert recommended.cycle is None
+    assert recommended.date is None
     assert recommended.is_possible_alias
 
     recommended.resolve_alias(image)
@@ -90,6 +94,7 @@ def test_resolve_alias() -> None:
         "Recommended (Daily 2077_10_23, SAL Cycle 0045, Build 003)"
     )
     assert recommended.cycle == 45
+    assert recommended.date == datetime(2077, 10, 23, tzinfo=UTC)
     assert recommended.is_possible_alias
 
     # Can do the same thing with a tag that's already an alias.
@@ -101,6 +106,7 @@ def test_resolve_alias() -> None:
     )
     assert latest_daily.image_type == RSPImageType.ALIAS
     assert latest_daily.display_name == "Latest Daily (SAL Cycle 0045)"
+    assert latest_daily.date is None
 
     latest_daily.resolve_alias(image)
     assert latest_daily.image_type == RSPImageType.ALIAS
@@ -110,6 +116,7 @@ def test_resolve_alias() -> None:
     assert latest_daily.display_name == (
         "Latest Daily (Daily 2077_10_23, SAL Cycle 0045, Build 003)"
     )
+    assert latest_daily.date == datetime(2077, 10, 23, tzinfo=UTC)
 
     # Can't resolve some other image type.
     with pytest.raises(ValueError, match=r"Can only resolve.*"):