feat(docker): Busiest Containers shows bars of the last hours beside each figure, scaled to the row's peak with a floor (#5214)

The fill bars were a share of the host's capacity, a sliver on hosts with
80 cores. Each figure now sits beside 24 bars of the last 6 hours (1h/24h
per widget), each row scaled to its own peak but never below 1 core or
1 GiB (configurable per widget), so a 0.05-core container reads flat and
a bar's height means real load. One grouped date_bin query feeds them.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

plugins/docker/routes.py

@@ -269,10 +269,16 @@ CPU_AVERAGE_MINUTES = 5
 async def widget_resources():
     """HTMX dashboard widget: the containers using the most CPU, averaged over
     the last few minutes so the order holds still between polls, with their
-    CPU in cores and memory in bytes."""
-    limit = max(1, min(20, int(request.args.get("limit", 10) or 10)))
+    CPU in cores and memory in bytes, each beside bars of the last few hours
+    scaled to the row's own peak (never below a floor, #5214)."""
+    limit = max(1, min(20, _arg_number("limit", 10, int)))
+    hours = max(1, min(24, _arg_number("hours", 6, int)))
+    cpu_floor = max(0.1, _arg_number("cpu_floor", 1.0, float))
+    mem_floor = max(0.1, _arg_number("mem_floor", 1.0, float))
     widget_id = request.args.get("wid", "0")
-    since = datetime.now(timezone.utc) - timedelta(minutes=CPU_AVERAGE_MINUTES)
+    now = datetime.now(timezone.utc)
+    since = now - timedelta(minutes=CPU_AVERAGE_MINUTES)
+    slots, width = docker_svc.bar_slots(now, hours)
 
     async with current_app.db_sessionmaker() as db:
         # Dedup before the limit, else swarm tasks reported by both managers can
@@ -284,28 +290,48 @@ async def widget_resources():
             .where(DockerMetric.scraped_at >= since)
             .group_by(DockerMetric.host_id, DockerMetric.container_name)
         )).all()}
-        hosts = await docker_svc.host_map(db, {c.host_id for c in running})
-        capacity = await docker_svc.host_capacity(db, {c.host_id for c in running})
 
-    def cpu_of(c):
-        v = average.get((c.host_id, c.name))
-        return c.cpu_pct if v is None else float(v)
+        def cpu_of(c):
+            v = average.get((c.host_id, c.name))
+            return c.cpu_pct if v is None else float(v)
+
+        busiest = sorted(running, key=lambda c: (-(cpu_of(c) or 0), c.name))[:limit]
+        history = await docker_svc.recent_usage(
+            db, {(c.host_id, c.name) for c in busiest}, slots[0], width)
+        hosts = await docker_svc.host_map(db, {c.host_id for c in busiest})
+        capacity = await docker_svc.host_capacity(db, {c.host_id for c in busiest})
+
+    def bars(c, i, scale, floor):
+        seen = history.get((c.host_id, c.name), {})
+        values = [None if seen.get(t) is None or seen[t][i] is None else seen[t][i] * scale
+                  for t in slots]
+        return docker_svc.scaled_bars(values, floor)
 
-    busiest = sorted(running, key=lambda c: (-(cpu_of(c) or 0), c.name))[:limit]
     rows_data = [{
         "c": c,
         "label": docker_svc.display_name(c),
         "host_name": hosts[c.host_id].name if c.host_id in hosts else c.host_id,
         "usage": docker_svc.usage(c, *capacity.get(c.host_id, (None, None)), cpu_pct=cpu_of(c)),
+        "cpu_bars": bars(c, 0, 0.01, cpu_floor),            # cpu_pct → cores
+        "mem_bars": bars(c, 1, 1.0, mem_floor * 2**30),     # bytes; floor in GiB
     } for c in busiest]
     return await render_template(
         "docker/widget_resources.html",
         rows=rows_data,
         minutes=CPU_AVERAGE_MINUTES,
+        hours=hours, cpu_floor=cpu_floor, mem_floor=mem_floor * 2**30,
         widget_id=widget_id,
     )
 
 
+def _arg_number(key, default, kind):
+    """A numeric query argument, or `default` when missing or not a number."""
+    try:
+        return kind(request.args.get(key, default))
+    except (TypeError, ValueError):
+        return default
+
+
 @docker_bp.get("/host/<host_id>")
 @require_role(UserRole.viewer)
 async def host_panel(host_id: str):