Keep each walk's phases and say a delivery over its budget (hq ADR 0282 slice 1, issue 382)

The operator's budget (a leaf module running everywhere within five minutes
of its merge, a core module within ten) cannot be held to without knowing
where a walk's time goes. A walk now keeps when its batch's window closed,
when it was cut and its class (migration 0093), each gate reading, and what
each machine of the rest was sent; 'delivery walks' and plan-moved say its
phases from the merge to every machine of the rest reporting the build
applied, and ended walks keep them as walk-phase durations per class. Probe
D16 reads mesh-delivery's 'times' and raises delivery.<class>.over-budget.
A phase that cannot be measured is said unknown, never zero. Measurement
only: no walk is held, sent or judged differently.

internal/inventory/durations.go

@@ -17,10 +17,13 @@ const (
 	DurationHeartbeatGap = "heartbeat-gap"
 	DurationPlanTier     = "plan-tier"
 	DurationBuild        = "build"
+	// DurationWalkPhase is one phase of an ended walk, per class (novox/hq ADR 0282 decision 6): subject
+	// "<class>/<phase>", and "<class>/total" for its merge to every machine running it.
+	DurationWalkPhase = "walk-phase"
 )
 
 // DurationKinds are every kind, in the order `durations` shows them.
-var DurationKinds = []string{DurationApply, DurationHeartbeatGap, DurationPlanTier, DurationBuild}
+var DurationKinds = []string{DurationApply, DurationHeartbeatGap, DurationPlanTier, DurationBuild, DurationWalkPhase}
 
 // DurationsKeptFor is how long a duration is kept: long enough to set a bound from, and to correct it
 // in Phase 1's first live week.
@@ -100,6 +103,14 @@ func (i *Inventory) Durations(ctx context.Context, kind string, since time.Time)
 	return out, rows.Err()
 }
 
+// WalkPhasesKept says whether any phase of a walk is kept as a walk-phase duration, and whether its total is.
+func (i *Inventory) WalkPhasesKept(ctx context.Context, plan string) (anyKept, totalKept bool, err error) {
+	err = i.store.Pool().QueryRow(ctx,
+		`select count(*) > 0, count(*) filter (where ref = $2) > 0 from duration where kind = $1 and ref like $3`,
+		DurationWalkPhase, plan+"/total", plan+"/%").Scan(&anyKept, &totalKept)
+	return anyKept, totalKept, err
+}
+
 // ForgetOldDurations removes what is older than DurationsKeptFor, and says how many.
 func (i *Inventory) ForgetOldDurations(ctx context.Context) (int64, error) {
 	tag, err := i.store.Pool().Exec(ctx, `delete from duration where recorded < $1`,