Add fleet and per-host concurrency controls

src/lib/server/hosts/index.ts

@@ -533,9 +533,18 @@ export function pendingHostOperationRows(hostId: string, lane: OperationLane = '
             // sibling's work, but still recovers a lost receipt or agent restart.
             .all(hostId, Number(host.readiness === 'ready' || host.mode === 'draining'), Number(host.inventory.capabilities?.includes('instance.cancel-create') ?? false),
                 ...(lane === 'health' ? [new Date(Date.now() - 30_000).toISOString()] : [])) as OperationDeliveryRow[];
+        const preparationLimit = fleetSettings().preparationConcurrency;
+        const preparing = new Set((database().prepare(`SELECT DISTINCT host_id FROM ec_host_operations
+            WHERE kind IN ('library.download','library.import') AND last_delivered_at IS NOT NULL
+            AND state IN ('pending','accepted','running','unknown')`).all() as { host_id: string }[]).map(row => row.host_id));
+        const admitted = rows.filter(operation => {
+            if (!['library.download','library.import'].includes(operation.kind) || preparing.has(hostId) || !preparationLimit) return true;
+            if (preparing.size >= preparationLimit) return false;
+            preparing.add(hostId); return true;
+        });
         const deliveredAt = now();
-        for (const operation of rows) database().prepare('UPDATE ec_host_operations SET last_delivered_at=? WHERE id=?').run(deliveredAt, operation.id);
-        return rows;
+        for (const operation of admitted) database().prepare('UPDATE ec_host_operations SET last_delivered_at=? WHERE id=?').run(deliveredAt, operation.id);
+        return admitted;
     })();
 }
 /** Payloads never change after enqueueing; fetch one delivery's UTF-8 bytes without decoding. */

src/lib/server/hosts/preparation.ts

@@ -8,7 +8,7 @@ import { scheduleAvailabilityRefresh } from './availability.js';
 
 const activeStates = ['pending', 'accepted', 'running', 'unknown'];
 const supersededDownload = 'Superseded by newer game files before delivery to the host.';
-type PreparationOperation = { id: string; sequence: number; state: HostOperationState; updated_at: string; error: string | null };
+type PreparationOperation = { id: string; sequence: number; last_delivered_at: string | null; state: HostOperationState; updated_at: string; error: string | null };
 type Target = { item: HostPreparationItem; image?: string; versionId?: string; requiredBytes: number; operation?: PreparationOperation };
 type QueuedSelection = { libraryId: string; image: string | null };
 type LibraryTarget = Pick<ReturnType<typeof latestPublishedLibraries>[number], 'id' | 'sizeBytes' | 'manifestSha256'> & { name: string; queued?: boolean };
@@ -50,7 +50,7 @@ function targetLibraries(selections: QueuedSelection[]): LibraryTarget[] {
 }
 
 function latestOperation(hostId: string, kind: string, field: string, value: string): PreparationOperation | undefined {
-    return db().prepare(`SELECT id,rowid AS sequence,state,updated_at,error FROM ec_host_operations
+    return db().prepare(`SELECT id,rowid AS sequence,last_delivered_at,state,updated_at,error FROM ec_host_operations
         WHERE host_id=? AND kind=? AND json_extract(payload,?)=? ORDER BY created_at DESC,rowid DESC LIMIT 1`)
         .get(hostId, kind, `$.${field}`, value) as PreparationOperation | undefined;
 }
@@ -117,7 +117,9 @@ function targets(host: Host): Target[] {
         if (blocker) { Object.assign(target.item, blocker); continue; }
         if (operation && activeStates.includes(operation.state)) {
             target.item.state = 'preparing';
-            target.item.detail = operation.state === 'unknown' ? 'Waiting for the agent to reconcile interrupted preparation.'
+            target.item.detail = !target.image && operation.state === 'pending' && !operation.last_delivered_at
+                ? 'Queued for game-file preparation; waiting for agent delivery or fleet preparation capacity.'
+                : operation.state === 'unknown' ? 'Waiting for the agent to reconcile interrupted preparation.'
                 : target.image ? 'Downloading the runtime automatically.'
                 : target.item.cache?.status === 'verifying' ? 'Download complete. Verifying all game files.' : 'Downloading game files. Verification starts after all files arrive.';
         } else if (operation && Date.parse(host.lastHeartbeat!) <= Date.parse(operation.updated_at)) {