feat(P4-003): @mosaic/log — log ingest, parsing, tiered storage

Implement AgentLogsRepo with structured log ingest (single + batch),
flexible query builder (filter by session, level, category, tier,
date range), and tiered storage management (hot→warm→cold→purge).
Add getLogsForSummarization() for the summarization pipeline.
Wire LogModule into gateway with REST endpoints at /api/logs.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

packages/log/package.json

@@ -1,6 +1,7 @@
 {
   "name": "@mosaic/log",
   "version": "0.0.0",
+  "type": "module",
   "main": "dist/index.js",
   "types": "dist/index.d.ts",
   "exports": {
@@ -15,6 +16,10 @@
     "typecheck": "tsc --noEmit",
     "test": "vitest run --passWithNoTests"
   },
+  "dependencies": {
+    "@mosaic/db": "workspace:*",
+    "drizzle-orm": "^0.45.1"
+  },
   "devDependencies": {
     "typescript": "^5.8.0",
     "vitest": "^2.0.0"

packages/log/src/agent-logs.ts

@@ -0,0 +1,117 @@
+import { eq, and, desc, lt, sql, type Db, agentLogs } from '@mosaic/db';
+
+export type AgentLog = typeof agentLogs.$inferSelect;
+export type NewAgentLog = typeof agentLogs.$inferInsert;
+
+export type LogLevel = 'debug' | 'info' | 'warn' | 'error';
+export type LogCategory = 'decision' | 'tool_use' | 'learning' | 'error' | 'general';
+export type LogTier = 'hot' | 'warm' | 'cold';
+
+export interface LogQuery {
+  userId?: string;
+  sessionId?: string;
+  level?: LogLevel;
+  category?: LogCategory;
+  tier?: LogTier;
+  since?: Date;
+  until?: Date;
+  limit?: number;
+  offset?: number;
+}
+
+export function createAgentLogsRepo(db: Db) {
+  return {
+    async ingest(entry: NewAgentLog): Promise<AgentLog> {
+      const rows = await db.insert(agentLogs).values(entry).returning();
+      return rows[0]!;
+    },
+
+    async ingestBatch(entries: NewAgentLog[]): Promise<AgentLog[]> {
+      if (entries.length === 0) return [];
+      return db.insert(agentLogs).values(entries).returning();
+    },
+
+    async query(params: LogQuery): Promise<AgentLog[]> {
+      const conditions = [];
+
+      if (params.userId) conditions.push(eq(agentLogs.userId, params.userId));
+      if (params.sessionId) conditions.push(eq(agentLogs.sessionId, params.sessionId));
+      if (params.level) conditions.push(eq(agentLogs.level, params.level));
+      if (params.category) conditions.push(eq(agentLogs.category, params.category));
+      if (params.tier) conditions.push(eq(agentLogs.tier, params.tier));
+      if (params.since) conditions.push(sql`${agentLogs.createdAt} >= ${params.since}`);
+      if (params.until) conditions.push(sql`${agentLogs.createdAt} <= ${params.until}`);
+
+      const where = conditions.length > 0 ? and(...conditions) : undefined;
+
+      return db
+        .select()
+        .from(agentLogs)
+        .where(where)
+        .orderBy(desc(agentLogs.createdAt))
+        .limit(params.limit ?? 100)
+        .offset(params.offset ?? 0);
+    },
+
+    async findById(id: string): Promise<AgentLog | undefined> {
+      const rows = await db.select().from(agentLogs).where(eq(agentLogs.id, id));
+      return rows[0];
+    },
+
+    /**
+     * Transition hot logs older than the cutoff to warm tier.
+     * Returns the number of logs transitioned.
+     */
+    async promoteToWarm(olderThan: Date): Promise<number> {
+      const result = await db
+        .update(agentLogs)
+        .set({ tier: 'warm', summarizedAt: new Date() })
+        .where(and(eq(agentLogs.tier, 'hot'), lt(agentLogs.createdAt, olderThan)))
+        .returning();
+      return result.length;
+    },
+
+    /**
+     * Transition warm logs older than the cutoff to cold tier.
+     */
+    async promoteToCold(olderThan: Date): Promise<number> {
+      const result = await db
+        .update(agentLogs)
+        .set({ tier: 'cold', archivedAt: new Date() })
+        .where(and(eq(agentLogs.tier, 'warm'), lt(agentLogs.createdAt, olderThan)))
+        .returning();
+      return result.length;
+    },
+
+    /**
+     * Delete cold logs older than the retention period.
+     */
+    async purge(olderThan: Date): Promise<number> {
+      const result = await db
+        .delete(agentLogs)
+        .where(and(eq(agentLogs.tier, 'cold'), lt(agentLogs.createdAt, olderThan)))
+        .returning();
+      return result.length;
+    },
+
+    /**
+     * Get hot logs ready for summarization (decisions + learnings).
+     */
+    async getLogsForSummarization(olderThan: Date, limit = 100): Promise<AgentLog[]> {
+      return db
+        .select()
+        .from(agentLogs)
+        .where(
+          and(
+            eq(agentLogs.tier, 'hot'),
+            lt(agentLogs.createdAt, olderThan),
+            sql`${agentLogs.category} IN ('decision', 'learning', 'tool_use')`,
+          ),
+        )
+        .orderBy(agentLogs.createdAt)
+        .limit(limit);
+    },
+  };
+}
+
+export type AgentLogsRepo = ReturnType<typeof createAgentLogsRepo>;

packages/log/src/index.ts

@@ -1 +1,11 @@
-export const VERSION = '0.0.0';
+export { createLogService, type LogService } from './log-service.js';
+export {
+  createAgentLogsRepo,
+  type AgentLogsRepo,
+  type AgentLog,
+  type NewAgentLog,
+  type LogLevel,
+  type LogCategory,
+  type LogTier,
+  type LogQuery,
+} from './agent-logs.js';

packages/log/src/log-service.ts

@@ -0,0 +1,12 @@
+import type { Db } from '@mosaic/db';
+import { createAgentLogsRepo, type AgentLogsRepo } from './agent-logs.js';
+
+export interface LogService {
+  logs: AgentLogsRepo;
+}
+
+export function createLogService(db: Db): LogService {
+  return {
+    logs: createAgentLogsRepo(db),
+  };
+}