feat: als and prisma

core/als/request-context.middleware.ts

@@ -0,0 +1,19 @@
+import { Injectable, NestMiddleware } from '@nestjs/common';
+import { Request, Response, NextFunction } from 'express';
+import { randomUUID } from 'crypto';
+import { RequestContextService } from './request-context.service';
+
+@Injectable()
+export class RequestContextMiddleware implements NestMiddleware {
+  constructor(private readonly ctx: RequestContextService) {}
+
+  use(req: Request, _: Response, next: NextFunction) {
+    const context = {
+      requestId: randomUUID(),
+      correlationId: (req.headers['x-correlation-id'] as string) ?? undefined,
+      headers: req.headers as Record<string, string>,
+    };
+
+    this.ctx.run(context, next);
+  }
+}

core/als/request-context.module.ts

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+import { Module } from '@nestjs/common';
+import { RequestContextService } from './request-context.service';
+
+@Module({
+  providers: [RequestContextService],
+  exports: [RequestContextService],
+})
+export class RequestContextModule {}

core/als/request-context.service.ts

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+import { Injectable } from '@nestjs/common';
+import { AsyncLocalStorage } from 'async_hooks';
+import { RequestContext } from './request-context.type';
+
+@Injectable()
+/**
+ * RequestContext holds per-request metadata including:
+ * - HTTP request
+ * - Auth payload (decoded JWT, optional)
+ * - Prisma transaction client (optional)
+ * - Correlation ID and other future cross-cutting concerns
+ */
+export class RequestContextService {
+  private readonly als = new AsyncLocalStorage<RequestContext>();
+
+  run(context: RequestContext, fn: () => void) {
+    this.als.run(context, fn);
+  }
+
+  get(): RequestContext {
+    const store = this.als.getStore();
+    if (!store) {
+      throw new Error('RequestContext not initialized');
+    }
+    return store;
+  }
+
+  set<K extends keyof RequestContext>(key: K, value: RequestContext[K]) {
+    this.get()[key] = value;
+  }
+
+  // Helpers
+  get user() {
+    return this.get().user;
+  }
+
+  get tx() {
+    return this.get().tx;
+  }
+
+  set tx(tx) {
+    this.set('tx', tx);
+  }
+
+  get isTransaction(): boolean {
+    return !!this.get().tx;
+  }
+}

core/als/request-context.type.ts

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+import { Prisma } from 'prisma/generated/prisma/client';
+import { AuthPayload } from 'src/auth/types';
+
+export interface RequestContext {
+  requestId: string;
+  correlationId?: string;
+  headers: Record<string, string>;
+  user?: AuthPayload;
+  tx?: Prisma.TransactionClient;
+}