Prevent accounting cache refresh stampedes

.env.example

@@ -32,6 +32,14 @@ API_PORT=3334
 API_BIND_HOST=127.0.0.1
 API_PUBLIC_PORT=3334
 API_WORKERS=4
+# Bound abandoned or slow API sockets. These settings apply only to the
+# HTTP(S) listener and do not affect Stratum connections.
+API_CONNECTION_TIMEOUT_MS=15000
+API_KEEP_ALIVE_TIMEOUT_MS=5000
+API_REQUEST_TIMEOUT_MS=15000
+API_HEADERS_TIMEOUT_MS=10000
+API_MAX_REQUESTS_PER_SOCKET=100
+API_MAX_CONNECTIONS_PER_WORKER=500
 
 # Docker json-file log rotation. Applies when using the compose files.
 DOCKER_LOG_MAX_SIZE=100m
@@ -162,6 +170,10 @@ SHARE_ACCOUNTING_FLUSH_INTERVAL_MS=25
 SHARE_ACCOUNTING_MAX_QUEUE_SIZE=50000
 SHARE_ACCOUNTING_SUMMARY_CACHE_MS=2500
 SHARE_ACCOUNTING_SUMMARY_CACHE_MAX=10000
+SHARE_ACCOUNTING_REDIS_SUMMARY_CACHE_MS=300000
+SHARE_ACCOUNTING_REDIS_SUMMARY_STALE_CACHE_MS=3600000
+SHARE_ACCOUNTING_REDIS_SUMMARY_LOCK_MS=30000
+SHARE_ACCOUNTING_REDIS_SUMMARY_LOCK_WAIT_MS=5000
 CLIENT_HASHRATE_PERSIST_INTERVAL_MS=60000
 SHARE_ROLLUP_ENABLED=true
 SHARE_ROLLUP_INTERVAL_MS=60000

docker-compose.external-db.yml

@@ -74,6 +74,12 @@ services:
       API_PORT: ${API_PORT:-3334}
       API_SECURE: ${API_SECURE:-false}
       API_WORKERS: ${API_WORKERS:-4}
+      API_CONNECTION_TIMEOUT_MS: ${API_CONNECTION_TIMEOUT_MS:-15000}
+      API_KEEP_ALIVE_TIMEOUT_MS: ${API_KEEP_ALIVE_TIMEOUT_MS:-5000}
+      API_REQUEST_TIMEOUT_MS: ${API_REQUEST_TIMEOUT_MS:-15000}
+      API_HEADERS_TIMEOUT_MS: ${API_HEADERS_TIMEOUT_MS:-10000}
+      API_MAX_REQUESTS_PER_SOCKET: ${API_MAX_REQUESTS_PER_SOCKET:-100}
+      API_MAX_CONNECTIONS_PER_WORKER: ${API_MAX_CONNECTIONS_PER_WORKER:-500}
       PM2_ENABLED: ${PM2_ENABLED:-true}
       STRATUM_WORKERS: ${STRATUM_WORKERS:-auto}
       STRATUM_PORTS: ${STRATUM_PORTS:-3333,3332,3331,3330}
@@ -100,6 +106,10 @@ services:
       SHARE_ACCOUNTING_MAX_QUEUE_SIZE: ${SHARE_ACCOUNTING_MAX_QUEUE_SIZE:-50000}
       SHARE_ACCOUNTING_SUMMARY_CACHE_MS: ${SHARE_ACCOUNTING_SUMMARY_CACHE_MS:-2500}
       SHARE_ACCOUNTING_SUMMARY_CACHE_MAX: ${SHARE_ACCOUNTING_SUMMARY_CACHE_MAX:-10000}
+      SHARE_ACCOUNTING_REDIS_SUMMARY_CACHE_MS: ${SHARE_ACCOUNTING_REDIS_SUMMARY_CACHE_MS:-300000}
+      SHARE_ACCOUNTING_REDIS_SUMMARY_STALE_CACHE_MS: ${SHARE_ACCOUNTING_REDIS_SUMMARY_STALE_CACHE_MS:-3600000}
+      SHARE_ACCOUNTING_REDIS_SUMMARY_LOCK_MS: ${SHARE_ACCOUNTING_REDIS_SUMMARY_LOCK_MS:-30000}
+      SHARE_ACCOUNTING_REDIS_SUMMARY_LOCK_WAIT_MS: ${SHARE_ACCOUNTING_REDIS_SUMMARY_LOCK_WAIT_MS:-5000}
       SHARE_ROLLUP_ENABLED: ${SHARE_ROLLUP_ENABLED:-true}
       SHARE_ROLLUP_INTERVAL_MS: ${SHARE_ROLLUP_INTERVAL_MS:-60000}
       SHARE_ROLLUP_SAFETY_LAG_SECONDS: ${SHARE_ROLLUP_SAFETY_LAG_SECONDS:-30}

docker-compose.yml

@@ -104,6 +104,16 @@ services:
       API_PORT: ${API_PORT:-3334}
       API_SECURE: ${API_SECURE:-false}
       API_WORKERS: ${API_WORKERS:-4}
+      API_CONNECTION_TIMEOUT_MS: ${API_CONNECTION_TIMEOUT_MS:-15000}
+      API_KEEP_ALIVE_TIMEOUT_MS: ${API_KEEP_ALIVE_TIMEOUT_MS:-5000}
+      API_REQUEST_TIMEOUT_MS: ${API_REQUEST_TIMEOUT_MS:-15000}
+      API_HEADERS_TIMEOUT_MS: ${API_HEADERS_TIMEOUT_MS:-10000}
+      API_MAX_REQUESTS_PER_SOCKET: ${API_MAX_REQUESTS_PER_SOCKET:-100}
+      API_MAX_CONNECTIONS_PER_WORKER: ${API_MAX_CONNECTIONS_PER_WORKER:-500}
+      SHARE_ACCOUNTING_REDIS_SUMMARY_CACHE_MS: ${SHARE_ACCOUNTING_REDIS_SUMMARY_CACHE_MS:-300000}
+      SHARE_ACCOUNTING_REDIS_SUMMARY_STALE_CACHE_MS: ${SHARE_ACCOUNTING_REDIS_SUMMARY_STALE_CACHE_MS:-3600000}
+      SHARE_ACCOUNTING_REDIS_SUMMARY_LOCK_MS: ${SHARE_ACCOUNTING_REDIS_SUMMARY_LOCK_MS:-30000}
+      SHARE_ACCOUNTING_REDIS_SUMMARY_LOCK_WAIT_MS: ${SHARE_ACCOUNTING_REDIS_SUMMARY_LOCK_WAIT_MS:-5000}
       PM2_ENABLED: ${PM2_ENABLED:-true}
       STRATUM_WORKERS: ${STRATUM_WORKERS:-auto}
       STRATUM_PORTS: ${STRATUM_PORTS:-3333,3332,3331,3330}

full-setup/docker-compose-mainnet.yml

@@ -108,6 +108,16 @@ services:
       DB_DATABASE: public_pool_mainnet
       REDIS_URL: redis://redis:6379
       API_WORKERS: ${API_WORKERS:-4}
+      API_CONNECTION_TIMEOUT_MS: ${API_CONNECTION_TIMEOUT_MS:-15000}
+      API_KEEP_ALIVE_TIMEOUT_MS: ${API_KEEP_ALIVE_TIMEOUT_MS:-5000}
+      API_REQUEST_TIMEOUT_MS: ${API_REQUEST_TIMEOUT_MS:-15000}
+      API_HEADERS_TIMEOUT_MS: ${API_HEADERS_TIMEOUT_MS:-10000}
+      API_MAX_REQUESTS_PER_SOCKET: ${API_MAX_REQUESTS_PER_SOCKET:-100}
+      API_MAX_CONNECTIONS_PER_WORKER: ${API_MAX_CONNECTIONS_PER_WORKER:-500}
+      SHARE_ACCOUNTING_REDIS_SUMMARY_CACHE_MS: ${SHARE_ACCOUNTING_REDIS_SUMMARY_CACHE_MS:-300000}
+      SHARE_ACCOUNTING_REDIS_SUMMARY_STALE_CACHE_MS: ${SHARE_ACCOUNTING_REDIS_SUMMARY_STALE_CACHE_MS:-3600000}
+      SHARE_ACCOUNTING_REDIS_SUMMARY_LOCK_MS: ${SHARE_ACCOUNTING_REDIS_SUMMARY_LOCK_MS:-30000}
+      SHARE_ACCOUNTING_REDIS_SUMMARY_LOCK_WAIT_MS: ${SHARE_ACCOUNTING_REDIS_SUMMARY_LOCK_WAIT_MS:-5000}
       PM2_ENABLED: "true"
       STRATUM_WORKERS: ${STRATUM_WORKERS:-2}
       STRATUM_MIN_DIFFICULTY: ${STRATUM_MIN_DIFFICULTY:-1}

src/ORM/share-accounting/share-accounting.service.spec.ts

@@ -365,11 +365,65 @@ describe('ShareAccountingService', () => {
         expect(repository.query).toHaveBeenCalledTimes(1);
         expect(redis.setJsonCache).toHaveBeenCalledWith(
             expect.stringContaining('accounting:summary:'),
-            expect.objectContaining({ totalAcceptedShares: 1 }),
-            30000,
+            expect.objectContaining({
+                schemaVersion: 1,
+                refreshedAtMs: expect.any(Number),
+                value: expect.objectContaining({ totalAcceptedShares: 1 }),
+            }),
+            3600000,
         );
     });
 
+    it('serves a stale shared summary while one API worker refreshes it', async () => {
+        process.env.SHARE_ACCOUNTING_SUMMARY_CACHE_MS = '0';
+        process.env.SHARE_ACCOUNTING_REDIS_SUMMARY_CACHE_MS = '100';
+        const staleSummary = {
+            ...new ShareAccountingService({} as any).emptySummary(),
+            totalAcceptedShares: 7,
+        };
+        const repository = {
+            query: jest.fn().mockResolvedValueOnce([{
+                totalAcceptedShares: '8',
+                totalCreditedDifficulty: '256',
+                acceptedSharesLast10Minutes: '1',
+                creditedDifficultyLast10Minutes: '32',
+                acceptedSharesLastHour: '8',
+                creditedDifficultyLastHour: '256',
+                acceptedSharesLastDay: '8',
+                creditedDifficultyLastDay: '256',
+                hashRateLast10Minutes: '1',
+                hashRateLastHour: '1',
+                latestShareAt: null,
+            }]),
+        };
+        const redis = {
+            getJsonCache: jest.fn().mockResolvedValue({
+                schemaVersion: 1,
+                refreshedAtMs: Date.now() - 1000,
+                value: staleSummary,
+            }),
+            setJsonCache: jest.fn().mockResolvedValue(undefined),
+            tryAcquireJsonCacheLock: jest.fn().mockResolvedValue(true),
+            releaseJsonCacheLock: jest.fn().mockResolvedValue(undefined),
+        };
+        const service = new ShareAccountingService(repository as any, redis as any);
+
+        await expect(service.getAddressSummary('bc1qstale')).resolves.toEqual(staleSummary);
+        await new Promise(resolve => setImmediate(resolve));
+
+        expect(repository.query).toHaveBeenCalledTimes(1);
+        expect(redis.tryAcquireJsonCacheLock).toHaveBeenCalledTimes(1);
+        expect(redis.setJsonCache).toHaveBeenCalledWith(
+            expect.stringContaining('accounting:summary:'),
+            expect.objectContaining({
+                schemaVersion: 1,
+                value: expect.objectContaining({ totalAcceptedShares: 8 }),
+            }),
+            3600000,
+        );
+        expect(redis.releaseJsonCacheLock).toHaveBeenCalledTimes(1);
+    });
+
     it('should refresh pool summaries from completed rollup buckets and current round rollups', async () => {
         const redis = {
             getJsonCache: jest.fn().mockResolvedValue(null),

src/ORM/share-accounting/share-accounting.service.ts

@@ -1,5 +1,6 @@
 import { Injectable, OnModuleDestroy, OnModuleInit } from '@nestjs/common';
 import { InjectRepository } from '@nestjs/typeorm';
+import { randomUUID } from 'crypto';
 import { Repository } from 'typeorm';
 
 import { AcceptedShareEntity } from '../accepted-share/accepted-share.entity';
@@ -88,7 +89,10 @@ const DEFAULT_FLUSH_INTERVAL_MS = 25;
 const DEFAULT_MAX_QUEUE_SIZE = 50000;
 const DEFAULT_SUMMARY_CACHE_MS = 2500;
 const DEFAULT_SUMMARY_CACHE_MAX = 10000;
-const DEFAULT_REDIS_SUMMARY_CACHE_MS = 30000;
+const DEFAULT_REDIS_SUMMARY_CACHE_MS = 5 * 60 * 1000;
+const DEFAULT_REDIS_SUMMARY_STALE_CACHE_MS = 60 * 60 * 1000;
+const DEFAULT_REDIS_SUMMARY_LOCK_MS = 30 * 1000;
+const DEFAULT_REDIS_SUMMARY_LOCK_WAIT_MS = 5 * 1000;
 const DEFAULT_ROLLUP_INTERVAL_MS = 60000;
 const DEFAULT_ROLLUP_SAFETY_LAG_SECONDS = 10;
 const DEFAULT_ROLLUP_MAX_SHARES_PER_BATCH = 5000000;
@@ -103,6 +107,7 @@ export class ShareAccountingService implements OnModuleInit, OnModuleDestroy {
     private activeRollup: Promise<void> | null = null;
     private summaryCache = new Map<string, SummaryCacheEntry>();
     private summaryInFlight = new Map<string, Promise<ShareAccountingSummary>>();
+    private redisSummaryRefreshInFlight = new Map<string, Promise<void>>();
     private readonly poolSummaryCacheKey = 'accounting:pool-summary';
     private readonly batchSize = this.readPositiveInt('SHARE_ACCOUNTING_BATCH_SIZE', DEFAULT_BATCH_SIZE);
     private readonly flushIntervalMs = this.readPositiveInt('SHARE_ACCOUNTING_FLUSH_INTERVAL_MS', DEFAULT_FLUSH_INTERVAL_MS);
@@ -110,6 +115,12 @@ export class ShareAccountingService implements OnModuleInit, OnModuleDestroy {
     private readonly summaryCacheMs = this.readNonNegativeInt('SHARE_ACCOUNTING_SUMMARY_CACHE_MS', DEFAULT_SUMMARY_CACHE_MS);
     private readonly summaryCacheMax = this.readPositiveInt('SHARE_ACCOUNTING_SUMMARY_CACHE_MAX', DEFAULT_SUMMARY_CACHE_MAX);
     private readonly redisSummaryCacheMs = this.readNonNegativeInt('SHARE_ACCOUNTING_REDIS_SUMMARY_CACHE_MS', DEFAULT_REDIS_SUMMARY_CACHE_MS);
+    private readonly redisSummaryStaleCacheMs = Math.max(
+        this.redisSummaryCacheMs,
+        this.readPositiveInt('SHARE_ACCOUNTING_REDIS_SUMMARY_STALE_CACHE_MS', DEFAULT_REDIS_SUMMARY_STALE_CACHE_MS),
+    );
+    private readonly redisSummaryLockMs = this.readPositiveInt('SHARE_ACCOUNTING_REDIS_SUMMARY_LOCK_MS', DEFAULT_REDIS_SUMMARY_LOCK_MS);
+    private readonly redisSummaryLockWaitMs = this.readPositiveInt('SHARE_ACCOUNTING_REDIS_SUMMARY_LOCK_WAIT_MS', DEFAULT_REDIS_SUMMARY_LOCK_WAIT_MS);
     private readonly shareRollupEnabled = this.readBoolean('SHARE_ROLLUP_ENABLED', true);
     private readonly shareRollupIntervalMs = this.readPositiveInt('SHARE_ROLLUP_INTERVAL_MS', DEFAULT_ROLLUP_INTERVAL_MS);
     private readonly shareRollupSafetyLagSeconds = this.readNonNegativeInt('SHARE_ROLLUP_SAFETY_LAG_SECONDS', DEFAULT_ROLLUP_SAFETY_LAG_SECONDS);
@@ -597,25 +608,175 @@ export class ShareAccountingService implements OnModuleInit, OnModuleDestroy {
 
     private async loadCachedSummary(filter: AccountingFilter, cacheKey: string): Promise<ShareAccountingSummary> {
         const redisCacheKey = `accounting:summary:${cacheKey}`;
+        if (this.redisMessagingService == null || this.redisSummaryCacheMs <= 0) {
+            return this.loadSummary(filter);
+        }
+
+        const cached = await this.readRedisSummaryCache(redisCacheKey);
+        if (cached != null) {
+            if (Date.now() - cached.refreshedAtMs >= this.redisSummaryCacheMs) {
+                this.refreshRedisSummaryCacheInBackground(filter, redisCacheKey);
+            }
+            return cached.value;
+        }
+
+        return this.loadColdRedisSummaryCache(filter, redisCacheKey);
+    }
+
+    private async readRedisSummaryCache(redisCacheKey: string): Promise<RedisSummaryCacheEntry | null> {
         const cached = await this.redisMessagingService
-            ?.getJsonCache<ShareAccountingSummary>(redisCacheKey)
+            ?.getJsonCache<RedisSummaryCacheEntry | ShareAccountingSummary>(redisCacheKey)
             .catch(error => {
                 console.error(`Share accounting summary cache read failed: ${error.message}`);
                 return null;
             });
-        if (cached != null) {
+        if (cached == null) {
+            return null;
+        }
+
+        if (this.isRedisSummaryCacheEntry(cached)) {
             return cached;
         }
 
+        // Cache entries written by older workers have no timestamp. Their old
+        // short Redis TTL still bounds how long they can be treated as fresh.
+        return {
+            schemaVersion: 1,
+            refreshedAtMs: Date.now(),
+            value: cached,
+        };
+    }
+
+    private async loadColdRedisSummaryCache(
+        filter: AccountingFilter,
+        redisCacheKey: string,
+    ): Promise<ShareAccountingSummary> {
+        if (!this.supportsRedisSummaryLock()) {
+            const summary = await this.loadSummary(filter);
+            await this.storeRedisSummaryCache(redisCacheKey, summary);
+            return summary;
+        }
+
+        const owner = randomUUID();
+        const acquired = await this.tryAcquireRedisSummaryLock(redisCacheKey, owner);
+        if (acquired === true) {
+            return this.loadAndStoreRedisSummary(filter, redisCacheKey, owner);
+        }
+        if (acquired == null) {
+            const summary = await this.loadSummary(filter);
+            await this.storeRedisSummaryCache(redisCacheKey, summary);
+            return summary;
+        }
+
+        const deadline = Date.now() + this.redisSummaryLockWaitMs;
+        while (Date.now() < deadline) {
+            await new Promise(resolve => setTimeout(resolve, 50));
+            const cached = await this.readRedisSummaryCache(redisCacheKey);
+            if (cached != null) {
+                return cached.value;
+            }
+        }
+
+        // Redis locking is an optimization, not an availability dependency.
+        // If a lock holder died or a refresh exceeded its budget, fail open.
         const summary = await this.loadSummary(filter);
+        await this.storeRedisSummaryCache(redisCacheKey, summary);
+        return summary;
+    }
+
+    private refreshRedisSummaryCacheInBackground(filter: AccountingFilter, redisCacheKey: string): void {
+        if (this.redisSummaryRefreshInFlight.has(redisCacheKey)) {
+            return;
+        }
+
+        const refresh = this.refreshRedisSummaryCache(filter, redisCacheKey)
+            .catch(error => {
+                console.error(`Share accounting summary background refresh failed: ${error.message}`);
+            })
+            .finally(() => {
+                this.redisSummaryRefreshInFlight.delete(redisCacheKey);
+            });
+        this.redisSummaryRefreshInFlight.set(redisCacheKey, refresh);
+    }
+
+    private async refreshRedisSummaryCache(filter: AccountingFilter, redisCacheKey: string): Promise<void> {
+        if (!this.supportsRedisSummaryLock()) {
+            const summary = await this.loadSummary(filter);
+            await this.storeRedisSummaryCache(redisCacheKey, summary);
+            return;
+        }
+
+        const owner = randomUUID();
+        if (await this.tryAcquireRedisSummaryLock(redisCacheKey, owner) !== true) {
+            return;
+        }
+
+        await this.loadAndStoreRedisSummary(filter, redisCacheKey, owner);
+    }
+
+    private async loadAndStoreRedisSummary(
+        filter: AccountingFilter,
+        redisCacheKey: string,
+        owner: string,
+    ): Promise<ShareAccountingSummary> {
+        try {
+            const summary = await this.loadSummary(filter);
+            await this.storeRedisSummaryCache(redisCacheKey, summary);
+            return summary;
+        } finally {
+            if (this.supportsRedisSummaryLock()) {
+                await this.redisMessagingService
+                    .releaseJsonCacheLock(redisCacheKey, owner)
+                    .catch(error => {
+                        console.error(`Share accounting summary cache lock release failed: ${error.message}`);
+                    });
+            }
+        }
+    }
+
+    private async storeRedisSummaryCache(
+        redisCacheKey: string,
+        summary: ShareAccountingSummary,
+    ): Promise<void> {
+        const entry: RedisSummaryCacheEntry = {
+            schemaVersion: 1,
+            refreshedAtMs: Date.now(),
+            value: summary,
+        };
 
         await this.redisMessagingService
-            ?.setJsonCache(redisCacheKey, summary, this.redisSummaryCacheMs)
+            ?.setJsonCache(redisCacheKey, entry, this.redisSummaryStaleCacheMs)
             .catch(error => {
                 console.error(`Share accounting summary cache write failed: ${error.message}`);
             });
+    }
 
-        return summary;
+    private async tryAcquireRedisSummaryLock(redisCacheKey: string, owner: string): Promise<boolean | null> {
+        if (!this.supportsRedisSummaryLock()) {
+            return null;
+        }
+
+        try {
+            return await this.redisMessagingService
+                .tryAcquireJsonCacheLock(redisCacheKey, owner, this.redisSummaryLockMs);
+        } catch (error) {
+            console.error(`Share accounting summary cache lock failed: ${error.message}`);
+            return null;
+        }
+    }
+
+    private supportsRedisSummaryLock(): boolean {
+        return typeof this.redisMessagingService?.tryAcquireJsonCacheLock === 'function'
+            && typeof this.redisMessagingService?.releaseJsonCacheLock === 'function';
+    }
+
+    private isRedisSummaryCacheEntry(
+        cached: RedisSummaryCacheEntry | ShareAccountingSummary,
+    ): cached is RedisSummaryCacheEntry {
+        const candidate = cached as Partial<RedisSummaryCacheEntry>;
+        return candidate.schemaVersion === 1
+            && Number.isFinite(candidate.refreshedAtMs)
+            && candidate.value != null;
     }
 
     private async loadSummary(filter: AccountingFilter): Promise<ShareAccountingSummary> {
@@ -924,3 +1085,9 @@ interface SummaryCacheEntry {
     expiresAt: number;
     value: ShareAccountingSummary;
 }
+
+interface RedisSummaryCacheEntry {
+    schemaVersion: 1;
+    refreshedAtMs: number;
+    value: ShareAccountingSummary;
+}

src/main.ts

@@ -10,6 +10,18 @@ import * as ecc from 'tiny-secp256k1';
 import { ApiModule } from './api.module';
 import { AppModule } from './app.module';
 
+const DEFAULT_API_CONNECTION_TIMEOUT_MS = 15_000;
+const DEFAULT_API_KEEP_ALIVE_TIMEOUT_MS = 5_000;
+const DEFAULT_API_REQUEST_TIMEOUT_MS = 15_000;
+const DEFAULT_API_HEADERS_TIMEOUT_MS = 10_000;
+const DEFAULT_API_MAX_REQUESTS_PER_SOCKET = 100;
+const DEFAULT_API_MAX_CONNECTIONS_PER_WORKER = 500;
+
+function readPositiveInt(name: string, fallback: number): number {
+  const value = Number(process.env[name]);
+  return Number.isInteger(value) && value > 0 ? value : fallback;
+}
+
 async function bootstrap() {
   if (process.env.API_PORT == null) {
     console.error('It appears your environment is not configured, create and populate an .env file.');
@@ -23,13 +35,18 @@ async function bootstrap() {
   const keyPath = path.join(currentDirectory, 'secrets', 'key.pem');
   const certPath = path.join(currentDirectory, 'secrets', 'cert.pem');
 
-  let options: any = {};
+  let options: any = serveApi
+    ? {
+      connectionTimeout: readPositiveInt('API_CONNECTION_TIMEOUT_MS', DEFAULT_API_CONNECTION_TIMEOUT_MS),
+      keepAliveTimeout: readPositiveInt('API_KEEP_ALIVE_TIMEOUT_MS', DEFAULT_API_KEEP_ALIVE_TIMEOUT_MS),
+      requestTimeout: readPositiveInt('API_REQUEST_TIMEOUT_MS', DEFAULT_API_REQUEST_TIMEOUT_MS),
+      maxRequestsPerSocket: readPositiveInt('API_MAX_REQUESTS_PER_SOCKET', DEFAULT_API_MAX_REQUESTS_PER_SOCKET),
+    }
+    : {};
   if (secure) {
-    options = {
-      https: {
-        key: readFileSync(keyPath),
-        cert: readFileSync(certPath),
-      }
+    options.https = {
+      key: readFileSync(keyPath),
+      cert: readFileSync(certPath),
     };
   }
 
@@ -75,11 +92,17 @@ async function bootstrap() {
     console.log(`API listening on ${address}`);
   });
 
+  const server: any = app.getHttpServer();
+  server.headersTimeout = readPositiveInt('API_HEADERS_TIMEOUT_MS', DEFAULT_API_HEADERS_TIMEOUT_MS);
+  server.maxConnections = readPositiveInt(
+    'API_MAX_CONNECTIONS_PER_WORKER',
+    DEFAULT_API_MAX_CONNECTIONS_PER_WORKER,
+  );
+  server.dropMaxConnection = true;
+
   // --- Live-reload TLS certs/keys when they change on disk ---
   if (secure) {
     // Fastify's underlying Node https server
-    const server: any = app.getHttpServer();
-
     // Guard: only HTTPS servers expose setSecureContext
     if (typeof server?.setSecureContext === 'function') {
       let reloadTimer: NodeJS.Timeout | null = null;

src/services/redis-messaging.service.spec.ts

@@ -120,6 +120,19 @@ describe('RedisMessagingService', () => {
         consoleSpy.mockRestore();
     });
 
+    it('uses an owner token when locking JSON cache refreshes', async () => {
+        await service.connect();
+
+        await expect(service.tryAcquireJsonCacheLock('summary', 'owner-a', 1000)).resolves.toBe(true);
+        await expect(service.tryAcquireJsonCacheLock('summary', 'owner-b', 1000)).resolves.toBe(false);
+
+        await service.releaseJsonCacheLock('summary', 'owner-b');
+        await expect(service.tryAcquireJsonCacheLock('summary', 'owner-b', 1000)).resolves.toBe(false);
+
+        await service.releaseJsonCacheLock('summary', 'owner-a');
+        await expect(service.tryAcquireJsonCacheLock('summary', 'owner-b', 1000)).resolves.toBe(true);
+    });
+
     it('stores payout variants and same-height reorg templates under distinct tip keys', async () => {
         await service.connect();
         const firstHash = '11'.repeat(32);
@@ -493,7 +506,10 @@ function createRedisClient() {
         connect: jest.fn().mockResolvedValue(undefined),
         quit: jest.fn().mockResolvedValue(undefined),
         on: jest.fn(),
-        set: jest.fn((key: string, value: string) => {
+        set: jest.fn((key: string, value: string, options?: { NX?: boolean }) => {
+            if (options?.NX && store.has(key)) {
+                return Promise.resolve(null);
+            }
             store.set(key, value);
             return Promise.resolve('OK');
         }),
@@ -512,6 +528,15 @@ function createRedisClient() {
             });
             return Promise.resolve(deleted);
         }),
+        eval: jest.fn((_script: string, options: { keys: string[], arguments: string[] }) => {
+            const [key] = options.keys;
+            const [owner] = options.arguments;
+            if (store.get(key) !== owner) {
+                return Promise.resolve(0);
+            }
+            store.delete(key);
+            return Promise.resolve(1);
+        }),
         sAdd: jest.fn((key: string, value: string) => {
             const set = sets.get(key) ?? new Set<string>();
             set.add(value);

src/services/redis-messaging.service.ts

@@ -32,6 +32,7 @@ const blockTemplateHeightPointerKey = (height: number, payoutMode: PayoutMode) =
 const blockTemplateLatestPointerKey = (payoutMode: PayoutMode) =>
     `${BLOCK_TEMPLATE_LATEST_KEY}:${payoutMode}`;
 const jsonCacheKey = (key: string) => `json-cache:${key}`;
+const jsonCacheLockKey = (key: string) => `json-cache-lock:${key}`;
 
 export interface BlockTemplateUpdate {
     schemaVersion: 1;
@@ -524,6 +525,41 @@ export class RedisMessagingService implements OnModuleInit, OnModuleDestroy {
         );
     }
 
+    public async tryAcquireJsonCacheLock(key: string, owner: string, ttlMs: number): Promise<boolean | null> {
+        if (!await this.ensureConnected()) {
+            return null;
+        }
+        if (owner.length === 0 || ttlMs <= 0) {
+            return false;
+        }
+
+        const result = await this.publisher.set(
+            jsonCacheLockKey(key),
+            owner,
+            { NX: true, PX: Math.max(1, Math.ceil(ttlMs)) },
+        );
+        return result === 'OK';
+    }
+
+    public async releaseJsonCacheLock(key: string, owner: string): Promise<void> {
+        if (!await this.ensureConnected() || owner.length === 0) {
+            return;
+        }
+
+        await this.publisher.eval(
+            `
+                if redis.call('GET', KEYS[1]) == ARGV[1] then
+                    return redis.call('DEL', KEYS[1])
+                end
+                return 0
+            `,
+            {
+                keys: [jsonCacheLockKey(key)],
+                arguments: [owner],
+            },
+        );
+    }
+
     private async readBlockTemplatePointer(value: string | null): Promise<IBlockTemplate | null> {
         if (value == null) {
             return null;