Cap concurrent API connections

.env.example

@@ -39,6 +39,7 @@ 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

docker-compose.external-db.yml

@@ -79,6 +79,7 @@ services:
       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}

docker-compose.yml

@@ -109,6 +109,7 @@ services:
       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}

full-setup/docker-compose-mainnet.yml

@@ -113,6 +113,7 @@ services:
       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: "true"
       STRATUM_WORKERS: ${STRATUM_WORKERS:-2}
       STRATUM_MIN_DIFFICULTY: ${STRATUM_MIN_DIFFICULTY:-1}

src/main.ts

@@ -15,6 +15,7 @@ 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]);
@@ -93,6 +94,11 @@ async function bootstrap() {
 
   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) {