Chapter 18: System Initialization and Server Settings

This chapter describes process initialization, socket options, backpressure, capacity, metrics, and graceful shutdown as separate configuration areas.

1. ServerSetting handles process-level initialization

ServerSetting configures signal defaults and the framework logger. Socket options, backpressure, HTTP limits, Worker queue limits, and graceful shutdown belong to each server instance.

2. Initialize signals and logging

stt::file::LogFile log(16384);
if(!log.openFile("logs/sttnet.log", "yyyy-mm-ddThh:mi:ss.sss", "  "))
    return 1;

// "Chinese" selects Chinese framework messages; other values select English.
stt::system::ServerSetting::init(&log, "English");

init() combines setExceptionHandling() and setLogFile(). The logger lifetime extends beyond the network server lifetime.

3. Socket options

ServerSocketOptions options;
options.tcp_no_delay = true;
options.keep_alive = true;
options.keep_alive_idle_seconds = 60;
options.keep_alive_interval_seconds = 10;
options.keep_alive_probe_count = 3;
options.listen_backlog = 4096;
server.setSocketOptions(options);

4. Memory, backpressure, and task limits

Setting	Protection
`setMaxPendingWriteBytes`	Caps per-connection memory held for slow clients
`setWriteBudgetPerEvent`	Prevents one connection from monopolizing writes
`setMaxHttpHeaderBytes`	Rejects oversized HTTP headers
`setMaxPendingWorkerTasks`	Rejects work instead of growing an unbounded queue
`setGracefulShutdownTimeout`	Bounds close-time draining

5. Metrics snapshot

const ServerMetricsSnapshot m = server.getMetrics();
std::cout << "connections=" << m.active_connections << '
'
          << "http_requests=" << m.parsed_http_requests << '
'
          << "pending_write_bytes=" << m.pending_write_bytes << '
'
          << "worker_rejections=" << m.worker_task_rejections << '
';

6. Framework capacity is not an OS limit

HttpServer(100000, ...) does not raise Linux file-descriptor limits. Actual capacity also depends on ulimit -n, systemd LimitNOFILE, kernel backlogs, and ephemeral ports.

Complete system settings demo →