Configuration

ServerConfig holds server settings. Build it in code, read it from the environment, load it from a TOML file (feature config-file), or layer these.

rust

use std::time::Duration;
use kerniq_server::prelude::*;

let config = ServerConfig::new()
    .host("0.0.0.0")
    .port(3000)
    .workers(4)
    .request_timeout(Duration::from_secs(30))
    .max_body_size(10 * 1024 * 1024);

let address = config.address(); // "0.0.0.0:3000"
let app = App::new().config(config).get("/", || async { "OK" });
// app.run(address).await

#Settings

Field	Default	Enforced by	Env var
`host`	`127.0.0.1`	your `run(config.address())` call	`KERNIQ_HOST`
`port`	`3000`	your `run(config.address())` call	`KERNIQ_PORT`
`workers`	CPU cores	Tokio, `run_blocking` only	`KERNIQ_WORKERS`
`request_timeout`	none	`Timeout` middleware (`408`)	`KERNIQ_REQUEST_TIMEOUT` (s)
`max_body_size`	2 MiB	body extractors (`413`)	`KERNIQ_MAX_BODY_SIZE` (bytes)
`max_connections`	unlimited	accept loop	`KERNIQ_MAX_CONNECTIONS`
`max_concurrent_requests`	unlimited	global concurrency limit	`KERNIQ_MAX_CONCURRENT_REQUESTS`
`shutdown_timeout`	30 s	graceful drain, background tasks	`KERNIQ_SHUTDOWN_TIMEOUT` (s)
`header_read_timeout`	30 s (`0` = off)	Hyper (slow-header protection)	`KERNIQ_HEADER_READ_TIMEOUT` (s)
`tcp_nodelay`	`true`	accepted sockets	`KERNIQ_TCP_NODELAY`
`connect_info`	`true`	`ConnectInfo<SocketAddr>` for handlers and `RateLimit::by_ip`	`KERNIQ_CONNECT_INFO`

Kerniq only exposes settings the underlying stack actually honors. In particular there are three distinct kinds of concurrency:

worker threads (Tokio): how many OS threads run tasks,
connections (accept loop): how many TCP connections are open,
requests (middleware): how many requests are being processed.

With #[tokio::main] you own the runtime, so workers does nothing and a warning is logged. Set threads with #[tokio::main(worker_threads = N)].

Durations from environment variables and files are in seconds and may be fractional (0.5). Booleans accept true/false/1/0/yes/no/on/off. Invalid values are reported with the variable name: invalid value "seventy" for KERNIQ_PORT: invalid digit found in string.

#Environment

rust

use kerniq_server::prelude::*;

#[tokio::main]
async fn main() -> Result<()> {
    let config = ServerConfig::from_env()?; // defaults + KERNIQ_* overrides
    let address = config.address();
    App::new().config(config).get("/", || async { "OK" }).run(address).await
}

#Files

With features = ["config-file"]:

toml

# kerniq.toml — durations in seconds, unknown keys are rejected
host = "0.0.0.0"
port = 8080
request_timeout = 30
max_concurrent_requests = 1024
shutdown_timeout = 20

rust

use kerniq_server::prelude::*;

fn load() -> Result<ServerConfig> {
    // Defaults, then the file, then the environment.
    Ok(ServerConfig::from_file("kerniq.toml")?.apply_env()?)
}

#Application settings and secrets

ServerConfig covers the server only. Keep application settings (database URLs, API keys) in your own configuration type, read secrets from the environment or a secret manager at startup, and never commit them in kerniq.toml. The modular and production CLI templates show this layout.