This is a tiny crate that brings wait- and lock-free TLS hot-reloading to rustls. It has minimal overhead and no internal locking when it comes to resolving TLS certificates.

The main thing it provides is CertifiedKeyWatched. It implements rustls::server::ResolvesServerCert and can be used directly inside a rustls::ServerConfig as a certificate resolver. When you create a new CertifiedKeyWatched, it automatically spawns file watchers in the background that listen to modifications on these files and if they notice any, they will try to reload TLS certificates without any interruption in service.

The implementation is completely framework / server agnostic and works anywhere, where you can provide a rustls::ServerConfig. The tokio dependency only exists for spawning background tasks and async file access.

In the most simple form, the only thing you need to do is:

let tls_config =
tls_hot_reload::load_server_config("tls/key.pem".to_string(), "tls/cert.pem".to_string()).await;

If you want to build your own custom ServerConfig, you can create the CertifiedKeyWatched directly:

let ck = CertifiedKeyWatched::new(key_path, cert_path).await?;
ServerConfig::builder().with_no_client_auth().with_cert_resolver(ck)

You can also use CertifiedKeysWatched::new() to provide a Vec<BundleCert> of certificates / paths which then will be resolved via SNI from the ClientHello.