Add basic, not-useful websocket server

beacon_node/websocket_server/Cargo.toml

@@ -0,0 +1,17 @@
+[package]
+name = "websocket_server"
+version = "0.1.0"
+authors = ["Paul Hauner <paul@paulhauner.com>"]
+edition = "2018"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+exit-future = "0.1.3"
+futures = "0.1.25"
+serde = "1.0"
+serde_derive = "1.0"
+slog = "^2.2.3"
+tokio = "0.1.16"
+types = { path = "../../eth2/types" }
+ws = "0.9"

beacon_node/websocket_server/src/lib.rs

@@ -0,0 +1,75 @@
+use serde_derive::{Deserialize, Serialize};
+use slog::{error, info, Logger};
+use std::net::Ipv4Addr;
+use std::thread;
+use types::EthSpec;
+use ws::{Sender, WebSocket};
+
+/// The core configuration of a Lighthouse beacon node.
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct Config {
+    pub enabled: bool,
+    /// The IPv4 address the REST API HTTP server will listen on.
+    pub listen_address: Ipv4Addr,
+    /// The port the REST API HTTP server will listen on.
+    pub port: u16,
+}
+
+impl Default for Config {
+    fn default() -> Self {
+        Config {
+            enabled: true,
+            listen_address: Ipv4Addr::new(127, 0, 0, 1),
+            port: 5053,
+        }
+    }
+}
+
+pub struct WebSocketSender {
+    sender: Sender,
+}
+
+impl WebSocketSender {
+    pub fn send_string(&self, string: String) -> Result<(), String> {
+        self.sender
+            .send(string)
+            .map_err(|e| format!("Unable to broadcast to websocket clients: {:?}", e))
+    }
+}
+
+pub fn start_server<T: EthSpec>(config: &Config, log: &Logger) -> Result<WebSocketSender, String> {
+    let server_string = format!("{}:{}", config.listen_address, config.port);
+
+    info!(
+        log,
+        "Websocket server starting";
+        "listen_address" => &server_string
+    );
+
+    // Create a server that simply ignores any incoming messages.
+    let server = WebSocket::new(|_| |_| Ok(()))
+        .map_err(|e| format!("Failed to initialize websocket server: {:?}", e))?;
+
+    let broadcaster = server.broadcaster();
+
+    let log_inner = log.clone();
+    let _handle = thread::spawn(move || match server.listen(server_string) {
+        Ok(_) => {
+            info!(
+                log_inner,
+                "Websocket server stopped";
+            );
+        }
+        Err(e) => {
+            error!(
+                log_inner,
+                "Websocket server failed to start";
+                "error" => format!("{:?}", e)
+            );
+        }
+    });
+
+    Ok(WebSocketSender {
+        sender: broadcaster,
+    })
+}