feat: add configuration through file

A file named `config.toml` can now be used to load the address, port,
and some websocket configuration settings.

Fixes https://todo.sr.ht/~gheartsfield/nostr-rs-relay/3

src/config.rs

@@ -0,0 +1,81 @@
+use serde::{Deserialize, Serialize};
+
+#[derive(Debug, Serialize, Deserialize)]
+#[allow(unused)]
+pub struct Network {
+    pub port: u16,
+    pub address: String,
+}
+
+#[derive(Debug, Serialize, Deserialize)]
+#[allow(unused)]
+pub struct Retention {
+    // TODO: implement
+    pub max_events: Option<usize>,        // max events
+    pub max_bytes: Option<usize>,         // max size
+    pub persist_days: Option<usize>,      // oldest message
+    pub whitelist_addresses: Vec<String>, // whitelisted addresses (never delete)
+}
+
+#[derive(Debug, Serialize, Deserialize)]
+#[allow(unused)]
+pub struct Limits {
+    pub messages_per_sec: Option<usize>, // Artificially slow down event writing to limit disk consumption
+    pub max_event_bytes: Option<usize>,
+    pub max_ws_message_bytes: Option<usize>,
+    pub max_ws_frame_bytes: Option<usize>,
+    pub broadcast_buffer: usize, // events to buffer for subscribers (prevents slow readers from consuming memory)
+    pub event_persist_buffer: usize, // events to buffer for database commits (block senders if database writes are too slow)
+}
+
+#[derive(Debug, Serialize, Deserialize)]
+#[allow(unused)]
+pub struct Settings {
+    pub network: Network,
+    pub limits: Limits,
+    pub retention: Retention,
+}
+
+impl Settings {
+    pub fn new() -> Self {
+        let d = Self::default();
+        // attempt to construct settings with file
+        Self::new_from_default(&d).unwrap_or(d)
+    }
+
+    fn new_from_default(default: &Settings) -> Result<Self, config::ConfigError> {
+        let config: config::Config = config::Config::new();
+        let settings: Settings = config
+            // use defaults
+            .with_merged(config::Config::try_from(default).unwrap())?
+            // override with file contents
+            .with_merged(config::File::with_name("config"))?
+            .try_into()?;
+        Ok(settings)
+    }
+}
+
+impl Default for Settings {
+    fn default() -> Self {
+        Settings {
+            network: Network {
+                port: 8080,
+                address: "0.0.0.0".to_owned(),
+            },
+            limits: Limits {
+                messages_per_sec: None,
+                max_event_bytes: Some(2 << 17),      // 128K
+                max_ws_message_bytes: Some(2 << 17), // 128K
+                max_ws_frame_bytes: Some(2 << 17),   // 128K
+                broadcast_buffer: 4096,
+                event_persist_buffer: 16,
+            },
+            retention: Retention {
+                max_events: None,            // max events
+                max_bytes: None,             // max size
+                persist_days: None,          // oldest message
+                whitelist_addresses: vec![], // whitelisted addresses (never delete)
+            },
+        }
+    }
+}

src/error.rs

@@ -34,6 +34,8 @@ pub enum Error {
     CommandUnknownError,
     #[error("SQL error")]
     SqlError(rusqlite::Error),
+    #[error("Config error")]
+    ConfigError(config::ConfigError),
 }
 
 impl From<rusqlite::Error> for Error {
@@ -56,3 +58,10 @@ impl From<WsError> for Error {
         Error::WebsocketError(r)
     }
 }
+
+impl From<config::ConfigError> for Error {
+    /// Wrap Config error
+    fn from(r: config::ConfigError) -> Self {
+        Error::ConfigError(r)
+    }
+}

src/lib.rs

@@ -1,4 +1,5 @@
 pub mod close;
+pub mod config;
 pub mod conn;
 pub mod db;
 pub mod error;

src/main.rs

@@ -1,8 +1,10 @@
 //! Server process
 use futures::SinkExt;
 use futures::StreamExt;
+use lazy_static::lazy_static;
 use log::*;
 use nostr_rs_relay::close::Close;
+use nostr_rs_relay::config;
 use nostr_rs_relay::conn;
 use nostr_rs_relay::db;
 use nostr_rs_relay::error::{Error, Result};
@@ -11,7 +13,7 @@ use nostr_rs_relay::protostream;
 use nostr_rs_relay::protostream::NostrMessage::*;
 use nostr_rs_relay::protostream::NostrResponse::*;
 use std::collections::HashMap;
-use std::env;
+use std::sync::RwLock;
 use tokio::net::{TcpListener, TcpStream};
 use tokio::runtime::Builder;
 use tokio::sync::broadcast;
@@ -19,14 +21,24 @@ use tokio::sync::broadcast::{Receiver, Sender};
 use tokio::sync::mpsc;
 use tokio::sync::oneshot;
 use tungstenite::protocol::WebSocketConfig;
+// initialize a singleton default configuration
+lazy_static! {
+    static ref SETTINGS: RwLock<config::Settings> = RwLock::new(config::Settings::default());
+}
 
 /// Start running a Nostr relay server.
 fn main() -> Result<(), Error> {
-    // setup logger and environment
+    // setup logger
     let _ = env_logger::try_init();
-    let addr = env::args()
-        .nth(1)
-        .unwrap_or_else(|| "0.0.0.0:8080".to_string());
+    {
+        let mut settings = SETTINGS.write().unwrap();
+        // replace default settings with those read from config.toml
+        let c = config::Settings::new();
+        debug!("using settings: {:?}", c);
+        *settings = c;
+    }
+    let config = SETTINGS.read().unwrap();
+    let addr = format!("{}:{}", config.network.address.trim(), config.network.port);
     // configure tokio runtime
     let rt = Builder::new_multi_thread()
         .enable_all()
@@ -35,16 +47,17 @@ fn main() -> Result<(), Error> {
         .unwrap();
     // start tokio
     rt.block_on(async {
+        let settings = SETTINGS.read().unwrap();
         let listener = TcpListener::bind(&addr).await.expect("Failed to bind");
         info!("listening on: {}", addr);
         // all client-submitted valid events are broadcast to every
         // other client on this channel.  This should be large enough
         // to accomodate slower readers (messages are dropped if
         // clients can not keep up).
-        let (bcast_tx, _) = broadcast::channel::<Event>(4096);
+        let (bcast_tx, _) = broadcast::channel::<Event>(settings.limits.broadcast_buffer);
         // validated events that need to be persisted are sent to the
         // database on via this channel.
-        let (event_tx, event_rx) = mpsc::channel::<Event>(16);
+        let (event_tx, event_rx) = mpsc::channel::<Event>(settings.limits.event_persist_buffer);
         // start the database writer thread.  Give it a channel for
         // writing events, and for publishing events that have been
         // written (to all connected clients).
@@ -94,13 +107,12 @@ async fn nostr_server(
 ) {
     // get a broadcast channel for clients to communicate on
     let mut bcast_rx = broadcast.subscribe();
-    // websocket configuration / limits
-    let config = WebSocketConfig {
-        max_send_queue: None,
-        max_message_size: Some(2 << 19), // 512K
-        max_frame_size: Some(2 << 19),   // 512k
-        accept_unmasked_frames: false,   // follow the spec
-    };
+    let mut config = WebSocketConfig::default();
+    {
+        let settings = SETTINGS.read().unwrap();
+        config.max_message_size = settings.limits.max_ws_message_bytes;
+        config.max_frame_size = settings.limits.max_ws_frame_bytes;
+    }
     // upgrade the TCP connection to WebSocket
     let conn = tokio_tungstenite::accept_async_with_config(stream, Some(config)).await;
     let ws_stream = conn.expect("websocket handshake error");