add tracing, env config, dotenvy

bootstrap: tracing-subscriber with RUST_LOG env filter, ServerConfig
from env vars (KFRAME_DATABASE_URL, KFRAME_TCP_ADDR, etc.), dotenvy
for .env file loading. Replaced all println with tracing macros.

tcp-server: replaced println with tracing::info/warn.

Added .env.example and .gitignore for db files.

crates/bootstrap/src/config.rs

@@ -0,0 +1,25 @@
+use std::env;
+
+pub struct ServerConfig {
+    pub database_url: String,
+    pub tcp_addr: String,
+    pub http_addr: String,
+    pub poll_interval_secs: u64,
+}
+
+impl ServerConfig {
+    pub fn from_env() -> Self {
+        Self {
+            database_url: env::var("KFRAME_DATABASE_URL")
+                .unwrap_or_else(|_| "sqlite:kframe.db?mode=rwc".into()),
+            tcp_addr: env::var("KFRAME_TCP_ADDR")
+                .unwrap_or_else(|_| "0.0.0.0:2699".into()),
+            http_addr: env::var("KFRAME_HTTP_ADDR")
+                .unwrap_or_else(|_| "0.0.0.0:3000".into()),
+            poll_interval_secs: env::var("KFRAME_POLL_INTERVAL_SECS")
+                .ok()
+                .and_then(|v| v.parse().ok())
+                .unwrap_or(5),
+        }
+    }
+}

crates/bootstrap/src/main.rs

@@ -1,3 +1,4 @@
+mod config;
 mod polling;
 
 use std::sync::Arc;
@@ -7,34 +8,50 @@ use config_sqlite::SqliteConfigStore;
 use tcp_server::{TcpBroadcaster, TcpEventBus, run_tcp_server};
 use http_api::AppState;
 use tokio::sync::Mutex;
-
-const DB_PATH: &str = "sqlite:kframe.db?mode=rwc";
-const TCP_ADDR: &str = "0.0.0.0:2699";
-const HTTP_ADDR: &str = "0.0.0.0:3000";
+use tracing::{info, error};
 
 #[tokio::main]
 async fn main() -> Result<()> {
-    let config_store = Arc::new(SqliteConfigStore::new(DB_PATH).await?);
+    dotenvy::dotenv().ok();
+
+    tracing_subscriber::fmt()
+        .with_env_filter(
+            tracing_subscriber::EnvFilter::try_from_default_env()
+                .unwrap_or_else(|_| "info,sqlx=warn".into()),
+        )
+        .init();
+
+    let cfg = config::ServerConfig::from_env();
+
+    info!(db = %cfg.database_url, "connecting to database");
+    let config_store = Arc::new(SqliteConfigStore::new(&cfg.database_url).await?);
+
     let event_bus = Arc::new(TcpEventBus::new(64));
     let broadcaster = Arc::new(TcpBroadcaster::new(64));
     let projection = Arc::new(Mutex::new(DataProjection::new()));
 
+    let tcp_addr = cfg.tcp_addr.clone();
     let tcp_bc = broadcaster.clone();
     tokio::spawn(async move {
-        run_tcp_server(TCP_ADDR, tcp_bc).await.unwrap();
+        if let Err(e) = run_tcp_server(&tcp_addr, tcp_bc).await {
+            error!(error = %e, "tcp server failed");
+        }
     });
-    println!("TCP server on {TCP_ADDR}");
+    info!(addr = %cfg.tcp_addr, "TCP server started");
 
+    let http_addr = cfg.http_addr.clone();
     let http_state = AppState {
         config: config_store.clone(),
         events: event_bus.clone(),
     };
     tokio::spawn(async move {
-        http_api::serve(HTTP_ADDR, http_state).await.unwrap();
+        if let Err(e) = http_api::serve(&http_addr, http_state).await {
+            error!(error = %e, "HTTP API failed");
+        }
     });
-    println!("HTTP API on {HTTP_ADDR}");
+    info!(addr = %cfg.http_addr, "HTTP API started");
 
-    println!("K-Frame server running");
+    info!("K-Frame server running");
 
-    polling::run(config_store, broadcaster, projection).await
+    polling::run(config_store, broadcaster, projection, cfg.poll_interval_secs).await
 }

crates/bootstrap/src/polling.rs

@@ -10,18 +10,21 @@ use http_json::HttpJsonAdapter;
 use tcp_server::TcpBroadcaster;
 use config_sqlite::SqliteConfigStore;
 use tokio::sync::Mutex;
-
-const POLL_CHECK_INTERVAL: Duration = Duration::from_secs(5);
+use tracing::{info, warn, debug};
 
 pub async fn run(
     config: Arc<SqliteConfigStore>,
     broadcaster: Arc<TcpBroadcaster>,
     projection: Arc<Mutex<DataProjection>>,
+    poll_interval_secs: u64,
 ) -> Result<()> {
     let http_adapter = HttpJsonAdapter::new();
+    let interval = Duration::from_secs(poll_interval_secs);
+
+    info!(interval_secs = poll_interval_secs, "polling loop started");
 
     loop {
-        tokio::time::sleep(POLL_CHECK_INTERVAL).await;
+        tokio::time::sleep(interval).await;
 
         let sources = config.list_data_sources().await
             .map_err(|e| anyhow::anyhow!("{e}"))?;
@@ -31,6 +34,7 @@ pub async fn run(
             .map_err(|e| anyhow::anyhow!("{e}"))?;
 
         if sources.is_empty() || widgets.is_empty() {
+            debug!("no sources or widgets configured, skipping poll");
             continue;
         }
 
@@ -40,7 +44,7 @@ pub async fn run(
             let result = match poll_source(&http_adapter, source).await {
                 Ok(v) => v,
                 Err(e) => {
-                    eprintln!("poll error for '{}': {e}", source.name);
+                    warn!(source = %source.name, error = %e, "poll failed");
                     continue;
                 }
             };
@@ -55,7 +59,7 @@ pub async fn run(
                 broadcaster.push_screen_update(l, &all_changed).await
                     .map_err(|e| anyhow::anyhow!("{e}"))?;
             }
-            println!("pushed {} widget updates", all_changed.len());
+            info!(count = all_changed.len(), "pushed widget updates");
         }
     }
 }