Properly configure tracing subscriber (#9)

Uses the EnvFilter with tracing_subscriber, and will hopefully avoid
printing ANSI escape codes in prod.

Cargo.toml

@@ -11,7 +11,7 @@ reqwest = { version = "0.11.26", features = ["json"] }
 serde = { version = "1.0.197", features = ["derive"] }
 serde_json = "1.0.114"
 tracing = "0.1.28"
-tracing-subscriber = "0.3.18"
+tracing-subscriber = { version = "0.3.18", features = ["env-filter", "fmt"] }
 tungstenite = { version = "0.21.0", features = ["handshake", "native-tls"]}
 uuid = { version = "1.7.0", features = ["v4", "serde"] }
 rand = "0.8.5"

src/healthcheck.rs

@@ -12,8 +12,8 @@ pub async fn start_http_server() -> tokio::io::Result<()> {
         let (mut socket, _) = listener.accept().await?;
         tokio::spawn(async move {
             match socket.peer_addr() {
-                Ok(peer_addr) => tracing::info!("Handling connection from {}", peer_addr),
-                Err(err) => tracing::info!("Handling connection from unknown peer {}", err),
+                Ok(peer_addr) => tracing::debug!("Handling connection from {}", peer_addr),
+                Err(err) => tracing::debug!("Handling connection from unknown peer {}", err),
             }
             let response = "HTTP/1.1 200 OK\r\nContent-Type: text/plain\r\n\r\nHealthcheck OK";
             let _ = socket.write_all(response.as_bytes()).await;

src/main.rs

@@ -1,5 +1,7 @@
 use crate::healthcheck::start_http_server;
 use crate::slack::start_websocket_client;
+use tracing_subscriber::layer::SubscriberExt;
+use tracing_subscriber::util::SubscriberInitExt;
 
 mod healthcheck;
 mod roulette;
@@ -8,9 +10,9 @@ mod slack_message;
 
 #[tokio::main]
 async fn main() {
-    tracing_subscriber::fmt()
-        .with_max_level(tracing::Level::INFO)
-        .with_ansi(true)
+    tracing_subscriber::registry()
+        .with(tracing_subscriber::fmt::layer().with_ansi(std::env::var("TERM").is_ok()))
+        .with(tracing_subscriber::EnvFilter::from_default_env())
         .init();
     let app_handle = tokio::spawn(async move {
         start_websocket_client().await;

src/slack.rs

@@ -128,6 +128,8 @@ async fn handle_disconnect_message(
     message: incoming::SlackDisconnectIncomingMessage,
     client: &Client,
 ) -> Option<SlackWebSocket> {
+    tracing::info!("Received disconnect message: {:?}", message.reason.as_str());
+
     match message.reason.as_str() {
         "link_disabled" => {
             tracing::info!("Link disabled, stopping bot");