provide tracing (#13)

Cargo.toml

@@ -20,6 +20,7 @@ serde = { version = "1.0.195", features = ["derive"] }
 serde_json = "1"
 tower = "0.4"
 tower-sessions-core = "0.12.0"
+tracing = { version = "0.1.40", features = ["log"] }
 
 [dev-dependencies]
 axum = { version = "0.7.0", features = ["macros"] }

src/lib.rs

@@ -251,6 +251,16 @@ impl Messages {
  self
  }
 
+ /// Returns the number of messages to be read.
+ pub fn len(&self) -> usize {
+ self.data.lock().messages.len()
+ }
+
+ /// Returns `true` if there are no messages.
+ pub fn is_empty(&self) -> bool {
+ self.data.lock().messages.is_empty()
+ }
+
  async fn save(self) -> Result<Self, session::Error> {
  self.session
  .insert(Self::DATA_KEY, self.data.clone())
@@ -338,31 +348,37 @@ where
 
  Box::pin(async move {
  let Some(session) = req.extensions().get::<Session>().cloned() else {
+ tracing::error!(
+ "session not found in request extensions; do tower-sessions versions match?"
+ );
  let mut res = Response::default();
  *res.status_mut() = http::StatusCode::INTERNAL_SERVER_ERROR;
  return Ok(res);
  };
 
- let data = match session.get::<Data>(Messages::DATA_KEY).await {
+ let data = match session.get(Messages::DATA_KEY).await {
  Ok(Some(data)) => data,
  Ok(None) => Data::default(),
- Err(_) => {
+ Err(err) => {
+ tracing::error!(err = %err, "could not load messages data");
  let mut res = Response::default();
  *res.status_mut() = http::StatusCode::INTERNAL_SERVER_ERROR;
  return Ok(res);
  }
  };
 
  let messages = Messages::new(session, data);
-
  req.extensions_mut().insert(messages.clone());
 
  let res = inner.call(req).await;
 
- if messages.is_modified() && messages.save().await.is_err() {
- let mut res = Response::default();
- *res.status_mut() = http::StatusCode::INTERNAL_SERVER_ERROR;
- return Ok(res);
+ if messages.is_modified() {
+ if let Err(err) = messages.save().await {
+ tracing::error!(err = %err, "could not save messages data");
+ let mut res = Response::default();
+ *res.status_mut() = http::StatusCode::INTERNAL_SERVER_ERROR;
+ return Ok(res);
+ }
  };
 
  res