Notify application on state changes

Author: davidsteiner

crates/hotfix/src/application.rs

@@ -1,4 +1,5 @@
 use crate::message::OutboundMessage;
+use crate::session::Status;
 use hotfix_message::message::Message;
 
 #[async_trait::async_trait]
@@ -18,6 +19,11 @@ pub trait Application: Send + Sync + 'static {
     async fn on_logout(&mut self, reason: &str);
     /// Called when the session is logged on.
     async fn on_logon(&mut self);
+    /// Called when the session state changes.
+    ///
+    /// This is invoked after every state transition, providing the previous
+    /// and new status. The default implementation does nothing.
+    async fn on_state_change(&self, from: &Status, to: &Status);
 }
 
 /// Standard FIX Business Reject Reason values (tag 380).

crates/hotfix/src/session.rs

@@ -482,7 +482,15 @@ where
 
     async fn apply_transition(&mut self, result: TransitionResult) {
         if let TransitionResult::TransitionTo(new_state) = result {
+            let old_status = self.state.as_status();
             self.state = new_state;
+            let new_status = self.state.as_status();
+            if old_status != new_status {
+                self.ctx
+                    .application
+                    .on_state_change(&old_status, &new_status)
+                    .await;
+            }
         }
     }
 

examples/load-testing/src/application.rs

@@ -2,6 +2,7 @@ use crate::messages::{ExecutionReport, InboundMsg, OutboundMsg};
 use hotfix::Application;
 use hotfix::Message;
 use hotfix::application::{InboundDecision, OutboundDecision};
+use hotfix::session::Status;
 use tokio::sync::mpsc::UnboundedSender;
 use tracing::info;
 
@@ -51,4 +52,8 @@ impl Application for LoadTestingApplication {
     async fn on_logon(&mut self) {
         info!("we've been logged in");
     }
+
+    async fn on_state_change(&self, from: &Status, to: &Status) {
+        info!("we've changed from {:?} to {:?}", from, to);
+    }
 }

examples/order-entry/src/application.rs

@@ -1,15 +1,15 @@
 use std::sync::{Arc, Mutex};
 
+use crate::messages::OutboundMsg;
 use hotfix::Application;
 use hotfix::Message;
 use hotfix::application::{InboundDecision, OutboundDecision};
 use hotfix::message::OutboundMessage;
+use hotfix::session::Status;
 use hotfix_message::message::Config as EncodeConfig;
 use serde::Serialize;
 use tracing::info;
 
-use crate::messages::OutboundMsg;
-
 #[derive(Clone, Serialize)]
 pub struct MessageLogEntry {
     pub id: u64,
@@ -91,4 +91,8 @@ impl Application for TestApplication {
     async fn on_logon(&mut self) {
         info!("we've been logged in");
     }
+
+    async fn on_state_change(&self, from: &Status, to: &Status) {
+        info!("we've changed from {:?} to {:?}", from, to);
+    }
 }