fix: prevent orphan re-adoption from reverting blue-green deploy

- Skip orphan re-adoption during active deploy (is_deploying check)
- Retry same slot if current slot has no running process instead of alternating
- Fixes revert to blue after successful green deploy

Author: Olivier Bonnaure

src/admin/handlers.rs

@@ -90,15 +90,28 @@ pub async fn get_app(state: &Arc<AdminState>, name: &str) -> Response<BoxBody> {
 pub async fn post_app_deploy(state: &Arc<AdminState>, name: &str) -> Response<BoxBody> {
     match &state.app_manager {
         Some(manager) => {
-            // Determine target slot based on current slot (alternate)
+            // Determine target slot: if current slot has no running process
+            // (e.g. after a failed auto-deploy), retry the same slot instead
+            // of alternating to the other one.
             let target_slot = manager
                 .get_app(name)
                 .await
                 .map_or("blue".to_string(), |app| {
-                    if app.current_slot == "blue" {
-                        "green".to_string()
+                    let current_pid = if app.current_slot == "blue" {
+                        app.blue.pid
                     } else {
-                        "blue".to_string()
+                        app.green.pid
+                    };
+                    if current_pid.is_some() {
+                        // Current slot is running — alternate for blue-green switch
+                        if app.current_slot == "blue" {
+                            "green".to_string()
+                        } else {
+                            "blue".to_string()
+                        }
+                    } else {
+                        // Nothing running on current slot — retry it
+                        app.current_slot.clone()
                     }
                 });
 

src/app/mod.rs

@@ -1378,6 +1378,14 @@ impl AppManager {
                     continue;
                 }
                 if let Some(found_pid) = find_pid_by_port(port) {
+                    if self.deployment_manager.is_deploying(&app_name) {
+                        tracing::debug!(
+                            "Skipping orphan re-adoption for {} on port {} — deploy in progress",
+                            app_name,
+                            port
+                        );
+                        continue;
+                    }
                     tracing::warn!(
                         "Re-adopting orphaned process PID {} on port {} for {} slot {}",
                         found_pid,

src/main.rs

@@ -421,10 +421,19 @@ fn run_app_command(config_path: &str, app_name: &str, action: &str) -> Result<()
                         .get_app(app_name)
                         .await
                         .map_or("blue".to_string(), |app| {
-                            if app.current_slot == "blue" {
-                                "green".to_string()
+                            let current_pid = if app.current_slot == "blue" {
+                                app.blue.pid
                             } else {
-                                "blue".to_string()
+                                app.green.pid
+                            };
+                            if current_pid.is_some() {
+                                if app.current_slot == "blue" {
+                                    "green".to_string()
+                                } else {
+                                    "blue".to_string()
+                                }
+                            } else {
+                                app.current_slot.clone()
                             }
                         });
                 app_manager.deploy(app_name, &target_slot).await?;