feat: add persistence for last deployment path in Nginx handler

apps/nxmesh-agent/src/service/nginx_handler/fs_handler.rs

@@ -56,6 +56,14 @@ pub trait FsHandler: Send + Sync + 'static {
     // clean up old config files that are applied to nginx
     // keep only latest n deployments.
     async fn cleanup_config(&self, n: usize) -> Result<()>;
+
+    // Persist the root config path of the last successful deployment.
+    // Survives agent restarts so Reload/Test commands work without a new ConfigUpdate.
+    async fn save_last_deployment(&self, root_config_path: &str) -> Result<()>;
+
+    // Load the last persisted root config path, if any.
+    // Returns Ok(None) when no state file exists or it is empty/corrupt.
+    async fn load_last_deployment(&self) -> Result<Option<String>>;
 }
 
 pub struct FsHandlerImpl {
@@ -91,6 +99,10 @@ impl FsHandlerImpl {
         self.get_deployment_dir().join(deployment_id)
     }
 
+    fn get_state_file_path(&self) -> std::path::PathBuf {
+        std::path::Path::new(&self.settings.nginx_config_path).join(".last_deployment")
+    }
+
     async fn get_deployment_config_path(
         &self,
         deployment_id: &str,
@@ -183,6 +195,58 @@ impl FsHandler for FsHandlerImpl {
         Ok(full_output_path.to_string_lossy().to_string())
     }
 
+    async fn save_last_deployment(&self, root_config_path: &str) -> Result<()> {
+        let state_path = self.get_state_file_path();
+        let tmp_path = state_path.with_extension("tmp");
+        tokio::fs::write(&tmp_path, format!("{}\n", root_config_path)).await?;
+        tokio::fs::rename(&tmp_path, &state_path).await?;
+        Ok(())
+    }
+
+    async fn load_last_deployment(&self) -> Result<Option<String>> {
+        // primary: try state file
+        let state_path = self.get_state_file_path();
+        if state_path.exists() {
+            let content = tokio::fs::read_to_string(&state_path).await?;
+            let path = content.trim().to_string();
+            if !path.is_empty() {
+                return Ok(Some(path));
+            }
+        }
+
+        // fallback: scan deployments directory for the newest deployment
+        let deployment_dir = self.get_deployment_dir();
+        if !deployment_dir.exists() {
+            return Ok(None);
+        }
+        let mut entries = tokio::fs::read_dir(&deployment_dir).await?;
+        let mut candidates: Vec<(std::path::PathBuf, std::time::SystemTime)> = Vec::new();
+        while let Some(entry) = entries.next_entry().await? {
+            if entry.file_type().await.map_or(false, |t| t.is_dir()) {
+                if let Ok(mtime) = entry.metadata().await.and_then(|m| m.modified()) {
+                    candidates.push((entry.path(), mtime));
+                }
+            }
+        }
+        // sort descending by mtime (newest first)
+        candidates.sort_by(|a, b| b.1.cmp(&a.1));
+
+        for (dir, _) in &candidates {
+            let mut dir_entries = tokio::fs::read_dir(dir).await?;
+            while let Some(file) = dir_entries.next_entry().await? {
+                if file.file_type().await.map_or(false, |t| t.is_file()) {
+                    let name = file.file_name().to_string_lossy().to_string();
+                    if name == "nginx.conf" || name.ends_with(".conf") {
+                        let path = file.path().to_string_lossy().to_string();
+                        return Ok(Some(path));
+                    }
+                }
+            }
+        }
+
+        Ok(None)
+    }
+
     async fn cleanup_config(&self, n: usize) -> Result<()> {
         let deployment_dir = self.get_deployment_dir();
         // loop through all files in the deployment dir and delete them

apps/nxmesh-agent/src/service/nginx_handler/message_handler.rs

@@ -6,7 +6,7 @@ use nxmesh_proto::{
     agent_message::Payload::ConfigUpdateResult as ConfigUpdateResultPayload, command::Command,
     command_result,
 };
-use tracing::warn;
+use tracing::{info, warn};
 
 use crate::{
     config::settings::NginxSettings,
@@ -106,6 +106,9 @@ impl OnConfigUpdateHandler for NginxMasterMessageHandlerImpl {
         }
         // apply reload on the root config
         self.command_handler.reload(Some(&root_config_path)).await?;
+        // persist deployment path so Reload/Test commands survive agent restarts
+        self.fs_handler.save_last_deployment(&root_config_path).await?;
+        info!("Persisted last deployment path: {}", root_config_path);
         // Reply the master to confirm the config update is successful
         self.master_handler
             .send_message_to_master(nxmesh_proto::AgentMessage {
@@ -141,17 +144,25 @@ impl OnCommandHandler for NginxMasterMessageHandlerImpl {
             message_id: message_id.to_string(),
             payload: None,
         };
+        // load the last known deployment path for use with Reload/Test commands
+        let last_config_path = self.fs_handler.load_last_deployment().await?;
+
         let result: command_result::Result = match command {
-            // TODO: should use the previous config path
             Command::Reload(_) => {
-                let result = self.command_handler.reload(None).await;
+                let result = self
+                    .command_handler
+                    .reload(last_config_path.as_deref())
+                    .await;
                 command_result::Result::ReloadResult(nxmesh_proto::ReloadResult {
                     success: result.is_ok(),
                     error_message: result.err().map(|e| e.to_string()).unwrap_or_default(),
                 })
             }
             Command::Test(_) => {
-                let result = self.command_handler.validate(None).await;
+                let result = self
+                    .command_handler
+                    .validate(last_config_path.as_deref())
+                    .await;
                 command_result::Result::TestResult(nxmesh_proto::TestResult {
                     success: result.is_ok(),
                     error_message: result.err().map(|e| e.to_string()).unwrap_or_default(),

crates/nxmesh-proto/proto/agent.proto

@@ -68,8 +68,9 @@ message ConfigContent {
 
 message ConfigUpdateResult {
   string config_id = 1; // should match the config_id in ConfigUpdate
-  bool success = 2;
+  string version = 2;
-  ConfigUpdateError error_message = 3; // if success is false, this field should contain the error message
+  bool success = 3;
+  optional ConfigUpdateError error_message = 4; // if success is false, this field should contain the error message
 }
 
 enum ConfigUpdateError {
@@ -83,6 +84,8 @@ enum ConfigUpdateError {
 //
 //
 
+// TODO: allow setting the default fallback and the corresponding default nginx root config when nginx reload fails to re-use old config, "use default config", "stop nginx".
+
 // Command represents a request from master to agent to execute a command, e.g. "reload", "test"
 message Command {
   oneof command {