vmm: Add backup status flag in VmInfo in the RPC

Author: kvinwang

vmm/rpc/proto/vmm_rpc.proto

@@ -31,6 +31,8 @@ message VmInfo {
   string shutdown_progress = 12;
   // Image version
   string image_version = 13;
+  // Backup in progress
+  bool backup_in_progress = 14;
 }
 
 message Id {

vmm/src/app.rs

@@ -684,6 +684,8 @@ impl App {
         };
 
         let qmp_socket = work_dir.qmp_socket();
+        let _lock = BackupLock::try_lock(work_dir.backup_lock_file())
+            .context("Failed to lock for backup")?;
 
         let id = id.to_string();
         tokio::task::spawn_blocking(move || {
@@ -896,6 +898,30 @@ impl App {
     }
 }
 
+struct BackupLock {
+    path: PathBuf,
+}
+
+impl BackupLock {
+    fn try_lock(path: impl AsRef<Path>) -> Result<Self> {
+        let path = path.as_ref();
+        let _file = fs::OpenOptions::new()
+            .create_new(true)
+            .write(true)
+            .open(path)
+            .context("Failed to create backup lock file")?;
+        Ok(BackupLock {
+            path: path.to_path_buf(),
+        })
+    }
+}
+
+impl Drop for BackupLock {
+    fn drop(&mut self) {
+        fs::remove_file(&self.path).ok();
+    }
+}
+
 fn paginate<T>(items: Vec<T>, page: u32, page_size: u32) -> impl Iterator<Item = T> {
     let skip;
     let take;

vmm/src/app/qemu.rs

@@ -168,6 +168,7 @@ impl VmInfo {
             app_id: self.manifest.app_id.clone(),
             instance_id: self.instance_id.as_deref().map(Into::into),
             exited_at: self.exited_at.clone(),
+            backup_in_progress: workdir.backup_lock_file().exists(),
         }
     }
 }
@@ -731,6 +732,10 @@ impl VmWorkDir {
     pub fn path(&self) -> &Path {
         &self.workdir
     }
+
+    pub fn backup_lock_file(&self) -> PathBuf {
+        self.workdir.join("backup.lock")
+    }
 }
 
 impl VmWorkDir {

vmm/src/console.html

@@ -2503,6 +2503,14 @@ <h5>Backup ID: {{ group.backup_id }}</h5>
                 };
 
                 const vmStatus = (vm) => {
+                    const status = vmStatus0(vm);
+                    if (vm.backup_in_progress) {
+                        return status + ' (backing up)';
+                    }
+                    return status;
+                }
+
+                const vmStatus0 = (vm) => {
                     const features = imageFeatures(vm);
                     if (!features.progress) {
                         return vm.status;