import: validate and create transient mount point

fixes #788

src/apps.js

@@ -153,6 +153,7 @@ const appstore = require('./appstore.js'),
     fs = require('fs'),
     mail = require('./mail.js'),
     manifestFormat = require('cloudron-manifestformat'),
+    mounts = require('./mounts.js'),
     once = require('once'),
     os = require('os'),
     path = require('path'),
@@ -1903,6 +1904,20 @@ async function importApp(app, data, auditSource) {
 
     // TODO: make this smarter to do a read-only test and check if the file exists in the storage backend
     if (backupConfig) {
+        if (mounts.isMountProvider(backupConfig.provider)) {
+            backupConfig.mountPoint = `/mnt/appimport-${app.id}`;
+            error = mounts.validateMountOptions(backupConfig.provider, backupConfig.mountOptions);
+            if (error) throw error;
+
+            const mountObject = { // keep this in sync with the import code in apptask
+                name: `appimport-${app.id}`,
+                hostPath: backupConfig.mountPoint,
+                mountType: backupConfig.provider,
+                mountOptions: backupConfig.mountOptions
+            };
+            await mounts.tryAddMount(mountObject, { timeout: 10 });
+
+        }
         error = await backups.testProviderConfig(backupConfig);
         if (error) throw error;
     }