[vm factory] using the new read_from function to read the cloud-init-…

…config.iso instead of mounting.

include/multipass/cloud_init_iso.h

@@ -32,6 +32,7 @@ class CloudInitIso
 {
 public:
     void add_file(const std::string& name, const std::string& data);
+    void replace_file(const std::string& name, const std::string& data);
     void write_to(const Path& path);
     void read_from(const std::filesystem::path& path);
 

src/iso/cloud_init_iso.cpp

@@ -471,6 +471,21 @@ void mp::CloudInitIso::add_file(const std::string& name, const std::string& data
     files.push_back(FileEntry{name, data});
 }
 
+void mp::CloudInitIso::replace_file(const std::string& name, const std::string& data)
+{
+    if (auto iter = std::find_if(files.begin(),
+                                 files.end(),
+                                 [name](const FileEntry& file_entry) -> bool { return file_entry.name == name; });
+        iter == std::end(files))
+    {
+        throw std::runtime_error("Did not find the target file in the file list");
+    }
+    else
+    {
+        *iter = FileEntry{name, data};
+    }
+}
+
 void mp::CloudInitIso::write_to(const Path& path)
 {
     QFile f{path};

src/platform/backends/qemu/qemu_virtual_machine_factory.cpp

@@ -80,61 +80,20 @@ mp::VirtualMachine::UPtr mp::QemuVirtualMachineFactory::create_vm_and_instance_d
                     dest_instance_data_directory,
                     std::filesystem::copy_options::recursive);
 
+    const fs::path cloud_init_config_iso_file_path = dest_instance_data_directory / "cloud-init-config.iso";
+    CloudInitIso qemu_iso;
+    qemu_iso.read_from(cloud_init_config_iso_file_path);
     const YAML::Node network_data =
         mpu::make_cloud_init_network_config(dest_vm_spec.default_mac_address, dest_vm_spec.extra_interfaces);
-    CloudInitIso qemu_iso;
     if (!network_data.IsNull())
     {
-        qemu_iso.add_file("network-config", mpu::emit_cloud_config(network_data));
-    }
-    const YAML::Node meta_data = mpu::make_cloud_init_meta_config(destination_name);
-    qemu_iso.add_file("meta-data", mpu::emit_cloud_config(meta_data));
-
-    // create the mount folder
-    const fs::path cloud_init_mount_point = dest_instance_data_directory / "cidata";
-    if (std::error_code err; !MP_FILEOPS.create_directory(cloud_init_mount_point, err))
-    {
-        throw std::runtime_error{
-            fmt::format("Could not create mount point for cloud-init-config.iso file of the instance: {} ",
-                        destination_name)};
-    }
-
-    // sudo mount -o loop cloud-init-config.iso
-    // /root/.local/share/multipassd/vault/instances/adaptive-cat-clone/cidata
-    const fs::path cloud_init_config_iso_file_path = dest_instance_data_directory / "cloud-init-config.iso";
-    const std::string mount_command =
-        fmt::format("mount -o loop {} {}", cloud_init_config_iso_file_path.string(), cloud_init_mount_point.string());
-    if (int return_code = std::system(mount_command.c_str()); return_code != 0)
-    {
-        throw std::runtime_error{fmt::format("Error executing command : {} ", mount_command)};
+        qemu_iso.replace_file("network-config", mpu::emit_cloud_config(network_data));
     }
 
-    // load files and add to qemu_iso and write to the .iso file
-    for (const auto filename_str : {"user-data", "vendor-data"})
-    {
-        const auto stream = MP_FILEOPS.open_read(cloud_init_mount_point / fs::path(filename_str));
-        std::stringstream buffer;
-        buffer << stream->rdbuf();
-        const std::string file_contents = buffer.str();
-        qemu_iso.add_file(filename_str, file_contents);
-    }
+    const YAML::Node meta_data = mpu::make_cloud_init_meta_config(destination_name);
+    qemu_iso.replace_file("meta-data", mpu::emit_cloud_config(meta_data));
     qemu_iso.write_to(QString::fromStdString(cloud_init_config_iso_file_path.string()));
 
-    // sudo umount /root/.local/share/multipassd/vault/instances/adaptive-cat-clone/cidata
-    const std::string unmount_command = fmt::format("umount {}", cloud_init_mount_point.string());
-    if (int return_code = std::system(unmount_command.c_str()); return_code != 0)
-    {
-        throw std::runtime_error{fmt::format("Error executing command : {} ", unmount_command)};
-    }
-
-    // delete the created mount folder
-    if (std::error_code err; !MP_FILEOPS.remove(cloud_init_mount_point, err))
-    {
-        throw std::runtime_error{
-            fmt::format("Could not remove mount point for cloud-init-config.iso file of the instance: {} ",
-                        destination_name)};
-    }
-
     // start to construct VirtualMachineDescription
     mp::VirtualMachineDescription dest_vm_desc{dest_vm_spec.num_cores,
                                                dest_vm_spec.mem_size,