test(vhost-user): extract backend spawn helper to utils

Extracted spawn_vhost_user_backend() into
util_vhost_user_backend.py as it will be used
by multiple test files.

Signed-off-by: Nikita Kalyazin <[email protected]>

Author: kalyazin

tests/framework/utils_vhost_user_backend.py

@@ -0,0 +1,37 @@
+# Copyright 2023 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+# SPDX-License-Identifier: Apache-2.0
+
+"""Utilities for vhost-user-blk backend."""
+
+import os
+import subprocess
+import time
+
+from framework import utils
+
+VHOST_USER_SOCKET = "/vub.socket"
+
+
+def spawn_vhost_user_backend(vm, host_mem_path, readonly=False):
+    """Spawn vhost-user-blk backend."""
+
+    uid = vm.jailer.uid
+    gid = vm.jailer.gid
+
+    socket_path = f"{vm.chroot()}{VHOST_USER_SOCKET}"
+    args = ["vhost-user-blk", "-s", socket_path, "-b", host_mem_path]
+    if readonly:
+        args.append("-r")
+    proc = subprocess.Popen(args)
+
+    # Give the backend time to initialise.
+    time.sleep(1)
+
+    assert proc is not None and proc.poll() is None, "backend is not up"
+
+    with utils.chroot(vm.chroot()):
+        # The backend will create the socket path with root rights.
+        # Change rights to the jailer's.
+        os.chown(VHOST_USER_SOCKET, uid, gid)
+
+    return proc

tests/integration_tests/functional/test_drive_vhost_user.py

@@ -2,34 +2,11 @@
 # SPDX-License-Identifier: Apache-2.0
 """Tests for vhost-user-block device."""
 
-import os
-import subprocess
-import time
-
 from framework import utils
-
-VHOST_USER_SOCKET = "/vub.socket"
-
-
-def spawn_vhost_user_backend(vm, host_mem_path):
-    """Spawn vhost-user-block backend."""
-
-    uid = vm.jailer.uid
-    gid = vm.jailer.gid
-
-    sp = f"{vm.chroot()}{VHOST_USER_SOCKET}"
-    args = ["vhost-user-blk", "-s", sp, "-b", host_mem_path, "-r"]
-    proc = subprocess.Popen(args)
-
-    time.sleep(1)
-    if proc is None or proc.poll() is not None:
-        print("vub is not running")
-
-    with utils.chroot(vm.chroot()):
-        # The backend will create the socket path with root rights.
-        # Change rights to the jailer's.
-        os.chown(VHOST_USER_SOCKET, uid, gid)
-    return proc
+from framework.utils_vhost_user_backend import (
+    VHOST_USER_SOCKET,
+    spawn_vhost_user_backend,
+)
 
 
 def test_vhost_user_block(microvm_factory, guest_kernel, rootfs_ubuntu_22):
@@ -48,7 +25,7 @@ def test_vhost_user_block(microvm_factory, guest_kernel, rootfs_ubuntu_22):
     # Converting path from tmpfs ("./srv/..") to local
     # path on the host ("../build/..")
     rootfs_path = utils.to_local_dir_path(str(rootfs_ubuntu_22))
-    _backend = spawn_vhost_user_backend(vm, rootfs_path)
+    _backend = spawn_vhost_user_backend(vm, rootfs_path, readonly=True)
 
     vm.basic_config()
     vm.add_vhost_user_block("1", VHOST_USER_SOCKET, is_root_device=True)