separate docker build

build-docker

@@ -0,0 +1,75 @@
+#!/usr/bin/env python3
+
+import os
+
+import common
+import subprocess
+import tarfile
+import time
+
+parser = common.get_argparse(argparse_args={
+    'description': '''\
+Build a guest root filesystem based on prebuilt Docker Ubuntu root filesystems.
+
+See also:https://github.com/cirosantilli/linux-kernel-module-cheat#ubuntu-guest-setup
+'''
+    },
+    default_args={'docker': True},
+)
+common.add_build_arguments(parser)
+args = common.setup(parser)
+container_name = 'lkmc-guest'
+#common.rmrf(common.docker_build_dir)
+if not args.clean:
+    start_time = time.time()
+    target_dir = os.path.join('/root', 'linux-kernel-module-cheat')
+    os.makedirs(common.docker_build_dir, exist_ok=True)
+    containers = subprocess.check_output([
+            'docker',
+            'ps',
+            '-a',
+            '--format', '{{.Names}}',
+    ]).decode()
+    if container_name in containers.split():
+        assert common.run_cmd([
+            'docker',
+            'rm',
+            container_name,
+        ]) == 0
+    assert common.run_cmd([
+        'docker',
+        'create',
+        '--name', container_name,
+        '--net',
+        'host',
+        '-i',
+        '--privileged',
+        '-t',
+        '-w', target_dir,
+        '-v', '{}:{}'.format(common.root_dir, target_dir),
+        'ubuntu:18.04',
+        'bash',
+    ]) == 0
+    assert common.run_cmd([
+        'docker',
+        'export',
+        '-o',
+        common.docker_tar_file,
+        container_name,
+    ]) == 0
+    tar = tarfile.open(common.docker_tar_file)
+    tar.extractall(common.docker_tar_dir)
+    tar.close()
+    # sudo not required in theory
+    # https://askubuntu.com/questions/1046828/how-to-run-libguestfs-tools-tools-such-as-virt-make-fs-without-sudo
+    assert common.run_cmd([
+        'virt-make-fs',
+        '--format', 'raw',
+        '--size', '+1G',
+        '--type', 'ext2',
+        common.docker_tar_dir,
+        common.docker_rootfs_raw_file,
+    ]) == 0
+    common.raw_to_qcow2(prebuilt=True)
+    end_time = time.time()
+    common.print_time(end_time - start_time)