[virt-tools-list] [virt-bootstrap] [PATCH 6/9] sources: Add support for virt-builder

[Radostin Stoyanov]

Create container root file system from VM image build with virt-builder
---
 src/virtBootstrap/sources.py        | 100 +++++++++++++++++++++++++++++++++++-
 src/virtBootstrap/utils.py          |   9 ++++
 src/virtBootstrap/virt_bootstrap.py |   2 +-
 3 files changed, 109 insertions(+), 2 deletions(-)

diff --git a/src/virtBootstrap/sources.py b/src/virtBootstrap/sources.py
index 673e68c..3f06f96 100644
--- a/src/virtBootstrap/sources.py
+++ b/src/virtBootstrap/sources.py
@@ -25,7 +25,7 @@ import shutil
 import getpass
 import os
 import logging
-from subprocess import CalledProcessError, PIPE, Popen
+from subprocess import CalledProcessError, PIPE, Popen, check_call
 
 from virtBootstrap import utils
 
@@ -328,3 +328,101 @@ class DockerSource(object):
             # Clean up
             if self.no_cache and self.images_dir != utils.DEFAULT_IMG_DIR:
                 shutil.rmtree(self.images_dir)
+
+
+class VirtBuilderSource(object):
+    """
+    Extract root file system from image build with virt-builder.
+    """
+    def __init__(self, **kwargs):
+        """
+        Create container rootfs by building VM from virt-builder template
+        and extract the rootfs.
+
+        @param uri: Template name
+        @param fmt: Format used to store the output [dir, qcow2]
+        @param progress: Instance of the progress module
+        """
+        # Parsed URIs:
+        # - "virt-builder:///<template>"
+        # - "virt-builder://<template>"
+        # - "virt-builder:/<template>"
+        self.template = kwargs['uri'].netloc or kwargs['uri'].path[1:]
+        self.output_format = kwargs.get('fmt', utils.DEFAULT_OUTPUT_FORMAT)
+        self.progress = kwargs['progress'].update_progress
+
+    def build_image(self, output_file):
+        """
+        Build VM from virt-builder template
+        """
+        cmd = ['virt-builder', self.template,
+               '-o', output_file,
+               '--no-network',
+               '--delete', '/dev/*',
+               '--delete', '/boot/*',
+               # Comment out every line in fstab
+               '--edit', '/etc/fstab:s/^/#/']
+        check_call(cmd)
+
+    def unpack(self, dest):
+        """
+        Build image and extract root file system
+
+        @param dest: Directory path where output files will be stored.
+        """
+
+        tmp_dir = utils.get_image_dir(no_cache=True)
+        tmp_image_file = os.path.join(tmp_dir, self.template + '.img')
+
+        try:
+            if self.output_format == 'dir':
+
+                self.progress("Building image", value=0, logger=logger)
+                self.build_image(tmp_image_file)
+
+                self.progress("Extracting file system",
+                              value=50, logger=logger)
+                utils.execute(['virt-copy-out',
+                               '-a', tmp_image_file, '/', dest])
+
+                self.progress("Extraction completed successfully!",
+                              value=100, logger=logger)
+                logger.info("Files are stored in: %s", dest)
+
+            elif self.output_format == 'qcow2':
+                # Use templete name as name for the output image
+                image_file = os.path.join(dest, self.template + '.qcow2')
+                utils.show_error_if_file_exits(image_file)
+
+                # Create temporary directory to extract file system
+                tmp_tar_file = os.path.join(tmp_dir, 'filesystem.tar')
+
+                self.progress("Building image", value=0, logger=logger)
+                self.build_image(tmp_image_file)
+
+                self.progress("Extracting file system", value=33,
+                              logger=logger)
+                utils.execute(['virt-tar-out',
+                               '-a', tmp_image_file, '/', tmp_tar_file])
+
+                self.progress("Creating qcow2 image with single partition",
+                              value=66, logger=logger)
+                utils.execute(['virt-make-fs',
+                               '--type=ext3',
+                               '--format=qcow2',
+                               '--size=+200M',
+                               tmp_tar_file, image_file])
+
+                self.progress("Extraction completed successfully!", value=100,
+                              logger=logger)
+                logger.info("Image is stored in: %s", image_file)
+
+            else:
+                raise Exception("Unknown format:" + self.output_format)
+
+        except Exception:
+            raise
+
+        finally:
+            # Clean up
+            shutil.rmtree(tmp_dir)
diff --git a/src/virtBootstrap/utils.py b/src/virtBootstrap/utils.py
index aadc393..499cc0b 100644
--- a/src/virtBootstrap/utils.py
+++ b/src/virtBootstrap/utils.py
@@ -429,3 +429,12 @@ def write_progress(prog):
     # Write message to console
     sys.stdout.write(msg)
     sys.stdout.flush()
+
+
+def show_error_if_file_exits(path):
+    """
+    Show error message if path exist and exit
+    """
+    if os.path.exists(path):
+        logger.error("File already exist '%s'", path)
+        sys.exit(1)
diff --git a/src/virtBootstrap/virt_bootstrap.py b/src/virtBootstrap/virt_bootstrap.py
index 029cee2..b8c3e29 100755
--- a/src/virtBootstrap/virt_bootstrap.py
+++ b/src/virtBootstrap/virt_bootstrap.py
@@ -62,7 +62,7 @@ def get_source(source_type):
     Get object which match the source type
     """
     try:
-        class_name = "%sSource" % source_type.capitalize()
+        class_name = "%sSource" % source_type.title().replace('-', '')
         clazz = getattr(sources, class_name)
         return clazz
     except Exception:
-- 
2.9.4