# -*- Mode:Python; indent-tabs-mode:nil; tab-width:4 -*-
#
# Copyright 2021 Canonical Ltd.
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU Lesser General Public
# License version 3 as published by the Free Software Foundation.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
# Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
"""The snap source handler."""
import os
import shutil
import tempfile
from pathlib import Path
from typing import Optional, cast
import yaml
from overrides import overrides
from craft_parts.dirs import ProjectDirs
from craft_parts.utils import file_utils
from . import errors
from .base import FileSourceHandler
[docs]class SnapSource(FileSourceHandler):
"""Handles downloading and extractions for a snap source.
On provision, the meta directory is renamed to meta.<snap-name> and, if present,
the same applies for the snap directory which shall be renamed to
snap.<snap-name>.
"""
def __init__(
self,
source: str,
part_src_dir: Path,
*,
cache_dir: Path,
project_dirs: ProjectDirs,
source_tag: Optional[str] = None,
source_commit: Optional[str] = None,
source_branch: Optional[str] = None,
source_depth: Optional[int] = None,
source_checksum: Optional[str] = None,
**kwargs,
) -> None:
super().__init__(
source,
part_src_dir,
cache_dir=cache_dir,
source_tag=source_tag,
source_commit=source_commit,
source_branch=source_branch,
source_depth=source_depth,
source_checksum=source_checksum,
project_dirs=project_dirs,
command="unsquashfs",
**kwargs,
)
if source_tag:
raise errors.InvalidSourceOption(source_type="snap", option="source-tag")
if source_commit:
raise errors.InvalidSourceOption(source_type="snap", option="source-commit")
if source_branch:
raise errors.InvalidSourceOption(source_type="snap", option="source-branch")
if source_depth:
raise errors.InvalidSourceOption(source_type="snap", option="source-depth")
[docs] @overrides
def provision(
self,
dst: Path,
keep: bool = False,
src: Optional[Path] = None,
) -> None:
"""Provision the snap source.
:param dst: The destination directory to provision to.
:param keep: Whether to keep the snap after provisioning is complete.
:param src: Force a new source to use for extraction.
raises errors.InvalidSnap: If trying to provision an invalid snap.
"""
if src:
snap_file = src
else:
snap_file = self.part_src_dir / os.path.basename(self.source)
snap_file = snap_file.resolve()
# unsquashfs [options] filesystem [directories or files to extract]
# options:
# -force: if file already exists then overwrite
# -dest <pathname>: unsquash to <pathname>
with tempfile.TemporaryDirectory(prefix=str(snap_file.parent)) as temp_dir:
extract_command = [
"unsquashfs",
"-force",
"-dest",
temp_dir,
snap_file,
]
self._run_output(extract_command)
snap_name = _get_snap_name(snap_file.name, temp_dir)
# Rename meta and snap dirs from the snap
rename_paths = (os.path.join(temp_dir, d) for d in ["meta", "snap"])
rename_paths = (d for d in rename_paths if os.path.exists(d))
for rename in rename_paths:
shutil.move(rename, f"{rename}.{snap_name}")
file_utils.link_or_copy_tree(
source_tree=temp_dir, destination_tree=str(dst)
)
if not keep:
os.remove(snap_file)
def _get_snap_name(snap: str, snap_dir: str) -> str:
"""Obtain the snap name from the snap details file.
:param snap: The snap package file.
:param snap_dir: The location of the unsquashed snap contents.
:return: The snap name.
"""
try:
with open(os.path.join(snap_dir, "meta", "snap.yaml")) as snap_yaml:
return cast(str, yaml.safe_load(snap_yaml)["name"])
except (FileNotFoundError, KeyError) as snap_error:
raise errors.InvalidSnapPackage(snap) from snap_error
