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#!/usr/bin/python3
import argparse
import logging
import os
import shutil
import subprocess
import sys
import tarfile
import tempfile
import yaml
MAX_CACHE_SIZE = 1024**3
OVMF_FD = "/usr/share/ovmf/OVMF.fd"
OVMF_VARS = "/usr/share/OVMF/OVMF_VARS.fd"
class BuildSpec:
def __init__(self, filename):
with open(filename) as f:
o = yaml.safe_load(f)
self.image = os.path.expanduser(o["image"])
self.src = os.path.expanduser(o.get("src", "."))
if "cache" in o:
self.cache = os.path.expanduser(o["cache"])
else:
self.cache = None
if "dependencies" in o:
self.dependencies = os.path.expanduser(o["dependencies"])
else:
self.dependencies = None
if "artifact" in o:
self.artifact = os.path.expanduser(o["artifact"])
else:
self.artifact = None
def parse_args():
p = argparse.ArgumentParser()
p.add_argument("--verbose", action="store_true")
p.add_argument("--log", required=True)
p.add_argument("build_spec")
return p.parse_args()
def extract_tar_from_tar(filename, output):
N = 1024
BLOCK = 10 * 1024
with open(filename, "rb") as f:
tar = tarfile.open(fileobj=f, mode="r:")
while True:
info = tar.next()
if info is None:
break
# We've read to the end of the final tar file entry.
num_bytes = tar.fileobj.tell()
with open(output, "wb") as o:
# Copy first num_bytes of input file to output file.
f.seek(0)
n = 0
while n < num_bytes:
data = f.read(N)
if data is None:
break
o.write(data)
n += len(data)
# Pad output file with zeroes until next block border.
while (n % BLOCK) != 0:
o.write(b"\0")
n += 1
def main():
args = parse_args()
if args.verbose:
level = logging.DEBUG
else:
level = logging.WARNING
logging.basicConfig(
level=level, stream=sys.stdout, format="%(levelname)s %(message)s"
)
logging.debug(f"args: {args}")
try:
logging.debug(f"loading build spec from {args.build_spec}")
build = BuildSpec(args.build_spec)
logging.debug(f"build: {build}")
tmp = tempfile.mkdtemp()
logging.debug(f"created {tmp}")
image = os.path.join(tmp, "vm.qcow2")
output_drive = os.path.join(tmp, "artifacts.tar")
src_tar = os.path.join(tmp, "src.tar")
vars = os.path.join(tmp, "vars.fd")
logging.info(f"copying {build.image} to {image}")
shutil.copyfile(build.image, image)
logging.info(f"copying {OVMF_VARS}")
shutil.copyfile(OVMF_FD, vars)
logging.info(f"create tar of source tree {build.src}")
subprocess.run(["tar", "-cf", src_tar, "-C", build.src, "."], check=True)
logging.info(f"create output drive {output_drive}")
subprocess.run(
["qemu-img", "create", "-q", "-f", "raw", output_drive, "1G"], check=True
)
cache_drive = os.path.join(tmp, "cache.tar")
logging.info(f"using {cache_drive} as cache drive")
tar = tarfile.open(name=cache_drive, mode="w:")
if build.cache is None:
tar.close()
else:
# Tar up the cache directory.
tar.add(build.cache, arcname=".")
tar.close()
# Make the tar the max size.
length = os.path.getsize(cache_drive)
if length < MAX_CACHE_SIZE:
os.truncate(cache_drive, MAX_CACHE_SIZE)
else:
logging.info(
"cache drive {cache_drive} is larger than max allowed, oh well"
)
deps_drive = os.path.join(tmp, "deps.tar")
logging.info(f"using {deps_drive} as the dependencies drive")
tar = tarfile.open(name=deps_drive, mode="w:")
if build.dependencies is None:
tar.close()
else:
# Tar up the dependencies directory.
tar.add(build.dependencies, arcname=".")
tar.close()
logging.info("run build in VM")
argv = [
"kvm",
"-m",
"16384",
"-smp",
"cpus=4",
"-drive",
f"if=pflash,format=raw,unit=0,file={OVMF_FD},readonly=on",
"-drive",
f"if=pflash,format=raw,unit=1,file={vars}",
"-drive",
f"format=qcow2,if=virtio,file={image}",
"-drive",
f"format=raw,if=virtio,file={src_tar},readonly=on",
"-drive",
f"format=raw,if=virtio,file={output_drive}",
"-drive",
f"format=raw,if=virtio,file={cache_drive}",
"-drive",
f"format=raw,if=virtio,file={deps_drive},readonly=on",
"-nodefaults",
"-display",
"none",
"-chardev",
"stdio,id=serial0",
"-serial",
"chardev:serial0",
]
logging.debug(f"run: {argv}")
with open(args.log, "wb") as f:
p = subprocess.run(argv, stdout=f)
if p.returncode != 0:
sys.stderr.write(p.stderr.decode())
raise Exception("qemu-system failed")
if build.artifact is not None:
logging.info("extract artifacts, if any")
extract_tar_from_tar(output_drive, build.artifact)
if build.cache is not None:
logging.info(f"extract potentially updated cache from {cache_drive}")
subprocess.run(
["tar", "-xf", cache_drive, "-C", build.cache],
check=True,
)
logging.info("Build finished")
except Exception as e:
sys.stderr.write(f"{e}\n")
sys.exit(1)
finally:
logging.debug(f"removing {tmp}")
shutil.rmtree(tmp)
main()
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