debian-forge/osbuild
Lars Karlitski da121beda1 osbuild: factor out BuildContainer
As start of a public API for osbuild.
2019-06-12 19:40:59 +02:00

136 lines
5.1 KiB
Python
Executable file

#!/usr/bin/python3
import argparse
import json
import os
import subprocess
import sys
import tempfile
RESET = "\033[0m"
BOLD = "\033[1m"
RED = "\033[31m"
class BuildContainer:
def __init__(self, path=os.getcwd()):
self.buildroot = tempfile.mkdtemp(prefix="osbuild-buildroot-", dir=path)
self.buildroot_mounted = False
self.tree = tempfile.mkdtemp(prefix="osbuild-tree-", dir=path)
self.tree_mounted = False
try:
subprocess.run(["mount", "-o", "bind,ro", "/", self.buildroot], check=True)
self.tree_mounted = True
subprocess.run(["mount", "-t", "tmpfs", "tmpfs", self.tree], check=True)
self.buildroot_mounted = True
except subprocess.CalledProcessError:
self.unmount()
raise
def unmount(self):
if self.tree:
if self.tree_mounted:
subprocess.run(["umount", "--lazy", self.tree], check=True)
os.rmdir(self.tree)
self.tree = None
if self.buildroot:
if self.buildroot_mounted:
subprocess.run(["umount", "--lazy", self.buildroot], check=True)
os.rmdir(self.buildroot)
self.buildroot = None
def __del__(self):
self.unmount()
def __enter__(self):
return self
def __exit__(self, exc_type, exc_value, exc_tb):
self.unmount()
def main(pipeline_path, input_dir, output_dir, sit):
if output_dir and len(os.listdir(output_dir)) != 0:
print()
print(f"{RESET}{BOLD}{RED}Output directory {output_dir} is not empty{RESET}")
return 1
with open(pipeline_path) as f:
pipeline = json.load(f)
with BuildContainer() as container:
for i, stage in enumerate(pipeline["stages"], start=1):
name = stage["name"]
options = stage.get("options", {})
options["tree"] = "/tmp/tree"
# systemd-nspawn silently removes some characters when choosing a
# machine name from the directory name. The only one relevant for
# us is '_', because all other characters used by
# TemporaryDirectory() are allowed. Replace it with 'L's
# (TemporaryDirectory() only uses lower-case characters)
machine_name = os.path.basename(container.buildroot).replace("_", "L")
argv = ["systemd-nspawn",
"--as-pid2",
"--link-journal=no",
"--volatile=yes",
f"--machine={machine_name}",
f"--directory={container.buildroot}",
f"--bind={container.tree}:/tmp/tree",
f"--bind={os.getcwd()}/run-stage:/tmp/run-stage",
f"--bind={os.getcwd()}/stages/{name}:/tmp/stage",
"--bind=/etc/pki"]
# Optionally pass the input dir to the first stage
if input_dir:
options["input_dir"] = "/tmp/input"
argv.append(f"--bind-ro={os.getcwd()}/{input_dir}:/tmp/input")
else:
options["input_dir"] = None
# Pass the tree r/w to all stages but the last one.
# The last stage gets the tree ro and optionally gets an output dir
if i == len(pipeline["stages"]) and output_dir:
options["output_dir"] = "/tmp/output"
argv.append(f"--bind={os.getcwd()}/{output_dir}:/tmp/output")
argv.append("/tmp/run-stage")
if sit:
argv.append("--sit")
argv.append("/tmp/stage")
options_str = json.dumps(options, indent=2)
print()
print(f"{RESET}{BOLD}{i}. {name}{RESET} {options_str}")
print("Inspect with:")
print(f"\t# nsenter -a --wd=/root -t `machinectl show {machine_name} -p Leader --value`")
print()
try:
subprocess.run(argv, input=options_str, encoding="utf-8", check=True)
except KeyboardInterrupt:
print()
print(f"{RESET}{BOLD}{RED}Aborted{RESET}")
return 130
except subprocess.CalledProcessError as error:
print()
print(f"{RESET}{BOLD}{RED}{name} failed with code {error.returncode}{RESET}")
return 1
if __name__ == "__main__":
parser = argparse.ArgumentParser(description="Build operating system images")
parser.add_argument("pipeline_path", metavar="PIPELINE",
help="json file containing the pipeline that should be built")
parser.add_argument("--input", dest="input_dir", metavar="DIRECTORY",
help="provide the contents of DIRECTORY to the first stage")
parser.add_argument("--output", dest="output_dir", metavar="DIRECTORY",
help="provide the empty DIRECTORY as output argument to the last stage")
parser.add_argument("--sit", action="store_true",
help="keep the build environment up when a stage failed")
args = parser.parse_args()
sys.exit(main(**vars(args)))