#!/usr/bin/python3
"""
Assemble a tar archive
Assembles the tree into a tar archive named `filename`.
Uses the buildhost's `tar` command, like: `tar -cf $FILENAME -C $TREE`
If the `compression` option is given, the archive will be compressed by passing
the `--{compression}` option to `tar`. (This option is non-standard and might
not work for anything other than GNU tar.)
Known options for `compression`: "bzip2", "xz", "lzip", "lzma", "lzop", "gzip".
Note that using `compression` does not add an extension to `filename`, so the
caller is responsible for making sure that `compression` and `filename` match.
Buildhost commands used: `tar` and any named `compression` program.
"""
import json
import subprocess
import sys
SCHEMA = """
"additionalProperties": false,
"required": ["filename"],
"properties": {
"filename": {
"description": "Filename for tar archive",
"type": "string"
},
"compression": {
"description": "Name of compression program",
"type": "string",
"enum": ["bzip2", "xz", "lzip", "lzma", "lzop", "gzip"]
}
}
"""
def main(tree, output_dir, options):
filename = options["filename"]
compression = options.get("compression")
extra_args = []
if compression is not None:
if compression not in {"bzip2", "xz", "lzip", "lzma", "lzop", "gzip"}:
return 1
extra_args.append(f"--{compression}")
# Set environment variables for the tar operation.
tar_env = {
# Speed up xz by allowing it to use all CPU cores for compression.
"XZ_OPT": "--threads 0"
}
# Set up the tar command.
tar_cmd = [
"tar",
*extra_args,
"-cf", f"{output_dir}/{filename}",
"-C", tree,
"."
]
# Make a tarball of the tree.
subprocess.run(
tar_cmd,
stdout=subprocess.DEVNULL,
check=True,
env=tar_env
)
return 0
if __name__ == '__main__':
args = json.load(sys.stdin)
r = main(args["tree"], args["output_dir"], args["options"])
sys.exit(r)