def _extract_jex_file_if_exists()

in shim/shim.py [0:0]

• 36 lines of code
• 9 McCabe index (conditional complexity)

def _extract_jex_file_if_exists(path: Path, target: str, build_directory: Path) -> Path:
    jex_extract_directory: Path = Path(build_directory) / "jex"

    def run_unzip_command(command: List[str]) -> Path:
        output = subprocess.run(command, stderr=subprocess.PIPE)
        if output.returncode != 0:
            stderr = output.stderr.decode()
            if (
                command[0] == "unzip"
                and output.returncode == 1
                and "extra bytes at beginning or within zipfile" in stderr
            ):
                # This warning is fine to ignore, because *.jar files have been properly extracted
                LOG.warning(f"`unzip` warning: {stderr}")
            else:
                command_string = " ".join(command)
                raise ExtractJexException(
                    f"Unable to extract binary file `{path}` with command `{command_string}`:\n{stderr}"
                )

        jar_file_path = jex_extract_directory / (
            target.rsplit(":", maxsplit=1)[1] + ".jar"
        )
        if jar_file_path.exists():
            return jar_file_path
        else:
            raise ClientError(
                f"Could not find jar file `{path}` in `{jex_extract_directory}`."
            )

    # If the target is java_binary, then the output is a JEX file
    if path.suffix != ".jex":
        return path

    # Try to extract *.jex files with various unzip tools, until one of them succeeds. See D22579374 for why doing this
    try:
        return run_unzip_command(
            ["unsquashfs", "-d", str(jex_extract_directory), "-o", "4096", str(path)]
        )
    except ExtractJexException:
        LOG.warning(f"Running `unsquashfs` on file `{path}` failed.")
        LOG.warning(f"Trying to extract file `{path}` with `unzip`.")
        return run_unzip_command(["unzip", "-d", str(jex_extract_directory), str(path)])