import subprocess
from typing import Iterator


def stream_instance_logs(name: str, *, lines: int = 200, follow: bool = True) -> Iterator[str]:
    command = [
        "journalctl",
        "--user",
        "-u",
        f"l4d2@{name}.service",
        "-n",
        str(lines),
        "-o",
        "cat",
    ]
    if follow:
        command.append("-f")

    proc = subprocess.Popen(
        command,
        stdout=subprocess.PIPE,
        stderr=subprocess.PIPE,
        text=True,
        bufsize=1,
    )
    try:
        if proc.stdout is None:
            return
        for raw in iter(proc.stdout.readline, ""):
            yield raw.rstrip("\n")
    finally:
        if proc.poll() is None:
            proc.terminate()
            proc.wait(timeout=2)