plesty.server.services.launch

Detached process launch: no zombies, and an exit code every process can read.

Several plesty-server processes look at the same servers and jobs — the CLI, the agent, fleet run, the GUI. A child that its parent never reaps is a zombie: kill(pid, 0) still succeeds, so a different process takes it for alive and waits a full stop escalation for nothing. And a plain detached child loses its exit code for everyone but its parent.

So nothing here is a direct child. launch() spawns a small waiter (python -m plesty.server.services.launch) that detaches itself (plesty.server.host.detach()), starts the real command with its output appended to the log, forwards the interrupt it receives, waits, and writes the exit code to exit_file. Callers track the waiter’s pid: alive means the command runs; the exit file appears when it is over.

Functions

stop_file(→ pathlib.Path)	The file that asks the waiter of exit_file to stop its command.
launch(→ int)	Start command detached; return the pid of the waiter that owns it.
read_exit(→ int | None)	The exit code recorded in exit_file, or None while it does not exist.
_wait(→ int)	The waiter: run the command, forward the interrupt, record the exit code.
_write_exit(→ None)
_report_pid(→ None)
main(→ int)	Entry point of the waiter (spec as JSON on stdin).

Module Contents

plesty.server.services.launch.stop_file(exit_file: str | os.PathLike[str]) → pathlib.Path

The file that asks the waiter of exit_file to stop its command.

Alongside the exit file, so anything that knows where a command reports its end also knows how to ask it to end (see plesty.server.host.request_stop()).

Parameters:

exit_file (str | os.PathLike[str])

Return type:

pathlib.Path

plesty.server.services.launch.launch(command: collections.abc.Sequence[str], cwd: str | os.PathLike[str], env: collections.abc.Mapping[str, str], log: str | os.PathLike[str], exit_file: str | os.PathLike[str], banner: str = '') → int

Start command detached; return the pid of the waiter that owns it.

Parameters:

• command (collections.abc.Sequence[str]) – The command line.

• cwd (str | os.PathLike[str]) – Working directory.

• env (collections.abc.Mapping[str, str]) – Full environment for the command.

• log (str | os.PathLike[str]) – File its stdout+stderr are appended to.

• exit_file (str | os.PathLike[str]) – File the exit code is written to when it ends (removed first, so its presence means “finished”).

• banner (str) – A line written to the log before the command starts.

Raises:

• OSError – When the waiter itself cannot be started.

• RuntimeError – When the waiter did not report a pid.

Return type:

int

plesty.server.services.launch.read_exit(exit_file: str | os.PathLike[str]) → int | None

The exit code recorded in exit_file, or None while it does not exist.

Parameters:

exit_file (str | os.PathLike[str])

Return type:

int | None

plesty.server.services.launch._wait(spec: dict[str, Any]) → int

The waiter: run the command, forward the interrupt, record the exit code.

Parameters:

spec (dict[str, Any])

Return type:

int

plesty.server.services.launch._write_exit(exit_file: str, code: int) → None

Parameters:

• exit_file (str)

• code (int)

Return type:

None

plesty.server.services.launch._report_pid(pid: int) → None

Parameters:

pid (int)

Return type:

None

plesty.server.services.launch.main() → int

Entry point of the waiter (spec as JSON on stdin).

Reached as python -m plesty.server.services.launch from a source checkout and as plesty-server _launch from a bundle.

Return type:

int