Struct MemberLifeline 

pub struct MemberLifeline { /* private fields */ }

The launcher’s side of one member’s lifeline: the write end it holds for the formation’s life, and the read end until the member has been spawned with it.

Dropping it closes whatever it still holds, so a launcher that is gone has closed every lifeline.

Implementations

impl MemberLifeline

pub fn new() -> Result<Self>

A new pipe, both ends FD_CLOEXEC, the read end numbered 3 or above.

Where pipe2 is missing the flag is set after pipe returns, so a process that spawns from other threads must create every lifeline before its first spawn.

pub fn hand_to(&self, command: &mut Command)

Give the member command will start its read end: set FORMATION_LIFELINE_ENV and register a pre_exec that clears FD_CLOEXEC on that one descriptor in the child.

Register it after any fd-hygiene pre_exec, which marks every inherited descriptor close-on-exec; pre_exec closures run in registration order. The child never gets the write end, which stays close-on-exec. Does nothing once Self::spawned has run.

pub fn spawned(&mut self)

Close the launcher’s copy of the read end once the member holds its own, so the member is the read end’s only holder.

pub fn close(&mut self)

Close the write end: the member reads EOF, which tells it the formation has ended. Idempotent.

pub fn write_fd(&self) -> Option<RawFd>

The write end’s descriptor number, while it is open.

Trait Implementations

impl Debug for MemberLifeline

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.