comparison rust/chg/src/locator.rs @ 44671:bb936e25a84a

rust-chg: spawn server process if not running

This is the minimal reimplementation of gethgcmd(), execcmdserver(),
retryconnectcmdserver(), and connectcmdserver() in chg.c.

No config validation is implemented yet. And some Py3 workarounds would
be missing as this is the code I wrote in 2018.

Differential Revision: https://phab.mercurial-scm.org/D8360

44670:cf144f50f413

// This software may be used and distributed according to the terms of the
// GNU General Public License version 2 or any later version.

//! Utility for locating command-server process.

use std::env;
use std::ffi::{OsStr, OsString};
use std::fs::{self, DirBuilder};
use std::io;
use std::os::unix::ffi::{OsStrExt, OsStringExt};
use std::os::unix::fs::{DirBuilderExt, MetadataExt};
use std::path::{Path, PathBuf};
use std::process;
use std::time::Duration;

use super::procutil;

/// Helper to connect to and spawn a server process.
#[derive(Clone, Debug)]

        let mut buf = Vec::with_capacity(src.len() + 6); // "{src}.{pid}".len()
        buf.extend_from_slice(src);
        buf.extend_from_slice(format!(".{}", self.process_id).as_bytes());
        OsString::from_vec(buf).into()
    }
}

/// Determines the server socket to connect to.
///
/// If no `$CHGSOCKNAME` is specified, the socket directory will be created
/// as necessary.
pub fn prepare_server_socket_path() -> io::Result<PathBuf> {
    if let Some(s) = env::var_os("CHGSOCKNAME") {
        Ok(PathBuf::from(s))
    } else {
        let mut path = default_server_socket_dir();
        create_secure_dir(&path)?;

44671:bb936e25a84a

// This software may be used and distributed according to the terms of the
// GNU General Public License version 2 or any later version.

//! Utility for locating command-server process.

use futures::future::{self, Either, Loop};
use std::env;
use std::ffi::{OsStr, OsString};
use std::fs::{self, DirBuilder};
use std::io;
use std::os::unix::ffi::{OsStrExt, OsStringExt};
use std::os::unix::fs::{DirBuilderExt, MetadataExt};
use std::path::{Path, PathBuf};
use std::process::{self, Command};
use std::time::Duration;
use tokio::prelude::*;
use tokio_hglib::UnixClient;
use tokio_process::{Child, CommandExt};
use tokio_timer;

use super::procutil;

/// Helper to connect to and spawn a server process.
#[derive(Clone, Debug)]

        let mut buf = Vec::with_capacity(src.len() + 6); // "{src}.{pid}".len()
        buf.extend_from_slice(src);
        buf.extend_from_slice(format!(".{}", self.process_id).as_bytes());
        OsString::from_vec(buf).into()
    }

    /// Connects to the server.
    ///
    /// The server process will be spawned if not running.
    pub fn connect(self) -> impl Future<Item = (Self, UnixClient), Error = io::Error> {
        self.try_connect()
    }

    /// Tries to connect to the existing server, or spawns new if not running.
    fn try_connect(self) -> impl Future<Item = (Self, UnixClient), Error = io::Error> {
        debug!("try connect to {}", self.base_sock_path.display());
        UnixClient::connect(self.base_sock_path.clone()).then(|res| match res {
            Ok(client) => Either::A(future::ok((self, client))),
            Err(_) => Either::B(self.spawn_connect()),
        })
    }

    /// Spawns new server process and connects to it.
    ///
    /// The server will be spawned at the current working directory, then
    /// chdir to "/", so that the server will load configs from the target
    /// repository.
    fn spawn_connect(self) -> impl Future<Item = (Self, UnixClient), Error = io::Error> {
        let sock_path = self.temp_sock_path();
        debug!("start cmdserver at {}", sock_path.display());
        Command::new(&self.hg_command)
            .arg("serve")
            .arg("--cmdserver")
            .arg("chgunix")
            .arg("--address")
            .arg(&sock_path)
            .arg("--daemon-postexec")
            .arg("chdir:/")
            .current_dir(&self.current_dir)
            .env_clear()
            .envs(self.env_vars.iter().cloned())
            .env("CHGINTERNALMARK", "")
            .spawn_async()
            .into_future()
            .and_then(|server| self.connect_spawned(server, sock_path))
            .and_then(|(loc, client, sock_path)| {
                debug!(
                    "rename {} to {}",
                    sock_path.display(),
                    loc.base_sock_path.display()
                );
                fs::rename(&sock_path, &loc.base_sock_path)?;
                Ok((loc, client))
            })
    }

    /// Tries to connect to the just spawned server repeatedly until timeout
    /// exceeded.
    fn connect_spawned(
        self,
        server: Child,
        sock_path: PathBuf,
    ) -> impl Future<Item = (Self, UnixClient, PathBuf), Error = io::Error> {
        debug!("try connect to {} repeatedly", sock_path.display());
        let connect = future::loop_fn(sock_path, |sock_path| {
            UnixClient::connect(sock_path.clone()).then(|res| {
                match res {
                    Ok(client) => Either::A(future::ok(Loop::Break((client, sock_path)))),
                    Err(_) => {
                        // try again with slight delay
                        let fut = tokio_timer::sleep(Duration::from_millis(10))
                            .map(|()| Loop::Continue(sock_path))
                            .map_err(|err| io::Error::new(io::ErrorKind::Other, err));
                        Either::B(fut)
                    }
                }
            })
        });

        // waits for either connection established or server failed to start
        connect
            .select2(server)
            .map_err(|res| res.split().0)
            .timeout(self.timeout)
            .map_err(|err| {
                err.into_inner().unwrap_or_else(|| {
                    io::Error::new(
                        io::ErrorKind::TimedOut,
                        "timed out while connecting to server",
                    )
                })
            })
            .and_then(|res| {
                match res {
                    Either::A(((client, sock_path), server)) => {
                        server.forget(); // continue to run in background
                        Ok((self, client, sock_path))
                    }
                    Either::B((st, _)) => Err(io::Error::new(
                        io::ErrorKind::Other,
                        format!("server exited too early: {}", st),
                    )),
                }
            })
    }
}

/// Determines the server socket to connect to.
///
/// If no `$CHGSOCKNAME` is specified, the socket directory will be created
/// as necessary.
fn prepare_server_socket_path() -> io::Result<PathBuf> {
    if let Some(s) = env::var_os("CHGSOCKNAME") {
        Ok(PathBuf::from(s))
    } else {
        let mut path = default_server_socket_dir();
        create_secure_dir(&path)?;