smol-rs
/
async-process
mirror of https://github.com/smol-rs/async-process
1
0
Fork 0
Code Issues Projects Releases Wiki Activity
async-process/src/lib.rs

1134 lines
34 KiB
Rust
Raw Blame History

//! Async interface for working with processes.
//!
//! This crate is an async version of [`std::process`].
//!
//! # Implementation
//!
//! A background thread named "async-process" is lazily created on first use, which waits for
//! spawned child processes to exit and then calls the `wait()` syscall to clean up the "zombie"
//! processes. This is unlike the `process` API in the standard library, where dropping a running
//! `Child` leaks its resources.
//!
//! This crate uses [`async-io`] for async I/O on Unix-like systems and [`blocking`] for async I/O
//! on Windows.
//!
//! [`async-io`]: https://docs.rs/async-io
//! [`blocking`]: https://docs.rs/blocking
//!
//! # Examples
//!
//! Spawn a process and collect its output:
//!
//! ```no_run
//! # futures_lite::future::block_on(async {
//! use async_process::Command;
//!
//! let out = Command::new("echo").arg("hello").arg("world").output().await?;
//! assert_eq!(out.stdout, b"hello world\n");
//! # std::io::Result::Ok(()) });
//! ```
//!
//! Read the output line-by-line as it gets produced:
//!
//! ```no_run
//! # futures_lite::future::block_on(async {
//! use async_process::{Command, Stdio};
//! use futures_lite::{io::BufReader, prelude::*};
//!
//! let mut child = Command::new("find")
//! .arg(".")
//! .stdout(Stdio::piped())
//! .spawn()?;
//!
//! let mut lines = BufReader::new(child.stdout.take().unwrap()).lines();
//!
//! while let Some(line) = lines.next().await {
//! println!("{}", line?);
//! }
//! # std::io::Result::Ok(()) });
//! ```
#![warn(missing_docs, missing_debug_implementations, rust_2018_idioms)]
use std::ffi::OsStr;
use std::fmt;
use std::path::Path;
use std::pin::Pin;
use std::sync::{Arc, Mutex};
use std::task::{Context, Poll};
use std::thread;
#[cfg(unix)]
use async_io::Async;
#[cfg(all(not(async_process_no_io_safety), unix))]
use std::convert::{TryFrom, TryInto};
#[cfg(all(not(async_process_no_io_safety), unix))]
use std::os::unix::io::{AsFd, BorrowedFd, OwnedFd};
#[cfg(unix)]
use std::os::unix::io::{AsRawFd, RawFd};
#[cfg(windows)]
use blocking::Unblock;
use async_lock::OnceCell;
use event_listener::Event;
use futures_lite::{future, io, prelude::*};
#[doc(no_inline)]
pub use std::process::{ExitStatus, Output, Stdio};
#[cfg(unix)]
pub mod unix;
#[cfg(windows)]
pub mod windows;
mod sealed {
pub trait Sealed {}
}
/// An event delivered every time the SIGCHLD signal occurs.
static SIGCHLD: Event = Event::new();
/// A guard that can kill child processes, or push them into the zombie list.
struct ChildGuard {
inner: Option<std::process::Child>,
reap_on_drop: bool,
kill_on_drop: bool,
}
impl ChildGuard {
fn get_mut(&mut self) -> &mut std::process::Child {
self.inner.as_mut().unwrap()
}
}
/// A spawned child process.
///
/// The process can be in running or exited state. Use [`status()`][`Child::status()`] or
/// [`output()`][`Child::output()`] to wait for it to exit.
///
/// If the [`Child`] is dropped, the process keeps running in the background.
///
/// # Examples
///
/// Spawn a process and wait for it to complete:
///
/// ```no_run
/// # futures_lite::future::block_on(async {
/// use async_process::Command;
///
/// Command::new("cp").arg("a.txt").arg("b.txt").status().await?;
/// # std::io::Result::Ok(()) });
/// ```
pub struct Child {
/// The handle for writing to the child's standard input (stdin), if it has been captured.
pub stdin: Option<ChildStdin>,
/// The handle for reading from the child's standard output (stdout), if it has been captured.
pub stdout: Option<ChildStdout>,
/// The handle for reading from the child's standard error (stderr), if it has been captured.
pub stderr: Option<ChildStderr>,
/// The inner child process handle.
child: Arc<Mutex<ChildGuard>>,
}
impl Child {
/// Wraps the inner child process handle and registers it in the global process list.
///
/// The "async-process" thread waits for processes in the global list and cleans up the
/// resources when they exit.
fn new(cmd: &mut Command) -> io::Result<Child> {
let mut child = cmd.inner.spawn()?;
// Convert sync I/O types into async I/O types.
let stdin = child.stdin.take().map(wrap).transpose()?.map(ChildStdin);
let stdout = child.stdout.take().map(wrap).transpose()?.map(ChildStdout);
let stderr = child.stderr.take().map(wrap).transpose()?.map(ChildStderr);
cfg_if::cfg_if! {
if #[cfg(windows)] {
use std::ffi::c_void;
use std::os::windows::io::AsRawHandle;
use std::sync::mpsc;
use windows_sys::Win32::{
System::{
Threading::{RegisterWaitForSingleObject, WT_EXECUTEINWAITTHREAD, WT_EXECUTEONLYONCE},
WindowsProgramming::INFINITE,
},
Foundation::{BOOLEAN, HANDLE},
};
// This channel is used to simulate SIGCHLD on Windows.
fn callback_channel() -> (&'static mpsc::SyncSender<()>, &'static Mutex<mpsc::Receiver<()>>) {
static CALLBACK: OnceCell<(mpsc::SyncSender<()>, Mutex<mpsc::Receiver<()>>)> =
OnceCell::new();
let (s, r) = CALLBACK.get_or_init_blocking(|| {
let (s, r) = mpsc::sync_channel(1);
(s, Mutex::new(r))
});
(s, r)
}
// Called when a child exits.
unsafe extern "system" fn callback(_: *mut c_void, _: BOOLEAN) {
callback_channel().0.try_send(()).ok();
}
// Register this child process to invoke `callback` on exit.
let mut wait_object = 0;
let ret = unsafe {
RegisterWaitForSingleObject(
&mut wait_object,
child.as_raw_handle() as HANDLE,
Some(callback),
std::ptr::null_mut(),
INFINITE,
WT_EXECUTEINWAITTHREAD | WT_EXECUTEONLYONCE,
)
};
if ret == 0 {
return Err(io::Error::last_os_error());
}
// Waits for the next SIGCHLD signal.
fn wait_sigchld() {
callback_channel().1.lock().unwrap().recv().ok();
}
// Wraps a sync I/O type into an async I/O type.
fn wrap<T>(io: T) -> io::Result<Unblock<T>> {
Ok(Unblock::new(io))
}
} else if #[cfg(unix)] {
static SIGNALS: OnceCell<Mutex<signal_hook::iterator::Signals>> = OnceCell::new();
// Make sure the signal handler is registered before interacting with the process.
SIGNALS.get_or_init_blocking(|| Mutex::new(
signal_hook::iterator::Signals::new(&[signal_hook::consts::SIGCHLD])
.expect("cannot set signal handler for SIGCHLD"),
));
// Waits for the next SIGCHLD signal.
fn wait_sigchld() {
SIGNALS.get().expect("Signals not registered").lock().unwrap().forever().next();
}
// Wraps a sync I/O type into an async I/O type.
fn wrap<T: std::os::unix::io::AsRawFd>(io: T) -> io::Result<Async<T>> {
Async::new(io)
}
}
}
static ZOMBIES: OnceCell<Mutex<Vec<std::process::Child>>> = OnceCell::new();
// Make sure the thread is started.
ZOMBIES.get_or_init_blocking(|| {
// Start a thread that handles SIGCHLD and notifies tasks when child processes exit.
thread::Builder::new()
.name("async-process".to_string())
.spawn(move || {
loop {
// Wait for the next SIGCHLD signal.
wait_sigchld();
// Notify all listeners waiting on the SIGCHLD event.
SIGCHLD.notify(std::usize::MAX);
// Reap zombie processes.
let mut zombies = ZOMBIES.get().unwrap().lock().unwrap();
let mut i = 0;
while i < zombies.len() {
if let Ok(None) = zombies[i].try_wait() {
i += 1;
} else {
zombies.swap_remove(i);
}
}
}
})
.expect("cannot spawn async-process thread");
Mutex::new(Vec::new())
});
// When the last reference to the child process is dropped, push it into the zombie list.
impl Drop for ChildGuard {
fn drop(&mut self) {
if self.kill_on_drop {
self.get_mut().kill().ok();
}
if self.reap_on_drop {
let mut zombies = ZOMBIES.get().unwrap().lock().unwrap();
if let Ok(None) = self.get_mut().try_wait() {
zombies.push(self.inner.take().unwrap());
}
}
}
}
Ok(Child {
stdin,
stdout,
stderr,
child: Arc::new(Mutex::new(ChildGuard {
inner: Some(child),
reap_on_drop: cmd.reap_on_drop,
kill_on_drop: cmd.kill_on_drop,
})),
})
}
/// Returns the OS-assigned process identifier associated with this child.
///
/// # Examples
///
/// ```no_run
/// # futures_lite::future::block_on(async {
/// use async_process::Command;
///
/// let mut child = Command::new("ls").spawn()?;
/// println!("id: {}", child.id());
/// # std::io::Result::Ok(()) });
/// ```
pub fn id(&self) -> u32 {
self.child.lock().unwrap().get_mut().id()
}
/// Forces the child process to exit.
///
/// If the child has already exited, an [`InvalidInput`] error is returned.
///
/// This is equivalent to sending a SIGKILL on Unix platforms.
///
/// [`InvalidInput`]: `std::io::ErrorKind::InvalidInput`
///
/// # Examples
///
/// ```no_run
/// # futures_lite::future::block_on(async {
/// use async_process::Command;
///
/// let mut child = Command::new("yes").spawn()?;
/// child.kill()?;
/// println!("exit status: {}", child.status().await?);
/// # std::io::Result::Ok(()) });
/// ```
pub fn kill(&mut self) -> io::Result<()> {
self.child.lock().unwrap().get_mut().kill()
}
/// Returns the exit status if the process has exited.
///
/// Unlike [`status()`][`Child::status()`], this method will not drop the stdin handle.
///
/// # Examples
///
/// ```no_run
/// # futures_lite::future::block_on(async {
/// use async_process::Command;
///
/// let mut child = Command::new("ls").spawn()?;
///
/// match child.try_status()? {
/// None => println!("still running"),
/// Some(status) => println!("exited with: {}", status),
/// }
/// # std::io::Result::Ok(()) });
/// ```
pub fn try_status(&mut self) -> io::Result<Option<ExitStatus>> {
self.child.lock().unwrap().get_mut().try_wait()
}
/// Drops the stdin handle and waits for the process to exit.
///
/// Closing the stdin of the process helps avoid deadlocks. It ensures that the process does
/// not block waiting for input from the parent process while the parent waits for the child to
/// exit.
///
/// # Examples
///
/// ```no_run
/// # futures_lite::future::block_on(async {
/// use async_process::{Command, Stdio};
///
/// let mut child = Command::new("cp")
/// .arg("a.txt")
/// .arg("b.txt")
/// .spawn()?;
///
/// println!("exit status: {}", child.status().await?);
/// # std::io::Result::Ok(()) });
/// ```
pub fn status(&mut self) -> impl Future<Output = io::Result<ExitStatus>> {
self.stdin.take();
let child = self.child.clone();
async move {
let mut listener = None;
loop {
if let Some(status) = child.lock().unwrap().get_mut().try_wait()? {
return Ok(status);
}
match listener.take() {
None => listener = Some(SIGCHLD.listen()),
Some(listener) => listener.await,
}
}
}
}
/// Drops the stdin handle and collects the output of the process.
///
/// Closing the stdin of the process helps avoid deadlocks. It ensures that the process does
/// not block waiting for input from the parent process while the parent waits for the child to
/// exit.
///
/// In order to capture the output of the process, [`Command::stdout()`] and
/// [`Command::stderr()`] must be configured with [`Stdio::piped()`].
///
/// # Examples
///
/// ```no_run
/// # futures_lite::future::block_on(async {
/// use async_process::{Command, Stdio};
///
/// let child = Command::new("ls")
/// .stdout(Stdio::piped())
/// .stderr(Stdio::piped())
/// .spawn()?;
///
/// let out = child.output().await?;
/// # std::io::Result::Ok(()) });
/// ```
pub fn output(mut self) -> impl Future<Output = io::Result<Output>> {
// A future that waits for the exit status.
let status = self.status();
// A future that collects stdout.
let stdout = self.stdout.take();
let stdout = async move {
let mut v = Vec::new();
if let Some(mut s) = stdout {
s.read_to_end(&mut v).await?;
}
io::Result::Ok(v)
};
// A future that collects stderr.
let stderr = self.stderr.take();
let stderr = async move {
let mut v = Vec::new();
if let Some(mut s) = stderr {
s.read_to_end(&mut v).await?;
}
io::Result::Ok(v)
};
async move {
let (stdout, stderr) = future::try_zip(stdout, stderr).await?;
let status = status.await?;
Ok(Output {
status,
stdout,
stderr,
})
}
}
}
impl fmt::Debug for Child {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.debug_struct("Child")
.field("stdin", &self.stdin)
.field("stdout", &self.stdout)
.field("stderr", &self.stderr)
.finish()
}
}
/// A handle to a child process's standard input (stdin).
///
/// When a [`ChildStdin`] is dropped, the underlying handle gets clossed. If the child process was
/// previously blocked on input, it becomes unblocked after dropping.
#[derive(Debug)]
pub struct ChildStdin(
#[cfg(windows)] Unblock<std::process::ChildStdin>,
#[cfg(unix)] Async<std::process::ChildStdin>,
);
impl ChildStdin {
/// Convert async_process::ChildStdin into std::process::Stdio.
///
/// You can use it to associate to the next process.
///
/// # Examples
///
/// ```no_run
/// # futures_lite::future::block_on(async {
/// use async_process::Command;
/// use std::process::Stdio;
///
/// let mut ls_child = Command::new("ls").stdin(Stdio::piped()).spawn()?;
/// let stdio:Stdio = ls_child.stdin.take().unwrap().into_stdio().await?;
///
/// let mut echo_child = Command::new("echo").arg("./").stdout(stdio).spawn()?;
///
/// # std::io::Result::Ok(()) });
/// ```
pub async fn into_stdio(self) -> io::Result<std::process::Stdio> {
cfg_if::cfg_if! {
if #[cfg(windows)] {
Ok(self.0.into_inner().await.into())
} else if #[cfg(unix)] {
let child_stdin = self.0.into_inner()?;
blocking_fd(rustix::fd::AsFd::as_fd(&child_stdin))?;
Ok(child_stdin.into())
}
}
}
}
impl io::AsyncWrite for ChildStdin {
fn poll_write(
mut self: Pin<&mut Self>,
cx: &mut Context<'_>,
buf: &[u8],
) -> Poll<io::Result<usize>> {
Pin::new(&mut self.0).poll_write(cx, buf)
}
fn poll_flush(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<io::Result<()>> {
Pin::new(&mut self.0).poll_flush(cx)
}
fn poll_close(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<io::Result<()>> {
Pin::new(&mut self.0).poll_close(cx)
}
}
#[cfg(unix)]
impl AsRawFd for ChildStdin {
fn as_raw_fd(&self) -> RawFd {
self.0.as_raw_fd()
}
}
/// **Note:** This implementation is only available on Rust 1.63+.
#[cfg(all(not(async_process_no_io_safety), unix))]
impl AsFd for ChildStdin {
fn as_fd(&self) -> BorrowedFd<'_> {
self.0.as_fd()
}
}
/// **Note:** This implementation is only available on Rust 1.63+.
#[cfg(all(not(async_process_no_io_safety), unix))]
impl TryFrom<ChildStdin> for OwnedFd {
type Error = io::Error;
fn try_from(value: ChildStdin) -> Result<Self, Self::Error> {
value.0.try_into()
}
}
// TODO(notgull): Add mirroring AsRawHandle impls for all of the child handles
//
// at the moment this is pretty hard to do because of how they're wrapped in
// Unblock, meaning that we can't always access the underlying handle. async-fs
// gets around this by putting the handle in an Arc, but there's still some decision
// to be made about how to handle this (no pun intended)
/// A handle to a child process's standard output (stdout).
///
/// When a [`ChildStdout`] is dropped, the underlying handle gets closed.
#[derive(Debug)]
pub struct ChildStdout(
#[cfg(windows)] Unblock<std::process::ChildStdout>,
#[cfg(unix)] Async<std::process::ChildStdout>,
);
impl ChildStdout {
/// Convert async_process::ChildStdout into std::process::Stdio.
///
/// You can use it to associate to the next process.
///
/// # Examples
///
/// ```no_run
/// # futures_lite::future::block_on(async {
/// use async_process::Command;
/// use std::process::Stdio;
/// use std::io::Read;
/// use futures_lite::AsyncReadExt;
///
/// let mut ls_child = Command::new("ls").stdout(Stdio::piped()).spawn()?;
/// let stdio:Stdio = ls_child.stdout.take().unwrap().into_stdio().await?;
///
/// let mut echo_child = Command::new("echo").stdin(stdio).stdout(Stdio::piped()).spawn()?;
/// let mut buf = vec![];
/// echo_child.stdout.take().unwrap().read(&mut buf).await;
/// # std::io::Result::Ok(()) });
/// ```
pub async fn into_stdio(self) -> io::Result<std::process::Stdio> {
cfg_if::cfg_if! {
if #[cfg(windows)] {
Ok(self.0.into_inner().await.into())
} else if #[cfg(unix)] {
let child_stdout = self.0.into_inner()?;
blocking_fd(rustix::fd::AsFd::as_fd(&child_stdout))?;
Ok(child_stdout.into())
}
}
}
}
impl io::AsyncRead for ChildStdout {
fn poll_read(
mut self: Pin<&mut Self>,
cx: &mut Context<'_>,
buf: &mut [u8],
) -> Poll<io::Result<usize>> {
Pin::new(&mut self.0).poll_read(cx, buf)
}
}
#[cfg(unix)]
impl AsRawFd for ChildStdout {
fn as_raw_fd(&self) -> RawFd {
self.0.as_raw_fd()
}
}
/// **Note:** This implementation is only available on Rust 1.63+.
#[cfg(all(not(async_process_no_io_safety), unix))]
impl AsFd for ChildStdout {
fn as_fd(&self) -> BorrowedFd<'_> {
self.0.as_fd()
}
}
/// **Note:** This implementation is only available on Rust 1.63+.
#[cfg(all(not(async_process_no_io_safety), unix))]
impl TryFrom<ChildStdout> for OwnedFd {
type Error = io::Error;
fn try_from(value: ChildStdout) -> Result<Self, Self::Error> {
value.0.try_into()
}
}
/// A handle to a child process's standard error (stderr).
///
/// When a [`ChildStderr`] is dropped, the underlying handle gets closed.
#[derive(Debug)]
pub struct ChildStderr(
#[cfg(windows)] Unblock<std::process::ChildStderr>,
#[cfg(unix)] Async<std::process::ChildStderr>,
);
impl ChildStderr {
/// Convert async_process::ChildStderr into std::process::Stdio.
///
/// You can use it to associate to the next process.
///
/// # Examples
///
/// ```no_run
/// # futures_lite::future::block_on(async {
/// use async_process::Command;
/// use std::process::Stdio;
///
/// let mut ls_child = Command::new("ls").arg("x").stderr(Stdio::piped()).spawn()?;
/// let stdio:Stdio = ls_child.stderr.take().unwrap().into_stdio().await?;
///
/// let mut echo_child = Command::new("echo").stdin(stdio).spawn()?;
/// # std::io::Result::Ok(()) });
/// ```
pub async fn into_stdio(self) -> io::Result<std::process::Stdio> {
cfg_if::cfg_if! {
if #[cfg(windows)] {
Ok(self.0.into_inner().await.into())
} else if #[cfg(unix)] {
let child_stderr = self.0.into_inner()?;
blocking_fd(rustix::fd::AsFd::as_fd(&child_stderr))?;
Ok(child_stderr.into())
}
}
}
}
impl io::AsyncRead for ChildStderr {
fn poll_read(
mut self: Pin<&mut Self>,
cx: &mut Context<'_>,
buf: &mut [u8],
) -> Poll<io::Result<usize>> {
Pin::new(&mut self.0).poll_read(cx, buf)
}
}
#[cfg(unix)]
impl AsRawFd for ChildStderr {
fn as_raw_fd(&self) -> RawFd {
self.0.as_raw_fd()
}
}
/// **Note:** This implementation is only available on Rust 1.63+.
#[cfg(all(not(async_process_no_io_safety), unix))]
impl AsFd for ChildStderr {
fn as_fd(&self) -> BorrowedFd<'_> {
self.0.as_fd()
}
}
/// **Note:** This implementation is only available on Rust 1.63+.
#[cfg(all(not(async_process_no_io_safety), unix))]
impl TryFrom<ChildStderr> for OwnedFd {
type Error = io::Error;
fn try_from(value: ChildStderr) -> Result<Self, Self::Error> {
value.0.try_into()
}
}
/// A builder for spawning processes.
///
/// # Examples
///
/// ```no_run
/// # futures_lite::future::block_on(async {
/// use async_process::Command;
///
/// let output = if cfg!(target_os = "windows") {
/// Command::new("cmd").args(&["/C", "echo hello"]).output().await?
/// } else {
/// Command::new("sh").arg("-c").arg("echo hello").output().await?
/// };
/// # std::io::Result::Ok(()) });
/// ```
pub struct Command {
inner: std::process::Command,
stdin: bool,
stdout: bool,
stderr: bool,
reap_on_drop: bool,
kill_on_drop: bool,
}
impl Command {
/// Constructs a new [`Command`] for launching `program`.
///
/// The initial configuration (the working directory and environment variables) is inherited
/// from the current process.
///
/// # Examples
///
/// ```
/// use async_process::Command;
///
/// let mut cmd = Command::new("ls");
/// ```
pub fn new<S: AsRef<OsStr>>(program: S) -> Command {
Self::from(std::process::Command::new(program))
}
/// Adds a single argument to pass to the program.
///
/// # Examples
///
/// ```
/// use async_process::Command;
///
/// let mut cmd = Command::new("echo");
/// cmd.arg("hello");
/// cmd.arg("world");
/// ```
pub fn arg<S: AsRef<OsStr>>(&mut self, arg: S) -> &mut Command {
self.inner.arg(arg);
self
}
/// Adds multiple arguments to pass to the program.
///
/// # Examples
///
/// ```
/// use async_process::Command;
///
/// let mut cmd = Command::new("echo");
/// cmd.args(&["hello", "world"]);
/// ```
pub fn args<I, S>(&mut self, args: I) -> &mut Command
where
I: IntoIterator<Item = S>,
S: AsRef<OsStr>,
{
self.inner.args(args);
self
}
/// Configures an environment variable for the new process.
///
/// Note that environment variable names are case-insensitive (but case-preserving) on Windows,
/// and case-sensitive on all other platforms.
///
/// # Examples
///
/// ```
/// use async_process::Command;
///
/// let mut cmd = Command::new("ls");
/// cmd.env("PATH", "/bin");
/// ```
pub fn env<K, V>(&mut self, key: K, val: V) -> &mut Command
where
K: AsRef<OsStr>,
V: AsRef<OsStr>,
{
self.inner.env(key, val);
self
}
/// Configures multiple environment variables for the new process.
///
/// Note that environment variable names are case-insensitive (but case-preserving) on Windows,
/// and case-sensitive on all other platforms.
///
/// # Examples
///
/// ```
/// use async_process::Command;
///
/// let mut cmd = Command::new("ls");
/// cmd.envs(vec![("PATH", "/bin"), ("TERM", "xterm-256color")]);
/// ```
pub fn envs<I, K, V>(&mut self, vars: I) -> &mut Command
where
I: IntoIterator<Item = (K, V)>,
K: AsRef<OsStr>,
V: AsRef<OsStr>,
{
self.inner.envs(vars);
self
}
/// Removes an environment variable mapping.
///
/// # Examples
///
/// ```
/// use async_process::Command;
///
/// let mut cmd = Command::new("ls");
/// cmd.env_remove("PATH");
/// ```
pub fn env_remove<K: AsRef<OsStr>>(&mut self, key: K) -> &mut Command {
self.inner.env_remove(key);
self
}
/// Removes all environment variable mappings.
///
/// # Examples
///
/// ```
/// use async_process::Command;
///
/// let mut cmd = Command::new("ls");
/// cmd.env_clear();
/// ```
pub fn env_clear(&mut self) -> &mut Command {
self.inner.env_clear();
self
}
/// Configures the working directory for the new process.
///
/// # Examples
///
/// ```
/// use async_process::Command;
///
/// let mut cmd = Command::new("ls");
/// cmd.current_dir("/");
/// ```
pub fn current_dir<P: AsRef<Path>>(&mut self, dir: P) -> &mut Command {
self.inner.current_dir(dir);
self
}
/// Configures the standard input (stdin) for the new process.
///
/// # Examples
///
/// ```
/// use async_process::{Command, Stdio};
///
/// let mut cmd = Command::new("cat");
/// cmd.stdin(Stdio::null());
/// ```
pub fn stdin<T: Into<Stdio>>(&mut self, cfg: T) -> &mut Command {
self.stdin = true;
self.inner.stdin(cfg);
self
}
/// Configures the standard output (stdout) for the new process.
///
/// # Examples
///
/// ```
/// use async_process::{Command, Stdio};
///
/// let mut cmd = Command::new("ls");
/// cmd.stdout(Stdio::piped());
/// ```
pub fn stdout<T: Into<Stdio>>(&mut self, cfg: T) -> &mut Command {
self.stdout = true;
self.inner.stdout(cfg);
self
}
/// Configures the standard error (stderr) for the new process.
///
/// # Examples
///
/// ```
/// use async_process::{Command, Stdio};
///
/// let mut cmd = Command::new("ls");
/// cmd.stderr(Stdio::piped());
/// ```
pub fn stderr<T: Into<Stdio>>(&mut self, cfg: T) -> &mut Command {
self.stderr = true;
self.inner.stderr(cfg);
self
}
/// Configures whether to reap the zombie process when [`Child`] is dropped.
///
/// When the process finishes, it becomes a "zombie" and some resources associated with it
/// remain until [`Child::try_status()`], [`Child::status()`], or [`Child::output()`] collects
/// its exit code.
///
/// If its exit code is never collected, the resources may leak forever. This crate has a
/// background thread named "async-process" that collects such "zombie" processes and then
/// "reaps" them, thus preventing the resource leaks.
///
/// The default value of this option is `true`.
///
/// # Examples
///
/// ```
/// use async_process::{Command, Stdio};
///
/// let mut cmd = Command::new("cat");
/// cmd.reap_on_drop(false);
/// ```
pub fn reap_on_drop(&mut self, reap_on_drop: bool) -> &mut Command {
self.reap_on_drop = reap_on_drop;
self
}
/// Configures whether to kill the process when [`Child`] is dropped.
///
/// The default value of this option is `false`.
///
/// # Examples
///
/// ```
/// use async_process::{Command, Stdio};
///
/// let mut cmd = Command::new("cat");
/// cmd.kill_on_drop(true);
/// ```
pub fn kill_on_drop(&mut self, kill_on_drop: bool) -> &mut Command {
self.kill_on_drop = kill_on_drop;
self
}
/// Executes the command and returns the [`Child`] handle to it.
///
/// If not configured, stdin, stdout and stderr will be set to [`Stdio::inherit()`].
///
/// # Examples
///
/// ```no_run
/// # futures_lite::future::block_on(async {
/// use async_process::Command;
///
/// let child = Command::new("ls").spawn()?;
/// # std::io::Result::Ok(()) });
/// ```
pub fn spawn(&mut self) -> io::Result<Child> {
if !self.stdin {
self.inner.stdin(Stdio::inherit());
}
if !self.stdout {
self.inner.stdout(Stdio::inherit());
}
if !self.stderr {
self.inner.stderr(Stdio::inherit());
}
Child::new(self)
}
/// Executes the command, waits for it to exit, and returns the exit status.
///
/// If not configured, stdin, stdout and stderr will be set to [`Stdio::inherit()`].
///
/// # Examples
///
/// ```no_run
/// # futures_lite::future::block_on(async {
/// use async_process::Command;
///
/// let status = Command::new("cp")
/// .arg("a.txt")
/// .arg("b.txt")
/// .status()
/// .await?;
/// # std::io::Result::Ok(()) });
/// ```
pub fn status(&mut self) -> impl Future<Output = io::Result<ExitStatus>> {
let child = self.spawn();
async { child?.status().await }
}
/// Executes the command and collects its output.
///
/// If not configured, stdin will be set to [`Stdio::null()`], and stdout and stderr will be
/// set to [`Stdio::piped()`].
///
/// # Examples
///
/// ```no_run
/// # futures_lite::future::block_on(async {
/// use async_process::Command;
///
/// let output = Command::new("cat")
/// .arg("a.txt")
/// .output()
/// .await?;
/// # std::io::Result::Ok(()) });
/// ```
pub fn output(&mut self) -> impl Future<Output = io::Result<Output>> {
if !self.stdin {
self.inner.stdin(Stdio::null());
}
if !self.stdout {
self.inner.stdout(Stdio::piped());
}
if !self.stderr {
self.inner.stderr(Stdio::piped());
}
let child = Child::new(self);
async { child?.output().await }
}
}
impl From<std::process::Command> for Command {
fn from(inner: std::process::Command) -> Self {
Self {
inner,
stdin: false,
stdout: false,
stderr: false,
reap_on_drop: true,
kill_on_drop: false,
}
}
}
impl fmt::Debug for Command {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
if f.alternate() {
f.debug_struct("Command")
.field("inner", &self.inner)
.field("stdin", &self.stdin)
.field("stdout", &self.stdout)
.field("stderr", &self.stderr)
.field("reap_on_drop", &self.reap_on_drop)
.field("kill_on_drop", &self.kill_on_drop)
.finish()
} else {
// Stdlib outputs command-line in Debug for Command. This does the
// same, if not in "alternate" (long pretty-printed) mode.
// This is useful for logs, for example.
fmt::Debug::fmt(&self.inner, f)
}
}
}
/// Moves `Fd` out of non-blocking mode.
#[cfg(unix)]
fn blocking_fd(fd: rustix::fd::BorrowedFd<'_>) -> io::Result<()> {
cfg_if::cfg_if! {
// ioctl(FIONBIO) sets the flag atomically, but we use this only on Linux
// for now, as with the standard library, because it seems to behave
// differently depending on the platform.
// https://github.com/rust-lang/rust/commit/efeb42be2837842d1beb47b51bb693c7474aba3d
// https://github.com/libuv/libuv/blob/e9d91fccfc3e5ff772d5da90e1c4a24061198ca0/src/unix/poll.c#L78-L80
// https://github.com/tokio-rs/mio/commit/0db49f6d5caf54b12176821363d154384357e70a
if #[cfg(target_os = "linux")] {
rustix::io::ioctl_fionbio(fd, false)?;
} else {
let previous = rustix::fs::fcntl_getfl(fd)?;
let new = previous & !rustix::fs::OFlags::NONBLOCK;
if new != previous {
rustix::fs::fcntl_setfl(fd, new)?;
}
}
}
Ok(())
}
#[cfg(unix)]
mod test {
#[test]
fn test_into_inner() {
futures_lite::future::block_on(async {
use crate::Command;
use std::io::Result;
use std::process::Stdio;
use std::str::from_utf8;
use futures_lite::AsyncReadExt;
let mut ls_child = Command::new("cat")
.arg("Cargo.toml")
.stdout(Stdio::piped())
.spawn()?;
let stdio: Stdio = ls_child.stdout.take().unwrap().into_stdio().await?;
let mut echo_child = Command::new("grep")
.arg("async")
.stdin(stdio)
.stdout(Stdio::piped())
.spawn()?;
let mut buf = vec![];
let mut stdout = echo_child.stdout.take().unwrap();
stdout.read_to_end(&mut buf).await?;
dbg!(from_utf8(&buf).unwrap_or(""));
Result::Ok(())
})
.unwrap();
}
}
Reference in New Issue View Git Blame Copy Permalink