This updates the tokio `Command` and `Child` behavior to match that of
the stdlib: spawned processes will *not* be automatically killed when
the handle is dropped
Unlike the stdlib, any dropped (unix) processes may be reaped by tokio
behind-the-scenes after they exit and if new processes are awaited,
which mitigates the risks of piling up unreaped zombie unix processes
A `Command::kill_on_drop` method is added to allow the caller to
control whether the spawned child should be killed when the handle is
dropped. By default, this value is `false`.
The `Child::forget` method has been removed, as it is superseded by
`Command::kill_on_drop`
This avoids having consumers import libc for common signals, and it
improves discoverability since users need not be aware that libc
contains all supported constants.
Windows guarantees handler routines are always invoked in a new thread
(https://docs.microsoft.com/en-us/windows/console/handlerroutine), so we
don't need to use the handler-wake-another-driver technique used in the
Unix implementation
By broadcasting the event notifications from the handler, we no longer
need the Driver task to be spawned, which fixes the starvation issue if
the executor which runs the Driver task goes away
Also changed the behavior so that the default event handler runs if
all listeners for CTRL_{C, BREAK} events go away.
* Denied all warnings in tests, and denied rust_2018_idioms violations
* Bumped the crate version and set publish = false
* Pruned dependencies:
- Only pull in tokio-sync on windows where it is used
- Removed unused dev-dependencies
* Switch to Async{Read, Write} traits from tokio-io rather than
futures-io
* Use #[tokio::test] where possible
* Removed deprecated items
* Fix all doc examples
* This simplifies the API surface by returning () instead of the signal
number that was used during registration. This also more closely mirrors
the cross-platform `CtrlC` event stream API
* This is a **breaking change**
* Add a new `windows::CtrlBreak` struct which wil represent a stream of
CTRL_BREAK_EVENT signals on Windows systems
* The `windows::Event` type is no longer publicly accessible and is
replaced by using `CtrlC` or `windows::CtrlBreak`.
[breaking-change]
* Add a new `CtrlC` struct which will represent a stream of SIGINT
signals on Unix or the CTRL_C event on Windows
* `CtrlC` implements `Stream<Output = ()>` rather than `IoSteam` as
previously
Migrate to std::futures and the futures 0.3 preview and use async/await
where possible
**Breaking change:** the IoFuture and IoStream definitions used to refer
to Box<dyn Future> and Box<dyn Stream>, but now they are defined as
Pin<...> versions which are technically breaking.
No other breaking or functional changes have been made
Today the Unix and Windows implementations have similar yet differing
implementations of hooking into OS events and propagating them to any
listening futures. Rather than re-implement the same behavior two
different ways, we should factor out any commonality into a shared
module and keep the Unix/Windows modules focused solely on OS
integrations.
Reusing the same implementation across OS versions also allows for more
consistent behavior between platforms, which also makes squashing bugs
much easier.
This change introduces the `registry` module which handles creating and
initializing a global map of signals/events and their registered
listeners. Each OS specific module is expected to implement the OS hooks
which delegate to invoking the registry module's methods for
distributing the event notifications.
# Use registry module for Windows implementation
Note this still uses the same architecture as previously: a driver task
is spawned by the first registered event, and that task is responsible
for delivering any events to registered futures. (If that first event
loop goes away, all events will deadlock). A solution to this issue will
be explored at a later time.
- Use `Handle::default` over `Handle::current` for consistent semantics
- Make all `windows::Event` constructors lazily invoke `global_init`
so they can be safely constructed off-task
- Don't assume the reactor is alive and event registration will be done
when calling `global_init`
Add windows regression tests. Unfortunately, Windows doesn't have a
reliable way of programmatically sending CTRL_C or CTRL_BREAK events
to a progress, so the tests can only exercise our internal machinery by
invoking the handler that we register with the OS
Fixes#999
* Minimize allocation needed for channels
* Use a newtype for signal ids
* We can just cast the raw pointer to a `usize` and still perform a
simple identity check, without incurring any implications of storing a
raw pointer (e.g. previously Signal was !Sync and had an unsafe impl of
Send, and now it is naturally Sync+Send)
* Broadcast with `try_send` instead of `start_send`
The `Stream::start_send` method uses backpressure and schedules the
current task to be notified whenever the channel has additional room,
which means we'll generate a lot of unnecessary wakeups whenever a
channel gets full
By changing to `try_send` and handling any errors, we ensure the
Driver's task won't get woken up when a Signal finally consumes its
notification, since we're coalescing things anyway
Since the CI runs all tests for all tokio crates, it is possible that a
sporadic failure in one crate can mask failures/successes of other
crates' tests.
Using the `--no-fail-fast` flag instructs cargo to run *all* tests
before failing the build. This will allow checking to see if any
relevant test cases still pass even if an unrelated test has failed.
* Originally reported in alexcrichton/tokio-process#42
* The root cause appears to be due to two different PollEvented
instances trying to consume readiness events from the same file
descriptor.
* Previously we would simply swallow any `AlreadyExists` errors when
attempting to register the pipe receiver with the event loop. I'm not
sure if this means the PollEvented wrapper wasn't fully registered to
receive events, or maybe there is a potential race condition with how
PollEvented consumes mio readiness events. Using a fresh/duplicate file
descriptor appears to mitigate the issue, however.
* I was also not able to reproduce the issue as an isolated test case so
there is no regression test available within this crate (but we can add
one in tokio-process)
Ivan Petkov