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
## Motivation
The `tokio-trace` and `tokio-trace-core` crates have been renamed to
`tracing` and `tracing-core`, and moved to their own repository
(`tokio-rs/tracing`).
## Solution
This branch removes `tokio-trace` and `tokio-trace-core` from the
`tokio` repository. In addition, I've added a "Related Projects" section
to the root README, which lists `tracing` (as well as `mio`, and
`bytes`) as other libraries maintained by the Tokio project. I thought
that this would help folks looking for `tokio-trace` here find it in its
new home.
In addition, it changes `tokio` to depend on `tracing-core` rather than
`tokio-trace-core`.
Closes#1159
Signed-off-by: Eliza Weisman <[email protected]>
An initial pass at updating `tokio-threadpool` to `std::future`. The
codebase and tests both now run using `std::future` but the wake
mechanism is not ideal. Follow up work will be required to improve on
this.
Refs: #1200
Strategy was to
- copy the old codec code that was temporarily being stashed in `tokio-io`
- modify all the type signatures to use Pin, as literal a translation as possible
- fix up the tests likewise
This is intended just to get things compiling and passing tests. Beyond that there is surely
lots of refactoring that can be done to make things more idiomatic. The docs are unchanged.
Closes#1189
A first pass at updating Tokio to use `std::future`.
Implementations of `Future` from the futures crate are updated to implement
`Future` from std. Implementations of `Stream` are moved to a feature flag.
This commits disables a number of crates that have not yet been updated.
Adds a `TypedExecutor` trait that describes how to spawn futures of a specific
type. This is useful for implementing functions that are generic over an executor
and wish to support both `Send` and `!Send` cases.
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## Motivation
In asynchronous systems like Tokio, interpreting traditional log
messages can often be quite challenging. Since individual tasks are
multiplexed on the same thread, associated events and log lines are
intermixed making it difficult to trace the logic flow. Currently, none
of the available logging frameworks or libraries in Rust offer the
ability to trace logical paths through a futures-based program.
There also are complementary goals that can be accomplished with such a
system. For example, metrics / instrumentation can be tracked by
observing emitted events, or trace data can be exported to a distributed
tracing or event processing system.
In addition, it can often be useful to generate this diagnostic data in
a structured manner that can be consumed programmatically. While prior
art for structured logging in Rust exists, it is not currently
standardized, and is not "Tokio-friendly".
## Solution
This branch adds a new library to the tokio project, `tokio-trace`.
`tokio-trace` expands upon logging-style diagnostics by allowing
libraries and applications to record structured events with additional
information about *temporality* and *causality* --- unlike a log
message, a span in `tokio-trace` has a beginning and end time, may be
entered and exited by the flow of execution, and may exist within a
nested tree of similar spans. In addition, `tokio-trace` spans are
*structured*, with the ability to record typed data as well as textual
messages.
The `tokio-trace-core` crate contains the core primitives for this
system, which are expected to remain stable, while `tokio-trace` crate
provides a more "batteries-included" API. In particular, it provides
macros which are a superset of the `log` crate's `error!`, `warn!`,
`info!`, `debug!`, and `trace!` macros, allowing users to begin the
process of adopting `tokio-trace` by performing a drop-in replacement.
## Notes
Work on this project had previously been carried out in the
[tokio-trace-prototype] repository. In addition to the `tokio-trace` and
`tokio-trace-core` crates, the `tokio-trace-prototype` repo also
contains prototypes or sketches of adapter, compatibility, and utility
crates which provide useful functionality for `tokio-trace`, but these
crates are not yet ready for a release. When this branch is merged, that
repository will be archived, and the remaining unstable crates will be
moved to a new `tokio-trace-nursery` repository. Remaining issues on the
`tokio-trace-prototype` repo will be moved to the appropriate new repo.
The crates added in this branch are not _identical_ to the current head
of the `tokio-trace-prototype` repo, as I did some final clean-up and docs
polish in this branch prior to merging this PR.
[tokio-trace-prototype]: https://github.com/hawkw/tokio-trace-prototypeCloses: #561
Signed-off-by: Eliza Weisman <[email protected]>
Introduce a tokio-sync crate containing useful synchronization primitives for programs
written using Tokio.
The initial release contains:
* An mpsc channel
* A oneshot channel
* A semaphore implementation
* An `AtomicTask` primitive.
The `oneshot` and `mpsc` channels are new implementations providing improved
performance characteristics. In some benchmarks, the new mpsc channel shows
up to 7x improvement over the version provided by the `futures` crate. Unfortunately,
the `oneshot` implementation only provides a slight performance improvement as it
is mostly limited by the `futures` 0.1 task system. Once updated to the `std` version
of `Future` (currently nightly only), much greater performance improvements should
be achievable by `oneshot`.
Additionally, he implementations provided here are checked using
[Loom](http://github.com/carllerche/loom/), which provides greater confidence of
correctness.
Disabling all features means the only dependency is `futures`.
Relevant pieces of the API can then be enabled with the following features:
- `codec`
- `fs`
- `io`
- `reactor`
- `tcp`
- `timer`
- `udp`
- `uds`
This also introduces the beginnings of enabling only certain pieces of the `Runtime`. As a start, the entire default runtime API is enabled via the `rt-full` feature.
This patch adds experimental async/await support to Tokio. It does this
by adding feature flags to existing libs only where necessary in order
to add nightly specific code (mostly `Unpin` implementations). It then
provides a new crate: `tokio-async-await` which is a shim layer on top
of `tokio`.
The `tokio-async-await` crate is expected to look exactly like `tokio`
does, but with async / await support. This strategy reduces the amount
of cfg guarding in the main libraries.
This patch also adds `tokio-channel`, which is copied from futures-rs
0.1 and adds the necessary `Unpin` implementations. In general, futures
0.1 is mostly unmaintained, so it will make sense for Tokio to take over
maintainership of key components regardless of async / await support.
This also bumps a number of sub crates:
* tokio-executor (0.1.3)
* tokio-io (0.1.8)
* tokio-reactor (0.1.4)
* tokio-threadpool (0.1.6)
* tokio-timer (0.2.6)
* tokio-udp (0.1.2)
