33 stable releases
1.3.0 | Sep 16, 2024 |
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1.1.26 | Mar 3, 2024 |
1.1.24 | Nov 17, 2023 |
1.1.3 | Jul 16, 2023 |
0.1.3 | Jun 7, 2023 |
#90 in Asynchronous
86 downloads per month
Used in reactive-messaging
4.5MB
11K
SLoC
reactive-mutiny crate
async & zero-cost-abstraction Event-Driven Reactive Library for Rust with advanced & optimized containers and Stream executors
Browse the Docs.
Rust's reactive-mutiny
was designed to allow building efficient & elegant asynchronous event processing pipelines (using
Streams -- a.k.a. "async Iterators"), easing flexible & decoupled microservice architectures (distributed or not), ready for production.
The core of this library is composed of a Uni
and a Multi
-- hence the name "Mutiny". Both process streams of events:
Uni
allows a single listener OR multiple consumers for each produced payload -- also definable as allows a single event processing pipeline;Multi
allows multiple listeners AND multiple consumers for each produced payload, allowing several event processing pipelines -- or, in Kafka parlance, allowing several consumer groupsMulti
may do whatUni
does, but the later does it faster -- hence, justifying its existence:Uni
doesn't use any reference counting for the payloads and uses a single queue/channel (whereMulti
requires as many as there are listeners).
Moreover, zero-cost-abstractions over metrics, logs & retrying are available -- getting optimized away if not used, as specified in const time initialization options and on functional, deeper API opt-ins.
Taste the library in this excerpt:
use reactive_mutiny::prelude::*;
fn logic_1(events_stream: impl Stream<Item=InputEventType>) -> impl Stream<Item=OutputEventType> {
// your logic goes here using Rust's Stream / Iterator functions
}
fn main() {
// build the event processing pipeline
let events_handle = UniZeroCopy::<InputEventType, 1024, 1>::new()
.spawn_non_futures_non_fallible_executor("Consumer of InputEventType and issiuer of OutputEventType",
|events_stream| {
logic_2(logic_1(events_stream))
.inspect(|outgoing_event| send(outgoing_event))
},
|_executor| async { /* on-close logic */ });
}
// see more details in examples/uni-microservice
Core components:
- A set of channels through which events are sent from producers to consumers -- all context-switch-free (AKA "lock-free") -- including zero-copy & mmap log based implementations;
- A set of generic
Stream
executors for all possible combinations of Future/non-Future & Fallible/non-Fallible event types, with the option of enforcing or not a Timeout on each event's resolution of theirFuture
. The API was carefully designed to allow the compiler to fully optimize everything: most of times, all of the reactive code ends up in the executors and the whole Multi / Uni abstractions are zeroed out; - Instrumentation & Metrics collectors for visibility of the performance and operation (as said earlier, as a zero-cost-abstraction);
- The main
Multi
andUni
objects, along with a set of prelude type aliases binding the channels and allocators together. - Constant-pool based allocators, for superior performance and flexibility -- see the
AtomicZeroCopy
channel benchmarks;
NOTE: This crate is rather new (less than 1yo), but actively maintained and used in production: no known bugs exist (and MIRI says we're fine), speed is amazing, API has been throughoutly tested & reviewed and is stable, but improved docs & code cleanup / refactorings will still be (slowly) addressed to improve the cosmetics. Anyway, evolutions are always driven from community feedback
MIRI: Not all parts of this crate are testable with MIRI, as of 2023-06-14: "ready events from epoll_wait is not yet implemented"; "mmap syscalls" and some other functionalities are not available in MIRI -- but what is able to be tested, passes.
Performance
This crate was very loosely inspired by the SmallRye's Mutiny library for Java, from which some names were borrowed.
Little had to be done to bring the same functionality to Rust, due to the native functional approach, powerful error
handling, async support and wonderful & flexible Iterator/Stream APIs supported by the language, so the focus of this work went into
bringing the events to their maximum processing speed & operability: special queues, topics, stacks, channels and Stream executors have
been created, offering a superior performance over the Rust's native & community versions -- inspect the benches
folder for details:
performance characteristics of the standard/community vs our provided raw senders of payloads from one thread to another
performance characteristics comparison of standard vs our provided type wrappers and allocators, used for zero-copy channels -- with raw memcopy
and allocators baselines
Where to go next
Docs will still be improved. Meanwhile, the following sequence is suggested for new users of this crate:
- Look at the
examples/
; - Study the type aliases in
reactive-mutiny::prelude::advanced::*
-- at this point, it is safe to trust that the docs will provide everything you'll need; - For an advanced usage example, inspect the
reactive-messaging
crate -- in special, how easily & decoupled the reactive abstractions allow upgrading a processor that doesn't pass any answers back to one that does pass them back to the peers.
Comparisons
If you're familiar with SmallRye's Mutiny, here are some key differences:
- Both our
Uni
andMulti
here process streams of events. On the original library, a Uni is like a single "async future" and, since we don't need that in Rust, the names were repurposed: the other Multi is ourUni
(may also work as ourMulti
when using "subscriptions") and the other Uni you may get by just using any Rust's async calls & handling anyResult<>
, for error treatment; - Each event fed into the pipeline will be executed, regardless if there is an answer at the end; also, there is no "subscription"
(subscription semantics is achieved by adding pipelines to a
Multi
); - Executors & their settings are set when the pair producer/pipeline comes to be (when the
Uni
/Multi
object is created): there is no .merge() nor .executeAt() to call in the pipeline; - No Multi/Uni pipeline conversion and the corresponding plethora of functions -- they are simply not needed;
- No timeouts are set in the pipeline -- they are a matter for the executor, which will simply cancel events (that are
Future
s) that take longer than the configured executor's maximum (SmallRye's Uni timeouts are attainable using Tokio's "futures" timeouts, just like one would do for any async function call); - Incredibly faster: Rust's compiler makes your pipelines (and most of this library) behave as a zero-cost abstraction (when compiled in Release mode). The used-and-abused Const Generics play a great role in such optimizations -- at the expense of our rather complex type definitions in
reactive_mutiny::prelude::advanced
. - To fully get the original Mutiny's behavior, you'll have to use:
- Rust's
reactive-mutiny
(for reactive async event-processing); Tokio
(to get responses from Futures and to specify timeouts in async calls, async sleeps... saving a ton of APIs for this crate);- Streams (here we don't mix Multi & Stream & Iterator functionalities -- which, in practice, leads to inefficient abuses of the original Java library's abstractions -- for using a new instance of their Multi where a Stream or Iterator could be used is a common bad parctice / anti-pattern);
- Rust's
Dependencies
~15–22MB
~123K SLoC