feat(swarm): Add AndBehaviour #3366

jxs · 2023-01-21T19:03:03Z

Description

Addresses #2719.

Notes

I started this by basically following the code generated by a NetworkBehaviour derive implementation for a struct similar to And (but without generic fields) but then it seemed a lot of similar code to the generated macro to maintain.

I then followed to the approach submitted on this PR, have the And struct itself the NetworkBehaviour derived. While going for this approach I found a bug with the NetworkBehaviour derive implementation for generics, when out_event was not provided the enum generated missed the NetworkBehaviour impl constraint for the generic variants whilst using the generics for <Generic>::OutEvent. This is what a4570af addresses.

The manual Debug implementation was required because the Debug derive is not smart enough, when we annotate it on a struct with generics it requires it's generics to impl Debug but on our case what we want is that only the OutEvent associated type of the generic variants implement Debug. see similar here or here

The derive macro shouldn't be breaking, from what I tested the printed debug output is the same for non generic types.
I updated the ping example to use And, if agreed will update the other examples.
If this seems to hacky I can rollback and submit instead the first approach.

Links to any relevant issues

Open Questions

Change checklist

I have performed a self-review of my own code
I have made corresponding changes to the documentation
I have added tests that prove my fix is effective or that my feature works
A changelog entry has been made in the appropriate crates

thomaseizinger · 2023-01-21T22:20:18Z

Hmm, I think the fix is worth landing (maybe even in a separate PR?).

If And is this trivial to implement, I don't think we need to provide it? Not sure. It might be a nice utility to have. Perhaps we should be implementing NetworkBehaviour for tuples?

for generic types when out_event was not provided. Previously The enum generated didn't have the NetworkBehaviour impl constraints whilst using the generics for <Generic>::OutEvent.

instead of a custom structure that derives `NetworkBehaviour`.

jxs · 2023-01-23T11:59:08Z

Good question!
IIUC you are suggesting tupples so we can have more than two elements right?
AFACT to implement NetworkBehaviour for tuples it seems we would need to do it manually, (see here or here how std does it for its traits) instead of deriving.

So it seems a matter of choosing where to have more complexity, either in the code (manually implementation) or in the user API, <And<A, And<B, C>> which would mean and.second_as_ref().first_as_ref() to access it's behaviours, and AndEvent(AndEvent(Behaviour) vs tuple.2 and TupleEvent(Behaviour).
No strong opinion on my end Thomas.

mergify · 2023-01-23T16:34:32Z

This pull request has merge conflicts. Could you please resolve them @jxs? 🙏

…iour

thomaseizinger · 2023-01-23T23:45:17Z

My vote would go against providing an And type. The implementation is so trivial, users can just create it themselves when they need it, esp. if they need to compose more than two behaviours.

mergify · 2023-01-24T01:13:57Z

This pull request has merge conflicts. Could you please resolve them @jxs? 🙏

mxinden

I am still in favor of adding an And NetworkBehaviour, even though it is very simple. Not a strong opinion.

Can you please extract the swarm-derive fix into a separate pull request @jxs?

mxinden · 2023-01-26T12:17:19Z

swarm-derive/CHANGELOG.md

@@ -1,9 +1,14 @@
 # 0.32.0 [unreleased]

+- Fix `NetworkBehaviour` Derive macro for generic types when `out_event` was not provided. Previously The enum generated


Suggested change

- Fix `NetworkBehaviour` Derive macro for generic types when `out_event` was not provided. Previously The enum generated

- Fix `NetworkBehaviour` Derive macro for generic types when `out_event` was not provided. Previously the enum generated

Thanks Max, addressed in #3393

mxinden · 2023-01-26T12:17:56Z

swarm/CHANGELOG.md

@@ -1,5 +1,10 @@
 # 0.42.0 [unreleased]

+- Add `And` struct that combines two `NetworkBehaviour` implementations. Helfpful for when one wants


Suggested change

- Add `And` struct that combines two `NetworkBehaviour` implementations. Helfpful for when one wants

- Add `And` struct that combines two `NetworkBehaviour` implementations. Helpful for when one wants

thanks! updated!

mxinden · 2023-01-26T12:21:00Z

swarm/src/behaviour.rs

+/// Implementation of [`NetworkBehaviour`] that combines two underlying implementations.
+#[cfg(feature = "macros")]
+#[derive(Debug, Default, libp2p_swarm_derive::NetworkBehaviour)]
+#[behaviour(prelude = "crate::derive_prelude")]
+pub struct And<A, B> {
+    first: A,
+    second: B,
+}


NetworkBehaviour combinators like Toggle and Either are in their own file. I would suggest doing the same for And.

Thanks, Addressed!

thomaseizinger · 2023-01-26T21:38:24Z

I am still in favor of adding an And NetworkBehaviour, even though it is very simple. Not a strong opinion.

Can you please extract the swarm-derive fix into a separate pull request @jxs?

If we add it, I think the fields should just be public to make access easier.

elenaf9 · 2023-01-27T10:16:24Z

swarm/src/behaviour.rs

@@ -40,6 +41,47 @@ pub(crate) type THandlerInEvent<THandler> =
 pub(crate) type THandlerOutEvent<THandler> =
    <<THandler as IntoConnectionHandler>::Handler as ConnectionHandler>::OutEvent;

+/// Implementation of [`NetworkBehaviour`] that combines two underlying implementations.
+#[cfg(feature = "macros")]
+#[derive(Debug, Default, libp2p_swarm_derive::NetworkBehaviour)]


Right now this will have the macro-generated OutEvent looking kinda like this:

enum AndEvent<A, B> { First(A) Second(B) }

What do you think about specifying Either<A, B> as out-event instead? Would also be more consistent with all of our other "combinators".

Good point. Note @jxs that you can still achieve the above suggestion with the derive macro by using the out_event derive parameter, see https://docs.rs/libp2p-swarm/latest/libp2p_swarm/behaviour/trait.NetworkBehaviour.html#custom-networkbehaviour-with-the-derive-macro.

Yeah I tried that while experimenting, but when you specify a custom out_event one has to impl From for each subvariant. In case of using Either the generated code is the following:

impl<A, B> crate::derive_prelude::NetworkBehaviour for And<A, B> where A: crate::derive_prelude::NetworkBehaviour, B: crate::derive_prelude::NetworkBehaviour, Either<A, B>: From<<A as crate::derive_prelude::NetworkBehaviour>::OutEvent>, Either<A, B>: From<<B as crate::derive_prelude::NetworkBehaviour>::OutEvent>,

which kinda doesn't make sense as it would require for us to know A and B, and means that specifying out_event for a derived NetworkBehaviour with generics is not supported now. Thanks for referring that Elena. I am kind of out of ideas to allow derive to support custom out_event for generic structures. Do you ave any suggestion? Else I can add this to the doc.

Ahh yes you're right. Using Either as out-event would only be possible if we manually derive NetworkBehaviour. I don't feel strongly about it, thus I'm fine with sticking with the current solution.

I am kind of out of ideas to allow derive to support custom out_event for generic structures. Do you ave any suggestion?

I don't think its possible. We will always run into the issue of conflicting implementations if we try to auto-implement From, since A and B theoretically may have the same type.

I think this is a point for not providing an And behaviour. If a user wants to group a set of NetworkBehaviours together, they can do so themselves and provide a more meaningful name than And. Like, if they combine certain behaviours together than are only available to under a "legacy" feature-toggle, they can call this behaviour Legacy and the generated name will make more sense.

Plus, they can add as many behaviours as they want, not just two, they can decide on the visibility, they can decide on the names etc.

I really don't see the value in providing an And behaviour.

jxs · 2023-01-27T13:01:06Z

Opened #3393

I am still in favor of adding an And NetworkBehaviour, even though it is very simple. Not a strong opinion.
Can you please extract the swarm-derive fix into a separate pull request @jxs?

If we add it, I think the fields should just be public to make access easier.

``

I am still in favor of adding an And NetworkBehaviour, even though it is very simple. Not a strong opinion.
Can you please extract the swarm-derive fix into a separate pull request @jxs?

If we add it, I think the fields should just be public to make access easier.

Yeah, it's the dilemma regarding being allowed to make changes without breaking API easily vs easier to access API, funny enough I thought you'd go for the first 😁 Updated!

…iour

jxs · 2023-01-27T13:08:49Z

meanwhile opened #3393 but forgot to open it from a libp2p/rust-libp2p repo so we could then make this one target it sorry. After that one gets merged this one will be updated.

use ReadyUpgrade for Handler::InboundProtocol

use ReadyUpgrade for Handler::OutboundProtocol.

mergify · 2023-02-01T21:33:44Z

This pull request has merge conflicts. Could you please resolve them @jxs? 🙏

…iour

This reverts commit 2c9ac06.

This reverts commit a0464a3.

thomaseizinger

I am against adding this. See discussion: #3366 (comment).

mergify · 2023-02-14T01:12:51Z

This pull request has merge conflicts. Could you please resolve them @jxs? 🙏

jxs marked this pull request as draft January 21, 2023 19:04

jxs force-pushed the and-behaviour branch from a3c4a0c to 6b729f9 Compare January 21, 2023 19:10

jxs force-pushed the and-behaviour branch 2 times, most recently from 32d2f44 to e8d6e00 Compare January 22, 2023 00:22

jxs changed the title ~~feat(swarm)!: Add AndBehaviour~~ feat(swarm): Add AndBehaviour Jan 22, 2023

jxs force-pushed the and-behaviour branch 2 times, most recently from fff9e31 to 910f7c7 Compare January 23, 2023 10:46

jxs added 3 commits January 23, 2023 10:50

swarm_derive: Fix NetworkBehaviour Derive macro

9e3298b

for generic types when out_event was not provided. Previously The enum generated didn't have the NetworkBehaviour impl constraints whilst using the generics for <Generic>::OutEvent.

swarm: implement And NetworkBehaviour.

5edefcd

examples: update ping example to use And

ff3c982

instead of a custom structure that derives `NetworkBehaviour`.

jxs force-pushed the and-behaviour branch from 910f7c7 to ff3c982 Compare January 23, 2023 10:50

jxs marked this pull request as ready for review January 23, 2023 11:58

jxs requested review from mxinden and thomaseizinger January 23, 2023 12:00

Merge branch 'master' of github.com:libp2p/rust-libp2p into and-behav…

7b1cb7e

…iour

mxinden reviewed Jan 26, 2023

View reviewed changes

jxs mentioned this pull request Jan 26, 2023

fix(swarm-derive): add bounds to OutEvent on generic fields #3393

Merged

4 tasks

elenaf9 reviewed Jan 27, 2023

View reviewed changes

jxs added 3 commits January 27, 2023 12:00

swarm: move and to its own module.

5a9a84d

fix typo in CHANGELOG.md

842e30d

expose And fields and remove getters and setters.

69e452c

Merge branch 'master' of github.com:libp2p/rust-libp2p into and-behav…

9420b85

…iour

jxs added 2 commits January 30, 2023 22:56

remove protocol::Identify,

a0464a3

use ReadyUpgrade for Handler::InboundProtocol

remove protocol::Push<Inbound> and Push<Outbound>,

2c9ac06

use ReadyUpgrade for Handler::OutboundProtocol.

jxs added 3 commits February 6, 2023 11:35

Merge branch 'master' of github.com:libp2p/rust-libp2p into and-behav…

e49dd9b

…iour

Revert "remove protocol::Push<Inbound> and Push<Outbound>,"

77718ac

This reverts commit 2c9ac06.

Revert "remove protocol::Identify,"

d7f73c0

This reverts commit a0464a3.

thomaseizinger requested changes Feb 7, 2023

View reviewed changes

jxs closed this Feb 16, 2023

thomaseizinger mentioned this pull request Jun 15, 2023

swarm/src/behaviour: Add AndBehaviour #2719

Closed

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

feat(swarm): Add AndBehaviour #3366

feat(swarm): Add AndBehaviour #3366

jxs commented Jan 21, 2023 •

edited

Loading

thomaseizinger commented Jan 21, 2023

jxs commented Jan 23, 2023 •

edited

Loading

mergify bot commented Jan 23, 2023

thomaseizinger commented Jan 23, 2023

mergify bot commented Jan 24, 2023

mxinden left a comment

mxinden Jan 26, 2023

jxs Jan 27, 2023

mxinden Jan 26, 2023

jxs Jan 27, 2023

mxinden Jan 26, 2023

jxs Jan 27, 2023

thomaseizinger commented Jan 26, 2023

elenaf9 Jan 27, 2023

mxinden Jan 27, 2023

jxs Jan 27, 2023

elenaf9 Jan 27, 2023

thomaseizinger Jan 31, 2023

jxs commented Jan 27, 2023

jxs commented Jan 27, 2023

mergify bot commented Feb 1, 2023

thomaseizinger left a comment

mergify bot commented Feb 14, 2023

		@@ -1,9 +1,14 @@
		# 0.32.0 [unreleased]

		- Fix `NetworkBehaviour` Derive macro for generic types when `out_event` was not provided. Previously The enum generated

		@@ -1,5 +1,10 @@
		# 0.42.0 [unreleased]

		- Add `And` struct that combines two `NetworkBehaviour` implementations. Helfpful for when one wants

feat(swarm): Add AndBehaviour #3366

feat(swarm): Add AndBehaviour #3366

Conversation

jxs commented Jan 21, 2023 • edited Loading

Description

Notes

Links to any relevant issues

Open Questions

Change checklist

thomaseizinger commented Jan 21, 2023

jxs commented Jan 23, 2023 • edited Loading

mergify bot commented Jan 23, 2023

thomaseizinger commented Jan 23, 2023

mergify bot commented Jan 24, 2023

mxinden left a comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

thomaseizinger commented Jan 26, 2023

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

jxs commented Jan 27, 2023

jxs commented Jan 27, 2023

mergify bot commented Feb 1, 2023

thomaseizinger left a comment

Choose a reason for hiding this comment

mergify bot commented Feb 14, 2023

jxs commented Jan 21, 2023 •

edited

Loading

jxs commented Jan 23, 2023 •

edited

Loading