Macro for composing custom message handlers #1832
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One alternative to discuss is going the macro-only approach and actually taking a patern vs a min/max: #1813 (comment) I don't have a strong opinion, just throwing it out there. |
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Nice! I think we should restrict the macro a bit to also implement CustomMessageHandler on the generated struct. |
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Codecov ReportBase: 87.33% // Head: 87.92% // Increases project coverage by
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LGTM |
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Making sure I'm understanding this PR correctly: currently PeerManager is created with a single CustomMessageHandler that handles custom lightning messages for application specific/experimental messages. You can implement CustomMessageHandler on a specific message type, but if you want to handle multiple custom messages, it's a lot of boilerplate to combine the different handlers into one (which is required to handle multiple custom messages)--and this macro makes this easy. If I'm getting that all right, this seems really clean!
Out of scope for this PR, but wanted to mention while I was going through this code it took me a bit to realize how CustomMessageHandler was used in PeerManager, as there's not much mention of each other in either of their respective docs. In hindsight it seems sorta obvious but that was something I ran into.
| //! composite_custom_message_handler!( | ||
| //! pub struct FooBarBazHandler { | ||
| //! foo_bar: FooBarHandler, | ||
| //! baz: BazHandler, | ||
| //! } | ||
| //! | ||
| //! pub enum FooBarBazMessage { | ||
| //! FooBar(foo_bar_type_ids!()), | ||
| //! Baz(baz_type_id!()), | ||
| //! } | ||
| //! ); |
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Is there a reason someone would opt for using the macro multiple times like this as opposed to just listing each message + handler in one? i.e.
composite_custom_message_handler!(
pub struct FooBarBazHandler {
foo: FooHandler,
bar: BarHandler,
baz: BazHandler,
}
...
}
Also is there significance to the foo_bar_type_ids being the | of the two type ids or was that mostly arbitrary? Otherwise, I thought the FooBar example was very helpful/straightforward!
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Is there a reason someone would opt for using the macro multiple times like this as opposed to just listing each message + handler in one? i.e.
composite_custom_message_handler!( pub struct FooBarBazHandler { foo: FooHandler, bar: BarHandler, baz: BazHandler, } ... }
That is also possible, though the example is meant to demonstrate arbitrary composition. This may be useful when FooBarHandler is defined in one crate and you want to use it along with BazHandler in your own crate. I've added some comments to the example to clarify this use case.
Also is there significance to the
foo_bar_type_idsbeing the|of the two type ids or was that mostly arbitrary? Otherwise, I thought theFooBarexample was very helpful/straightforward!
Yes, the macro matcher $pattern uses a pat specifier, meaning it can be anything rust considers a pattern, including the composition of patterns using |.
https://doc.rust-lang.org/reference/patterns.html
Someone using the macro could use a range of type ids instead, e.g., 32768..=32769. Though the | approach is preferred for the reason given in the macro's docs.
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That is also possible, though the example is meant to demonstrate arbitrary composition. This may be useful when FooBarHandler is defined in one crate and you want to use it along with BazHandler in your own crate. I've added some comments to the example to clarify this use case.
Ah makes sense!
Yes, the macro matcher
$patternuses apatspecifier, meaning it can be anything rust considers a pattern, including the composition of patterns using|.
Ohh I see I didn't realize it was being used as a pattern I thought it was doing a bitwise OR of the two type ids, that's cool.
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Thanks for the review! All good feedback.
Correct!
Hmm... yeah, those docs could use some work. I've added a commit that re-writes them. |
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| //! fn type_id(&self) -> u16 { foo_type_id!() } | ||
| //! } | ||
| //! impl Writeable for Foo { | ||
| //! // ... |
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So, I believe all (most?) of our doctests use spaces. IIRC, there was some weirdness around the leading "//! " and the first tab not indenting enough. Especially, if the space after the comment was skipped in lieu of the first tab.
| //! [BOLT 1]: https://github.com/lightning/bolts/blob/master/01-messaging.md | ||
| //! [`CustomMessageHandler`]: crate::lightning::ln::peer_handler::CustomMessageHandler | ||
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| #![doc(test(no_crate_inject, attr(deny(warnings))))] |
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What is a no_crate_inject and why are we denying compilation warnings?
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no_crate_inject is needed otherwise we can't add #[macro_use] on the crate in the doc test.
For warnings, I was testing out unreachable patterns in the doc test, so needed that for it fail. I can remove it now, I suppose.
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Yea, I just generally worry about deny(warnings) cause that means CI will start failing on a new rustc without us touching anything. We'll fix warnings when we find them.
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FWIW, this only affects doc tests.
| //! pub struct Baz; | ||
| //! | ||
| //! macro_rules! baz_type_id { | ||
| //! () => { 32770 } |
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Would be cool to demonstrate baz supporting two different message ids internally.
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Probably better left for CustomMessageHandler docs?
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Well with the macro_rules-specific stuff for this crate.
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Like what is done using the FooBarHandler? I thought you had meant showing a leaf handler handling more than one message.
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Right, I did mean a leaf handler handling more than one message feeding into one MessageHandler. I guess it doesn't matter, though, as long as the documentation mentions that you can do any pattern (which it does) and maybe mention in the example that they don't have to be in different crate(s).
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Needs test but can be saved for a follow-up. |
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Test or not we should add something that hits this code in CI. |
Ah, sorry! Misread your comment. Let's see if the latest commit triggers testing on the crate. |
| @@ -11,6 +11,7 @@ members = [ | |||
| ] | |||
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| exclude = [ | |||
| "lightning-custom-message", | |||
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Any reason it's excluded?
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Trying to compile using cargo +1.41.1 check gives:
error: failed to parse manifest at `/Users/jkczyz/src/rust-lightning/lightning-custom-message/Cargo.toml`
Caused by:
failed to parse the `edition` key
Caused by:
supported edition values are `2015` or `2018`, but `2021` is unknown
But after rebasing, it looks like that's also a problem for one one of lightning-transaction-sync's dependencies, as well. I guess we just can't build the entire workspace with an older rust version now?
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Ah, I guess CI doesn't try to build the workspace at all then since it's passing without excluding lightning-transaction-sync. We probably shouldn't break the default way to build for users on our MSRV, so we should exclude lightning-transaction-sync as well.
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Ok, correction, the above command also doesn't work because lightning-net-tokio requires a higher version. So moving lightning-custom-message back into the members should be fine.
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Spoke to soon. CI is unhappy because of the edition:
error: failed to parse manifest at `/home/runner/work/rust-lightning/rust-lightning/lightning-custom-message/Cargo.toml`
Caused by:
failed to parse the `edition` key
Caused by:
supported edition values are `2015` or `2018, but `2021` is unknown
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BOLT 1 specifies a custom message type range for use with experimental or application-specific messages. While a `CustomMessageHandler` can be defined to support more than one message type, defining such a handler requires a significant amount of boilerplate and can be error prone. Add a crate exporting a `composite_custom_message_handler` macro for easily composing pre-defined custom message handlers. The resulting handler can be further composed with other custom message handlers using the same macro. This requires a separate crate since the macro needs to support "or" patterns in macro_rules, which is only available in edition 2021. https://doc.rust-lang.org/edition-guide/rust-2021/or-patterns-macro-rules.html Otherwise, a crate defining a handler for a set of custom messages could not easily be reused with another custom message handler. Doing so would require explicitly duplicating the reused handlers type ids, but those may change when the crate is updated.
These are seen in newer versions of rustc.
Documentation for CustomMessageHandler wasn't clear how it is related to PeerManager and contained some grammatical and factual errors. Re-write the docs and link to the lightning_custom_message crate.
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0.0.114 - Mar 3, 2023 - "Faster Async BOLT12 Retries" API Updates =========== * `InvoicePayer` has been removed and its features moved directly into `ChannelManager`. As such it now requires a simplified `Router` and supports `send_payment_with_retry` (and friends). `ChannelManager::retry_payment` was removed in favor of the automated retries. Invoice payment utilities in `lightning-invoice` now call the new code (lightningdevkit#1812, lightningdevkit#1916, lightningdevkit#1929, lightningdevkit#2007, etc). * `Sign`/`BaseSign` has been renamed `ChannelSigner`, with `EcdsaChannelSigner` split out in anticipation of future schnorr/taproot support (lightningdevkit#1967). * The catch-all `KeysInterface` was split into `EntropySource`, `NodeSigner`, and `SignerProvider`. `KeysManager` implements all three (lightningdevkit#1910, lightningdevkit#1930). * `KeysInterface::get_node_secret` is now `KeysManager::get_node_secret_key` and is no longer required for external signers (lightningdevkit#1951, lightningdevkit#2070). * A `lightning-transaction-sync` crate has been added which implements keeping LDK in sync with the chain via an esplora server (lightningdevkit#1870). Note that it can only be used on nodes that *never* ran a previous version of LDK. * `Score` is updated in `BackgroundProcessor` instead of via `Router` (lightningdevkit#1996). * `ChainAccess::get_utxo` (now `UtxoAccess`) can now be resolved async (lightningdevkit#1980). * BOLT12 `Offer`, `InvoiceRequest`, `Invoice` and `Refund` structs as well as associated builders have been added. Such invoices cannot yet be paid due to missing support for blinded path payments (lightningdevkit#1927, lightningdevkit#1908, lightningdevkit#1926). * A `lightning-custom-message` crate has been added to make combining multiple custom messages into one enum/handler easier (lightningdevkit#1832). * `Event::PaymentPathFailure` is now generated for failure to send an HTLC over the first hop on our local channel (lightningdevkit#2014, lightningdevkit#2043). * `lightning-net-tokio` no longer requires an `Arc` on `PeerManager` (lightningdevkit#1968). * `ChannelManager::list_recent_payments` was added (lightningdevkit#1873). * `lightning-background-processor` `std` is now optional in async mode (lightningdevkit#1962). * `create_phantom_invoice` can now be used in `no-std` (lightningdevkit#1985). * The required final CLTV delta on inbound payments is now configurable (lightningdevkit#1878) * bitcoind RPC error code and message are now surfaced in `block-sync` (lightningdevkit#2057). * Get `historical_estimated_channel_liquidity_probabilities` was added (lightningdevkit#1961). * `ChannelManager::fail_htlc_backwards_with_reason` was added (lightningdevkit#1948). * Macros which implement serialization using TLVs or straight writing of struct fields are now public (lightningdevkit#1823, lightningdevkit#1976, lightningdevkit#1977). Backwards Compatibility ======================= * Any inbound payments with a custom final CLTV delta will be rejected by LDK if you downgrade prior to receipt (lightningdevkit#1878). * `Event::PaymentPathFailed::network_update` will always be `None` if an 0.0.114-generated event is read by a prior version of LDK (lightningdevkit#2043). * `Event::PaymentPathFailed::all_paths_removed` will always be false if an 0.0.114-generated event is read by a prior version of LDK. Users who rely on it to determine payment retries should migrate to `Event::PaymentFailed`, in a separate release prior to upgrading to LDK 0.0.114 if downgrading is supported (lightningdevkit#2043). Performance Improvements ======================== * Channel data is now stored per-peer and channel updates across multiple peers can be operated on simultaneously (lightningdevkit#1507). * Routefinding is roughly 1.5x faster (lightningdevkit#1799). * Deserializing a `NetworkGraph` is roughly 6x faster (lightningdevkit#2016). * Memory usage for a `NetworkGraph` has been reduced substantially (lightningdevkit#2040). * `KeysInterface::get_secure_random_bytes` is roughly 200x faster (lightningdevkit#1974). Bug Fixes ========= * Fixed a bug where a delay in processing a `PaymentSent` event longer than the time taken to persist a `ChannelMonitor` update, when occurring immediately prior to a crash, may result in the `PaymentSent` event being lost (lightningdevkit#2048). * Fixed spurious rejections of rapid gossip sync data when the graph has been updated by other means between gossip syncs (lightningdevkit#2046). * Fixed a panic in `KeysManager` when the high bit of `starting_time_nanos` is set (lightningdevkit#1935). * Resolved an issue where the `ChannelManager::get_persistable_update_future` future would fail to wake until a second notification occurs (lightningdevkit#2064). * Resolved a memory leak when using `ChannelManager::send_probe` (lightningdevkit#2037). * Fixed a deadlock on some platforms at least when using async `ChannelMonitor` updating (lightningdevkit#2006). * Removed debug-only assertions which were reachable in threaded code (lightningdevkit#1964). * In some cases when payment sending fails on our local channel retries no longer take the same path and thus never succeed (lightningdevkit#2014). * Retries for spontaneous payments have been fixed (lightningdevkit#2002). * Return an `Err` if `lightning-persister` fails to read the directory listing rather than panicing (lightningdevkit#1943). * `peer_disconnected` will now never be called without `peer_connected` (lightningdevkit#2035) Security ======== 0.0.114 fixes several denial-of-service vulnerabilities which are reachable from untrusted input from channel counterparties or in deployments accepting inbound connections or channels. It also fixes a denial-of-service vulnerability in rare cases in the route finding logic. * The number of pending un-funded channels as well as peers without funded channels is now limited to avoid denial of service (lightningdevkit#1988). * A second `channel_ready` message received immediately after the first could lead to a spurious panic (lightningdevkit#2071). This issue was introduced with 0conf support in LDK 0.0.107. * A division-by-zero issue was fixed in the `ProbabilisticScorer` if the amount being sent (including previous-hop fees) is equal to a channel's capacity while walking the graph (lightningdevkit#2072). The division-by-zero was introduced with historical data tracking in LDK 0.0.112. In total, this release features 130 files changed, 21457 insertions, 10113 deletions in 343 commits from 18 authors, in alphabetical order: * Alec Chen * Allan Douglas R. de Oliveira * Andrei * Arik Sosman * Daniel Granhão * Duncan Dean * Elias Rohrer * Jeffrey Czyz * John Cantrell * Kurtsley * Matt Corallo * Max Fang * Omer Yacine * Valentine Wallace * Viktor Tigerström * Wilmer Paulino * benthecarman * jurvis
Macro for composing custom message handlers BOLT 1 specifies a custom message type range for use with experimental or application-specific messages. While a
CustomMessageHandlercan be defined to support more than one message type, defining such a handler requires a significant amount of boilerplate and can be error prone.Add a crate exporting a
composite_custom_message_handlermacro for easily composing pre-defined custom message handlers. The resulting handler can be further composed with other custom message handlers using the same macro.This requires a separate crate since the macro needs to support "or" patterns in macro_rules, which is only available in edition 2021.
https://doc.rust-lang.org/edition-guide/rust-2021/or-patterns-macro-rules.html
Otherwise, a crate defining a handler for a set of custom messages could not easily be reused with another custom message handler. Doing so would require explicitly duplicating the reused handlers type ids, but those may change when the crate is updated.
Fixes #1813.