refactor(network): simplify local state mini-protocol implementation (#…

…326)

examples/n2c-miniprotocols/src/main.rs

@@ -1,19 +1,30 @@
 use pallas::network::{
     facades::NodeClient,
-    miniprotocols::{chainsync, localstate, Point, MAINNET_MAGIC},
+    miniprotocols::{chainsync, localstate::queries_v16, Point, PRE_PRODUCTION_MAGIC},
 };
 use tracing::info;
 
 async fn do_localstate_query(client: &mut NodeClient) {
-    client.statequery().acquire(None).await.unwrap();
+    let client = client.statequery();
 
-    let result = client
-        .statequery()
-        .query(localstate::queries::Request::GetSystemStart)
+    client.acquire(None).await.unwrap();
+
+    let result = queries_v16::get_chain_point(client).await.unwrap();
+    info!("result: {:?}", result);
+
+    let result = queries_v16::get_system_start(client).await.unwrap();
+    info!("result: {:?}", result);
+
+    let era = queries_v16::get_current_era(client).await.unwrap();
+    info!("result: {:?}", era);
+
+    let result = queries_v16::get_block_epoch_number(client, era)
         .await
         .unwrap();
 
-    info!("system start result: {:?}", result);
+    info!("result: {:?}", result);
+
+    client.send_release().await.unwrap();
 }
 
 async fn do_chainsync(client: &mut NodeClient) {
@@ -43,6 +54,10 @@ async fn do_chainsync(client: &mut NodeClient) {
     }
 }
 
+// change the following to match the Cardano node socket in your local
+// environment
+const SOCKET_PATH: &str = "/tmp/node.socket";
+
 #[cfg(target_family = "unix")]
 #[tokio::main]
 async fn main() {
@@ -55,15 +70,7 @@ async fn main() {
 
     // we connect to the unix socket of the local node. Make sure you have the right
     // path for your environment
-    let socket_path = "/tmp/node.socket";
-
-    // we connect to the unix socket of the local node and perform a handshake query
-    let version_table = NodeClient::handshake_query(socket_path, MAINNET_MAGIC)
-        .await
-        .unwrap();
-    info!("handshake query result: {:?}", version_table);
-
-    let mut client = NodeClient::connect(socket_path, MAINNET_MAGIC)
+    let mut client = NodeClient::connect(SOCKET_PATH, PRE_PRODUCTION_MAGIC)
         .await
         .unwrap();
 
@@ -75,7 +82,6 @@ async fn main() {
 }
 
 #[cfg(not(target_family = "unix"))]
-
 fn main() {
     panic!("can't use n2c unix socket on non-unix systems");
 }

pallas-network/src/facades.rs

@@ -282,7 +282,7 @@ impl NodeServer {
                 plexer_handle,
                 version: ver,
                 chainsync: server_cs,
-                statequery: server_sq
+                statequery: server_sq,
             })
         } else {
             plexer_handle.abort();

pallas-network/src/miniprotocols/localstate/client.rs

@@ -1,28 +1,34 @@
+use pallas_codec::utils::AnyCbor;
 use std::fmt::Debug;
-
-use pallas_codec::Fragment;
-
-use std::marker::PhantomData;
 use thiserror::*;
 
-use super::{AcquireFailure, Message, Query, State};
+use super::{AcquireFailure, Message, State};
 use crate::miniprotocols::Point;
 use crate::multiplexer;
 
 #[derive(Error, Debug)]
 pub enum ClientError {
     #[error("attempted to receive message while agency is ours")]
     AgencyIsOurs,
+
     #[error("attempted to send message while agency is theirs")]
     AgencyIsTheirs,
+
     #[error("inbound message is not valid for current state")]
     InvalidInbound,
+
     #[error("outbound message is not valid for current state")]
     InvalidOutbound,
+
     #[error("failure acquiring point, not found")]
     AcquirePointNotFound,
+
     #[error("failure acquiring point, too old")]
     AcquirePointTooOld,
+
+    #[error("failure decoding CBOR data")]
+    InvalidCbor(pallas_codec::minicbor::decode::Error),
+
     #[error("error while sending or receiving data through the channel")]
     Plexer(multiplexer::Error),
 }
@@ -36,22 +42,11 @@ impl From<AcquireFailure> for ClientError {
     }
 }
 
-pub struct GenericClient<Q>(State, multiplexer::ChannelBuffer, PhantomData<Q>)
-where
-    Q: Query,
-    Message<Q>: Fragment;
+pub struct GenericClient(State, multiplexer::ChannelBuffer);
 
-impl<Q> GenericClient<Q>
-where
-    Q: Query,
-    Message<Q>: Fragment,
-{
+impl GenericClient {
     pub fn new(channel: multiplexer::AgentChannel) -> Self {
-        Self(
-            State::Idle,
-            multiplexer::ChannelBuffer::new(channel),
-            PhantomData {},
-        )
+        Self(State::Idle, multiplexer::ChannelBuffer::new(channel))
     }
 
     pub fn state(&self) -> &State {
@@ -87,7 +82,7 @@ where
         }
     }
 
-    fn assert_outbound_state(&self, msg: &Message<Q>) -> Result<(), ClientError> {
+    fn assert_outbound_state(&self, msg: &Message) -> Result<(), ClientError> {
         match (&self.0, msg) {
             (State::Idle, Message::Acquire(_)) => Ok(()),
             (State::Idle, Message::Done) => Ok(()),
@@ -98,7 +93,7 @@ where
         }
     }
 
-    fn assert_inbound_state(&self, msg: &Message<Q>) -> Result<(), ClientError> {
+    fn assert_inbound_state(&self, msg: &Message) -> Result<(), ClientError> {
         match (&self.0, msg) {
             (State::Acquiring, Message::Acquired) => Ok(()),
             (State::Acquiring, Message::Failure(_)) => Ok(()),
@@ -107,15 +102,18 @@ where
         }
     }
 
-    pub async fn send_message(&mut self, msg: &Message<Q>) -> Result<(), ClientError> {
+    pub async fn send_message(&mut self, msg: &Message) -> Result<(), ClientError> {
         self.assert_agency_is_ours()?;
         self.assert_outbound_state(msg)?;
-        self.1.send_msg_chunks(msg).await.map_err(ClientError::Plexer)?;
+        self.1
+            .send_msg_chunks(msg)
+            .await
+            .map_err(ClientError::Plexer)?;
 
         Ok(())
     }
 
-    pub async fn recv_message(&mut self) -> Result<Message<Q>, ClientError> {
+    pub async fn recv_message(&mut self) -> Result<Message, ClientError> {
         self.assert_agency_is_theirs()?;
         let msg = self.1.recv_full_msg().await.map_err(ClientError::Plexer)?;
         self.assert_inbound_state(&msg)?;
@@ -124,31 +122,31 @@ where
     }
 
     pub async fn send_acquire(&mut self, point: Option<Point>) -> Result<(), ClientError> {
-        let msg = Message::<Q>::Acquire(point);
+        let msg = Message::Acquire(point);
         self.send_message(&msg).await?;
         self.0 = State::Acquiring;
 
         Ok(())
     }
 
     pub async fn send_reacquire(&mut self, point: Option<Point>) -> Result<(), ClientError> {
-        let msg = Message::<Q>::ReAcquire(point);
+        let msg = Message::ReAcquire(point);
         self.send_message(&msg).await?;
         self.0 = State::Acquiring;
 
         Ok(())
     }
 
     pub async fn send_release(&mut self) -> Result<(), ClientError> {
-        let msg = Message::<Q>::Release;
+        let msg = Message::Release;
         self.send_message(&msg).await?;
         self.0 = State::Idle;
 
         Ok(())
     }
 
     pub async fn send_done(&mut self) -> Result<(), ClientError> {
-        let msg = Message::<Q>::Done;
+        let msg = Message::Done;
         self.send_message(&msg).await?;
         self.0 = State::Done;
 
@@ -174,28 +172,38 @@ where
         self.recv_while_acquiring().await
     }
 
-    pub async fn send_query(&mut self, request: Q::Request) -> Result<(), ClientError> {
-        let msg = Message::<Q>::Query(request);
+    pub async fn send_query(&mut self, request: AnyCbor) -> Result<Message, ClientError> {
+        let msg = Message::Query(request);
         self.send_message(&msg).await?;
         self.0 = State::Querying;
 
-        Ok(())
+        Ok(msg)
     }
 
-    pub async fn recv_while_querying(&mut self) -> Result<Q::Response, ClientError> {
+    pub async fn recv_while_querying(&mut self) -> Result<AnyCbor, ClientError> {
         match self.recv_message().await? {
-            Message::Result(x) => {
+            Message::Result(result) => {
                 self.0 = State::Acquired;
-                Ok(x)
+                Ok(result)
             }
             _ => Err(ClientError::InvalidInbound),
         }
     }
 
-    pub async fn query(&mut self, request: Q::Request) -> Result<Q::Response, ClientError> {
+    pub async fn query_any(&mut self, request: AnyCbor) -> Result<AnyCbor, ClientError> {
         self.send_query(request).await?;
         self.recv_while_querying().await
     }
+
+    pub async fn query<Q, R>(&mut self, request: Q) -> Result<R, ClientError>
+    where
+        Q: pallas_codec::minicbor::Encode<()>,
+        for<'b> R: pallas_codec::minicbor::Decode<'b, ()>,
+    {
+        let request = AnyCbor::from_encode(request);
+        let response = self.query_any(request).await?;
+        response.into_decode().map_err(ClientError::InvalidCbor)
+    }
 }
 
-pub type Client = GenericClient<super::queries::QueryV16>;
+pub type Client = GenericClient;

pallas-network/src/miniprotocols/localstate/codec.rs

@@ -1,6 +1,6 @@
 use pallas_codec::minicbor::{decode, encode, Decode, Encode, Encoder};
 
-use super::{AcquireFailure, Message, Query};
+use super::{AcquireFailure, Message};
 
 impl Encode<()> for AcquireFailure {
     fn encode<W: encode::Write>(
@@ -36,12 +36,7 @@ impl<'b> Decode<'b, ()> for AcquireFailure {
     }
 }
 
-impl<Q> Encode<()> for Message<Q>
-where
-    Q: Query,
-    Q::Request: Encode<()>,
-    Q::Response: Encode<()>,
-{
+impl Encode<()> for Message {
     fn encode<W: encode::Write>(
         &self,
         e: &mut Encoder<W>,
@@ -97,12 +92,7 @@ where
     }
 }
 
-impl<'b, Q> Decode<'b, ()> for Message<Q>
-where
-    Q: Query,
-    Q::Request: Decode<'b, ()>,
-    Q::Response: Decode<'b, ()>,
-{
+impl<'b> Decode<'b, ()> for Message {
     fn decode(
         d: &mut pallas_codec::minicbor::Decoder<'b>,
         _ctx: &mut (),

pallas-network/src/miniprotocols/localstate/mod.rs

@@ -1,9 +1,10 @@
 mod client;
 mod codec;
 mod protocol;
-pub mod queries;
 mod server;
 
+pub mod queries_v16;
+
 pub use client::*;
 pub use codec::*;
 pub use protocol::*;

pallas-network/src/miniprotocols/localstate/protocol.rs

@@ -1,5 +1,7 @@
 use std::fmt::Debug;
 
+use pallas_codec::utils::AnyCbor;
+
 use crate::miniprotocols::Point;
 
 #[derive(Debug, PartialEq, Eq, Clone)]
@@ -17,18 +19,13 @@ pub enum AcquireFailure {
     PointNotOnChain,
 }
 
-pub trait Query: Debug {
-    type Request: Clone + Debug;
-    type Response: Clone + Debug;
-}
-
 #[derive(Debug)]
-pub enum Message<Q: Query> {
+pub enum Message {
     Acquire(Option<Point>),
     Failure(AcquireFailure),
     Acquired,
-    Query(Q::Request),
-    Result(Q::Response),
+    Query(AnyCbor),
+    Result(AnyCbor),
     ReAcquire(Option<Point>),
     Release,
     Done,