From 3147eb90ead9e156a27b88aa5a0838f9d4b6e92f Mon Sep 17 00:00:00 2001
From: Soares Chen <soares.chen@gmail.com>
Date: Mon, 14 Jun 2021 15:05:17 +0200
Subject: [PATCH] Use gRPC to query connection end (#1048)

---
 relayer/src/chain/cosmos.rs | 56 ++++++++++++++++++++++++++++++++++---
 relayer/src/connection.rs   |  8 +++---
 relayer/src/error.rs        |  3 ++
 3 files changed, 59 insertions(+), 8 deletions(-)

diff --git a/relayer/src/chain/cosmos.rs b/relayer/src/chain/cosmos.rs
index 1636c9dce0..f5e0a9df91 100644
--- a/relayer/src/chain/cosmos.rs
+++ b/relayer/src/chain/cosmos.rs
@@ -18,6 +18,7 @@ use tendermint_rpc::query::Query;
 use tendermint_rpc::{endpoint::broadcast::tx_commit::Response, Client, HttpClient, Order};
 use tokio::runtime::Runtime as TokioRuntime;
 use tonic::codegen::http::Uri;
+use tonic::Code;
 
 use ibc::downcast;
 use ibc::events::{from_tx_response_event, IbcEvent};
@@ -751,11 +752,58 @@ impl Chain for CosmosSdkChain {
         connection_id: &ConnectionId,
         height: ICSHeight,
     ) -> Result<ConnectionEnd, Error> {
-        let res = self.query(Path::Connections(connection_id.clone()), height, false)?;
-        let connection_end = ConnectionEnd::decode_vec(&res.value)
-            .map_err(|e| Kind::Query(format!("connection '{}'", connection_id)).context(e))?;
+        async fn do_query_connection(
+            chain: &CosmosSdkChain,
+            connection_id: &ConnectionId,
+            height: ICSHeight,
+        ) -> Result<ConnectionEnd, Error> {
+            use ibc_proto::ibc::core::connection::v1 as connection;
+            use tonic::{metadata::MetadataValue, IntoRequest};
+
+            let mut client =
+                connection::query_client::QueryClient::connect(chain.grpc_addr.clone())
+                    .await
+                    .map_err(|e| Kind::Grpc.context(e))?;
+
+            let mut request = connection::QueryConnectionRequest {
+                connection_id: connection_id.to_string(),
+            }
+            .into_request();
+
+            let height_param = MetadataValue::from_str(&height.revision_height.to_string())
+                .map_err(|e| Kind::Grpc.context(e))?;
+
+            request
+                .metadata_mut()
+                .insert("x-cosmos-block-height", height_param);
+
+            let response = client.connection(request).await.map_err(|e| {
+                if e.code() == Code::NotFound {
+                    Kind::ConnectionNotFound(connection_id.clone()).into()
+                } else {
+                    Kind::Grpc.context(e)
+                }
+            })?;
+
+            match response.into_inner().connection {
+                Some(raw_connection) => {
+                    let connection_end = raw_connection
+                        .try_into()
+                        .map_err(|e| Kind::Grpc.context(e))?;
+
+                    Ok(connection_end)
+                }
+                None => {
+                    // When no connection is found, the GRPC call itself should return
+                    // the NotFound error code. Nevertheless even if the call is successful,
+                    // the connection field may not be present, because in protobuf3
+                    // everything is optional.
+                    Err(Kind::ConnectionNotFound(connection_id.clone()).into())
+                }
+            }
+        }
 
-        Ok(connection_end)
+        self.block_on(async { do_query_connection(self, connection_id, height).await })
     }
 
     fn query_connection_channels(
diff --git a/relayer/src/connection.rs b/relayer/src/connection.rs
index b9fb549418..9fa52fdc8b 100644
--- a/relayer/src/connection.rs
+++ b/relayer/src/connection.rs
@@ -17,7 +17,6 @@ use ibc::ics03_connection::msgs::conn_open_try::MsgConnectionOpenTry;
 use ibc::ics24_host::identifier::{ChainId, ClientId, ConnectionId};
 use ibc::timestamp::ZERO_DURATION;
 use ibc::tx_msg::Msg;
-use ibc::Height as ICSHeight;
 
 use crate::chain::handle::ChainHandle;
 use crate::error::Error;
@@ -389,7 +388,7 @@ impl Connection {
         // Retrieve existing connection if any
         let dst_connection = self
             .dst_chain()
-            .query_connection(self.dst_connection_id(), ICSHeight::default())
+            .query_connection(self.dst_connection_id(), Height::zero())
             .map_err(|e| ConnectionError::QueryError(self.dst_chain().id(), e))?;
 
         // Check if a connection is expected to exist on destination chain
@@ -494,7 +493,7 @@ impl Connection {
     pub fn build_conn_try(&self) -> Result<Vec<Any>, ConnectionError> {
         let src_connection = self
             .src_chain()
-            .query_connection(self.src_connection_id(), ICSHeight::default())
+            .query_connection(self.src_connection_id(), Height::zero())
             .map_err(|e| ConnectionError::QueryError(self.src_chain().id(), e))?;
 
         // TODO - check that the src connection is consistent with the try options
@@ -626,7 +625,7 @@ impl Connection {
 
         let src_connection = self
             .src_chain()
-            .query_connection(self.src_connection_id(), ICSHeight::default())
+            .query_connection(self.src_connection_id(), Height::zero())
             .map_err(|e| ConnectionError::QueryError(self.src_chain().id(), e))?;
 
         // TODO - check that the src connection is consistent with the ack options
@@ -724,6 +723,7 @@ impl Connection {
             .src_chain()
             .query_latest_height()
             .map_err(|e| ConnectionError::QueryError(self.src_chain().id(), e))?;
+
         let _src_connection = self
             .src_chain()
             .query_connection(self.src_connection_id(), query_height)
diff --git a/relayer/src/error.rs b/relayer/src/error.rs
index cef2d190f3..26c6103275 100644
--- a/relayer/src/error.rs
+++ b/relayer/src/error.rs
@@ -82,6 +82,9 @@ pub enum Kind {
     #[error("Failed to create client {0}")]
     CreateClient(String),
 
+    #[error("Connection not found: {0}")]
+    ConnectionNotFound(ConnectionId),
+
     /// Common failures to all connection messages
     #[error("Failed to build conn open message {0}: {1}")]
     ConnOpen(ConnectionId, String),