light-client: add missing RPC endpoint and extend handler/supervisor (#…

…449)

* WIP: add `LatestStatus` type and a method to the handler

* add `LatestStatus` type and a method to the handler/supervisor and an RPC endpoint

* Actually add the connected nodes

* Add info output and fix main output
 - from `synced to block {} 1234` to `synced to block: 1234`

* Fix some typos while debugging

* Fix #450 🎉 thanks @OStevan 🙏

* add mock test for added rpc end-point

* Refer to additional RPC endpoint in README.md

* Update Changelog

* Fix example in README.md

* Update CHANGES.md

* Fix README.md: Add closing `</details>` for 1st example

* Make all fields but connected_nodes optional

* Always return a status instead

* Fix paste err (thx @xla)

CHANGES.md

@@ -17,10 +17,14 @@
 - Correctly handle blocks marked `Trusted` in accordance with the specification ([#407])
 - Treat `Trusted` status as a special case of `Verified` as per the spec ([#419])
 - Add integration test ([#431])
+- Rework light-node CLI to use `Supervisor` / `Handle` ([#430])
+- Add `latest_status` to the supervisor `Handle` ([#449])
+- Add JSONRPC endpoints to query the light-node ([#363], [#449])  
 
 [#302]: https://github.com/informalsystems/tendermint-rs/pull/302
 [#336]: https://github.com/informalsystems/tendermint-rs/pull/336
 [#360]: https://github.com/informalsystems/tendermint-rs/pull/360
+[#363]: https://github.com/informalsystems/tendermint-rs/pull/363
 [#364]: https://github.com/informalsystems/tendermint-rs/pull/364
 [#365]: https://github.com/informalsystems/tendermint-rs/pull/365
 [#371]: https://github.com/informalsystems/tendermint-rs/pull/371
@@ -32,7 +36,9 @@
 [#403]: https://github.com/informalsystems/tendermint-rs/pull/403
 [#407]: https://github.com/informalsystems/tendermint-rs/pull/407
 [#419]: https://github.com/informalsystems/tendermint-rs/pull/419
+[#430]: https://github.com/informalsystems/tendermint-rs/pull/430
 [#431]: https://github.com/informalsystems/tendermint-rs/pull/431
+[#449]: https://github.com/informalsystems/tendermint-rs/pull/449
 
 [ADR-007]: https://github.com/informalsystems/tendermint-rs/blob/master/docs/architecture/adr-007-light-client-supervisor-ergonomics.md
 

light-client/src/light_client.rs

@@ -88,7 +88,7 @@ impl LightClient {
 
     /// Attempt to update the light client to the highest block of the primary node.
     ///
-    /// Note: This functin delegates the actual work to `verify_to_target`.
+    /// Note: This function delegates the actual work to `verify_to_target`.
     pub fn verify_to_highest(&mut self, state: &mut State) -> Result<LightBlock, Error> {
         let target_block = match self.io.fetch_light_block(self.peer, AtHeight::Highest) {
             Ok(last_block) => last_block,

light-client/src/peer_list.rs

@@ -159,7 +159,7 @@ pub struct PeerListBuilder<T> {
 }
 
 // This instance must be derived manually because the automatically
-// derived instancce constrains T to be Default.
+// derived instance constrains T to be Default.
 // See https://github.com/rust-lang/rust/issues/26925
 impl<T> Default for PeerListBuilder<T> {
     fn default() -> Self {

light-client/src/store/memory.rs

@@ -65,8 +65,8 @@ impl LightStore for MemoryStore {
     fn latest(&self, status: Status) -> Option<LightBlock> {
         self.store
             .iter()
-            .rev()
-            .find(|(_, e)| e.status == status)
+            .filter(|(_, e)| e.status == status)
+            .max_by_key(|(&height, _)| height)
             .map(|(_, e)| e.light_block.clone())
     }
 

light-client/src/store/sled.rs

@@ -72,7 +72,9 @@ impl LightStore for SledStore {
     }
 
     fn latest(&self, status: Status) -> Option<LightBlock> {
-        self.db(status).iter(&self.db).next_back()
+        self.db(status)
+            .iter(&self.db)
+            .max_by(|first, second| first.height().cmp(&second.height()))
     }
 
     fn all(&self, status: Status) -> Box<dyn Iterator<Item = LightBlock>> {

light-client/src/supervisor.rs

@@ -9,14 +9,19 @@ use crate::fork_detector::{Fork, ForkDetection, ForkDetector};
 use crate::light_client::LightClient;
 use crate::peer_list::PeerList;
 use crate::state::State;
-use crate::types::{Height, LightBlock, PeerId, Status};
+use crate::types::{Height, LatestStatus, LightBlock, PeerId, Status};
+use tendermint::lite::{Header, ValidatorSet};
 
 pub trait Handle {
     /// Get latest trusted block from the [`Supervisor`].
     fn latest_trusted(&self) -> Result<Option<LightBlock>, Error> {
         todo!()
     }
 
+    fn latest_status(&self) -> Result<LatestStatus, Error> {
+        todo!()
+    }
+
     /// Verify to the highest block.
     fn verify_to_highest(&self) -> Result<LightBlock, Error> {
         todo!()
@@ -45,6 +50,8 @@ enum HandleInput {
     VerifyToTarget(Height, channel::Sender<Result<LightBlock, Error>>),
     /// Get the latest trusted block.
     LatestTrusted(channel::Sender<Option<LightBlock>>),
+    /// Get the current status of the LightClient
+    GetStatus(channel::Sender<LatestStatus>),
 }
 
 /// A light client `Instance` packages a `LightClient` together with its `State`.
@@ -166,6 +173,25 @@ impl Supervisor {
         self.verify(None)
     }
 
+    /// Return latest trusted status summary.
+    fn latest_status(&mut self) -> LatestStatus {
+        let latest_trusted = self.peers.primary().latest_trusted();
+        let mut connected_nodes: Vec<PeerId> = Vec::new();
+        connected_nodes.push(self.peers.primary_id());
+        connected_nodes.append(&mut self.peers.witnesses_ids().iter().copied().collect());
+
+        match latest_trusted {
+            Some(trusted) => LatestStatus::new(
+                Some(trusted.signed_header.header.height()),
+                Some(trusted.signed_header.header.hash()),
+                Some(trusted.next_validators.hash()),
+                connected_nodes,
+            ),
+            // only return connected nodes to see what is going on:
+            None => LatestStatus::new(None, None, None, connected_nodes),
+        }
+    }
+
     /// Verify to the block at the given height.
     pub fn verify_to_target(&mut self, height: Height) -> Result<LightBlock, Error> {
         self.verify(Some(height))
@@ -322,6 +348,10 @@ impl Supervisor {
                     let outcome = self.verify_to_highest();
                     sender.send(outcome).map_err(ErrorKind::from)?;
                 }
+                HandleInput::GetStatus(sender) => {
+                    let outcome = self.latest_status();
+                    sender.send(outcome).map_err(ErrorKind::from)?;
+                }
             }
         }
     }
@@ -363,6 +393,14 @@ impl Handle for SupervisorHandle {
         Ok(receiver.recv().map_err(ErrorKind::from)?)
     }
 
+    fn latest_status(&self) -> Result<LatestStatus, Error> {
+        let (sender, receiver) = channel::bounded::<LatestStatus>(1);
+        self.sender
+            .send(HandleInput::GetStatus(sender))
+            .map_err(ErrorKind::from)?;
+        Ok(receiver.recv().map_err(ErrorKind::from)?)
+    }
+
     fn verify_to_highest(&self) -> Result<LightBlock, Error> {
         self.verify(HandleInput::VerifyToHighest)
     }

light-client/src/types.rs

@@ -116,6 +116,38 @@ impl LightBlock {
     }
 }
 
+/// Contains the local status information, like the latest height, latest block and valset hashes,
+/// list of of connected full nodes (primary and witnesses).
+#[derive(Clone, Debug, Display, PartialEq, Serialize, Deserialize)]
+#[display(fmt = "{:?}", self)]
+pub struct LatestStatus {
+    /// The latest height we are trusting.
+    pub height: Option<Height>,
+    /// The latest block hash we are trusting.
+    pub block_hash: Option<Hash>,
+    /// The latest validator set we are trusting.
+    /// Note that this potentially did not yet sign a header yet.
+    pub valset_hash: Option<Hash>,
+    /// The list of fullnodes we are connected to, primary and witnesses.
+    pub connected_nodes: Vec<PeerId>,
+}
+
+impl LatestStatus {
+    pub fn new(
+        height: Option<u64>,
+        block_hash: Option<Hash>,
+        valset_hash: Option<Hash>,
+        connected_nodes: Vec<PeerId>,
+    ) -> Self {
+        LatestStatus {
+            height,
+            block_hash,
+            valset_hash,
+            connected_nodes,
+        }
+    }
+}
+
 #[cfg(test)]
 mod tests {
 

light-node/README.md

@@ -106,8 +106,42 @@ $ curl localhost:8888 -X POST -H 'Content-Type: application/json' \
   -d '{"jsonrpc": "2.0", "method": "state", "id": 1}' | jq
 ```
 
+Or you can query a shorter summary via the `/status` endpoint:
+```
+$  curl localhost:8888 -X POST -H 'Content-Type: application/json'\                                                                        15:58:52
+                                                             -d '{"jsonrpc": "2.0", "method": "status", "id": 1}' | jq
+
+```
+
+<details>
+  <summary><b>Click here</b> to see an example for expected output for the status endpoint:</summary>
+
+```
+$ curl localhost:8888 -X POST -H 'Content-Type: application/json' \
+  -d '{"jsonrpc": "2.0", "method": "status", "id": 1}' | jq
+  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
+                                 Dload  Upload   Total   Spent    Left  Speed
+100   364  100   317  100    47   1843    273 --:--:-- --:--:-- --:--:--  2104
+```
+```json
+{
+  "jsonrpc": "2.0",
+  "result": {
+    "block_hash": "ED745723430944215F65ED78AD7DF9ED0AA8A2A3B465BF421E0BAF66AA55AA08",
+    "connected_nodes": [
+      "BADFADAD0BEFEEDC0C0ADEADBEEFC0FFEEFACADE",
+      "CEFEEDBADFADAD0C0CEEFACADE0ADEADBEEFC0FF"
+    ],
+    "height": 3850,
+    "valset_hash": "74F2AC2B6622504D08DD2509E28CE731985CFE4D133C9DB0CB85763EDCA95AA3"
+  },
+  "id": 1
+}
+```
+</details>
+
 <details>
-  <summary><b>Click here</b> to see an example for expected output:</summary>
+  <summary><b>Click here</b> to see an example for expected output for the state endpoint:</summary>
 
 Command:  
   ```

light-node/src/commands/start.rs

@@ -35,7 +35,6 @@ use tendermint_light_client::store::sled::SledStore;
 use tendermint_light_client::store::LightStore;
 use tendermint_light_client::supervisor::Handle;
 use tendermint_light_client::supervisor::{Instance, Supervisor};
-use tendermint_light_client::types::Status;
 
 /// `start` subcommand
 ///
@@ -70,7 +69,7 @@ impl Runnable for StartCmd {
             loop {
                 match handle.verify_to_highest() {
                     Ok(light_block) => {
-                        status_info!("synced to block {}", light_block.height().to_string());
+                        status_info!("synced to block:", light_block.height().to_string());
                     }
                     Err(err) => {
                         status_err!("sync failed: {}", err);
@@ -157,6 +156,7 @@ impl StartCmd {
         let laddr = app_config().rpc_config.listen_addr;
         // TODO(liamsi): figure out how to handle the potential error on run
         std::thread::spawn(move || rpc::run(server, &laddr.to_string()));
+        status_info!("started RPC server:", laddr.to_string());
     }
 }
 
@@ -189,7 +189,7 @@ impl StartCmd {
         Supervisor::new(
             peer_list,
             ProdForkDetector::default(),
-            ProdEvidenceReporter::new(peer_map.clone()),
+            ProdEvidenceReporter::new(peer_map),
         )
     }
 }

light-node/src/rpc.rs

@@ -9,7 +9,7 @@ pub use sealed::{Client, Rpc, Server};
 
 /// Run the given [`Server`] on the given address and blocks until closed.
 ///
-/// n.b. The underlying server has semantics to close on drop. Also does it not offer any way to
+/// n.b. The underlying server has semantics to close on drop. Also does it does not offer any way to
 /// get the underlying Future to await, so we are left with this rather rudimentary way to control
 /// the lifecycle. Should we be interested in a more controlled way to close the server we can
 /// expose a handle in the future.
@@ -38,13 +38,18 @@ mod sealed {
     use jsonrpc_derive::rpc;
 
     use tendermint_light_client::supervisor::Handle;
+    use tendermint_light_client::types::LatestStatus;
     use tendermint_light_client::types::LightBlock;
 
     #[rpc]
     pub trait Rpc {
         /// Returns the latest trusted block.
         #[rpc(name = "state")]
         fn state(&self) -> FutureResult<Option<LightBlock>, Error>;
+
+        /// Returns the latest status.
+        #[rpc(name = "status")]
+        fn status(&self) -> FutureResult<LatestStatus, Error>;
     }
 
     pub use self::rpc_impl_Rpc::gen_client::Client;
@@ -79,6 +84,17 @@ mod sealed {
 
             future::result(res)
         }
+
+        fn status(&self) -> FutureResult<LatestStatus, Error> {
+            let res = self.handle.latest_status().map_err(|e| {
+                let mut err = Error::internal_error();
+                err.message = e.to_string();
+                err.data = serde_json::to_value(e.kind()).ok();
+                err
+            });
+
+            future::result(res)
+        }
     }
 }
 
@@ -92,6 +108,7 @@ mod test {
 
     use tendermint_light_client::errors::Error;
     use tendermint_light_client::supervisor::Handle;
+    use tendermint_light_client::types::LatestStatus;
     use tendermint_light_client::types::LightBlock;
 
     use super::{Client, Rpc as _, Server};
@@ -111,6 +128,21 @@ mod test {
         assert_eq!(have, want);
     }
 
+    #[tokio::test]
+    async fn status() {
+        let server = Server::new(MockHandle {});
+        let fut = {
+            let mut io = IoHandler::new();
+            io.extend_with(server.to_delegate());
+            let (client, server) = local::connect::<Client, _, _>(io);
+            client.status().join(server)
+        };
+        let (have, _) = fut.compat().await.unwrap();
+        let want = serde_json::from_str(STATUS_JSON).unwrap();
+
+        assert_eq!(have, want);
+    }
+
     struct MockHandle;
 
     impl Handle for MockHandle {
@@ -119,6 +151,11 @@ mod test {
 
             Ok(Some(block))
         }
+        fn latest_status(&self) -> Result<LatestStatus, Error> {
+            let status: LatestStatus = serde_json::from_str(STATUS_JSON).unwrap();
+
+            Ok(status)
+        }
     }
 
     const LIGHTBLOCK_JSON: &str = r#"
@@ -239,4 +276,14 @@ mod test {
     "provider": "9D61B19DEFFD5A60BA844AF492EC2CC44449C569"
 }
 "#;
+    const STATUS_JSON: &str = r#"
+{
+    "block_hash": "5A55D7AF2DF9AE4BF4B46FDABBBAD1B66D37B5E044A4843AB0FB0EBEC3E0422C",
+    "connected_nodes": [
+      "BADFADAD0BEFEEDC0C0ADEADBEEFC0FFEEFACADE",
+      "CEFEEDBADFADAD0C0CEEFACADE0ADEADBEEFC0FF"
+    ],
+    "height": 1565,
+    "valset_hash": "74F2AC2B6622504D08DD2509E28CE731985CFE4D133C9DB0CB85763EDCA95AA3"
+}"#;
 }