feat(grpc): Add initial `Getinfo` grpc (#8178)

* add `zebra-grpc` crate

* add missing fields

* convert to a lib

* add zebra-scan and tonic as depenency

* add a getinfo grpc

* remove zebra-scanner dependency

* Adds scan_service field to scanner grpc server

* remove dependency

* test launching the grpc server from the zebra-scan crate (not building)

* fix async issue

* fixes build issues

* add binary for manual testing

* try fix try run

---------

Co-authored-by: Arya <aryasolhi@gmail.com>

.github/workflows/scripts/release-crates-dry-run.sh

@@ -18,7 +18,8 @@ fi
 
 # Release process
 # Ensure to have an extra `--no-confirm` argument for non-interactive testing.
-cargo release version --verbose --execute --no-confirm --allow-branch '*' --workspace --exclude zebrad beta
+cargo release version --verbose --execute --no-confirm --allow-branch '*' --workspace --exclude zebrad --exclude zebra-scan --exclude zebra-grpc beta
+# TODO: `zebra-scan` and `zebra-grpc` has to be updated with exact versions, we are skipping them by now.
 cargo release version --verbose --execute --no-confirm --allow-branch '*' --package zebrad patch
 cargo release replace --verbose --execute --no-confirm --allow-branch '*' --package zebrad
 cargo release commit --verbose --execute --no-confirm --allow-branch '*'

Cargo.lock

@@ -5766,8 +5766,15 @@ dependencies = [
 name = "zebra-grpc"
 version = "0.1.0-alpha.1"
 dependencies = [
+ "color-eyre",
+ "futures-util",
+ "prost",
+ "tokio",
  "tonic",
- "zebra-scan",
+ "tonic-build",
+ "tower",
+ "zcash_primitives",
+ "zebra-node-services",
 ]
 
 [[package]]
@@ -5880,6 +5887,7 @@ dependencies = [
  "zcash_note_encryption",
  "zcash_primitives",
  "zebra-chain",
+ "zebra-grpc",
  "zebra-node-services",
  "zebra-state",
  "zebra-test",

zebra-grpc/Cargo.toml

@@ -16,6 +16,16 @@ categories = ["cryptography::cryptocurrencies"]
 
 [dependencies]
 
+futures-util = "0.3.28"
 tonic = "0.10.2"
+prost = "0.12.3"
+tokio = { version = "1.35.1", features = ["macros", "rt-multi-thread"] }
+tower = { version = "0.4.13", features = ["util", "buffer"] }
+color-eyre = "0.6.2"
 
-zebra-scan = { path = "../zebra-scan", version = "0.1.0-alpha.1" }
+zcash_primitives = { version = "0.13.0-rc.1" }
+
+zebra-node-services = { path = "../zebra-node-services", version = "1.0.0-beta.34" }
+
+[build-dependencies]
+tonic-build = "0.10.2"

zebra-grpc/build.rs

@@ -0,0 +1,6 @@
+//! Compile proto files
+
+fn main() -> Result<(), Box<dyn std::error::Error>> {
+    tonic_build::compile_protos("proto/scanner.proto")?;
+    Ok(())
+}

zebra-grpc/proto/scanner.proto

@@ -0,0 +1,16 @@
+syntax = "proto3";
+package scanner;
+
+// Empty is for gRPCs that take no arguments, currently only GetInfo.
+message Empty {}
+
+service Scanner {
+    // Get information about the scanner service.
+    rpc GetInfo (Empty) returns (InfoReply);
+}
+
+// A response to a GetInfo call.
+message InfoReply {
+    // The minimum sapling height allowed.
+    uint32 min_sapling_birthday_height = 1;
+}

zebra-grpc/src/lib.rs

@@ -3,3 +3,5 @@
 #![doc(html_favicon_url = "https://zfnd.org/wp-content/uploads/2022/03/zebra-favicon-128.png")]
 #![doc(html_logo_url = "https://zfnd.org/wp-content/uploads/2022/03/zebra-icon.png")]
 #![doc(html_root_url = "https://docs.rs/zebra_grpc")]
+
+pub mod server;

zebra-grpc/src/server.rs

@@ -0,0 +1,91 @@
+//! The gRPC server implementation
+
+use futures_util::future::TryFutureExt;
+use tonic::{transport::Server, Response, Status};
+use tower::ServiceExt;
+
+use scanner::scanner_server::{Scanner, ScannerServer};
+use scanner::{Empty, InfoReply};
+
+use zebra_node_services::scan_service::{
+    request::Request as ScanServiceRequest, response::Response as ScanServiceResponse,
+};
+
+/// The generated scanner proto
+pub mod scanner {
+    tonic::include_proto!("scanner");
+}
+
+type BoxError = Box<dyn std::error::Error + Send + Sync + 'static>;
+
+#[derive(Debug)]
+/// The server implementation
+pub struct ScannerRPC<ScanService>
+where
+    ScanService: tower::Service<ScanServiceRequest, Response = ScanServiceResponse, Error = BoxError>
+        + Clone
+        + Send
+        + Sync
+        + 'static,
+    <ScanService as tower::Service<ScanServiceRequest>>::Future: Send,
+{
+    scan_service: ScanService,
+}
+
+#[tonic::async_trait]
+impl<ScanService> Scanner for ScannerRPC<ScanService>
+where
+    ScanService: tower::Service<ScanServiceRequest, Response = ScanServiceResponse, Error = BoxError>
+        + Clone
+        + Send
+        + Sync
+        + 'static,
+    <ScanService as tower::Service<ScanServiceRequest>>::Future: Send,
+{
+    async fn get_info(
+        &self,
+        _request: tonic::Request<Empty>,
+    ) -> Result<Response<InfoReply>, Status> {
+        let ScanServiceResponse::Info {
+            min_sapling_birthday_height,
+        } = self
+            .scan_service
+            .clone()
+            .ready()
+            .and_then(|service| service.call(ScanServiceRequest::Info))
+            .await
+            .map_err(|_| Status::unknown("scan service was unavailable"))?
+        else {
+            return Err(Status::unknown(
+                "scan service returned an unexpected response",
+            ));
+        };
+
+        let reply = scanner::InfoReply {
+            min_sapling_birthday_height: min_sapling_birthday_height.0,
+        };
+
+        Ok(Response::new(reply))
+    }
+}
+
+/// Initializes the zebra-scan gRPC server
+pub async fn init<ScanService>(scan_service: ScanService) -> Result<(), color_eyre::Report>
+where
+    ScanService: tower::Service<ScanServiceRequest, Response = ScanServiceResponse, Error = BoxError>
+        + Clone
+        + Send
+        + Sync
+        + 'static,
+    <ScanService as tower::Service<ScanServiceRequest>>::Future: Send,
+{
+    let addr = "[::1]:50051".parse()?;
+    let service = ScannerRPC { scan_service };
+
+    Server::builder()
+        .add_service(ScannerServer::new(service))
+        .serve(addr)
+        .await?;
+
+    Ok(())
+}

zebra-node-services/src/scan_service/request.rs

@@ -3,6 +3,9 @@
 #[derive(Debug)]
 /// Request types for `zebra_scan::service::ScanService`
 pub enum Request {
+    /// Requests general info about the scanner
+    Info,
+
     /// TODO: Accept `KeyHash`es and return key hashes that are registered
     CheckKeyHashes(Vec<()>),
 

zebra-node-services/src/scan_service/response.rs

@@ -2,11 +2,17 @@
 
 use std::sync::{mpsc, Arc};
 
-use zebra_chain::transaction::Transaction;
+use zebra_chain::{block::Height, transaction::Transaction};
 
 #[derive(Debug)]
 /// Response types for `zebra_scan::service::ScanService`
 pub enum Response {
+    /// Response to the `Info` request
+    Info {
+        /// The minimum sapling birthday height for the shielded scanner
+        min_sapling_birthday_height: Height,
+    },
+
     /// Response to Results request
     Results(Vec<Transaction>),
 

zebra-scan/Cargo.toml

@@ -14,6 +14,10 @@ keywords = ["zebra", "zcash"]
 # Must be one of <https://crates.io/category_slugs>
 categories = ["cryptography::cryptocurrencies"]
 
+[[bin]] # Bin to run the Scanner gRPC server
+name = "scanner-grpc-server"
+path = "src/bin/rpc_server.rs"
+
 [features]
 
 # Production features that activate extra dependencies, or extra features in dependencies
@@ -52,6 +56,7 @@ zcash_primitives = "0.13.0-rc.1"
 zebra-chain = { path = "../zebra-chain", version = "1.0.0-beta.34" }
 zebra-state = { path = "../zebra-state", version = "1.0.0-beta.34", features = ["shielded-scan"] }
 zebra-node-services = { path = "../zebra-node-services", version = "1.0.0-beta.33" }
+zebra-grpc = { path = "../zebra-grpc", version = "0.1.0-alpha.1" }
 
 chrono = { version = "0.4.32", default-features = false, features = ["clock", "std", "serde"] }
 

zebra-scan/src/bin/rpc_server.rs

@@ -0,0 +1,19 @@
+//! Runs an RPC server with a mock ScanTask
+
+use tower::ServiceBuilder;
+
+use zebra_scan::service::ScanService;
+
+#[tokio::main]
+/// Runs an RPC server with a mock ScanTask
+async fn main() -> Result<(), Box<dyn std::error::Error>> {
+    let (config, network) = Default::default();
+    let scan_service = ServiceBuilder::new()
+        .buffer(10)
+        .service(ScanService::new_with_mock_scanner(&config, network));
+
+    // Start the gRPC server.
+    zebra_grpc::server::init(scan_service).await?;
+
+    Ok(())
+}

zebra-scan/src/init.rs

@@ -4,12 +4,12 @@ use std::sync::{mpsc, Arc};
 
 use color_eyre::Report;
 use tokio::{sync::oneshot, task::JoinHandle};
-use tracing::Instrument;
+use tower::ServiceBuilder;
 
-use zebra_chain::{diagnostic::task::WaitForPanics, parameters::Network, transaction::Transaction};
+use zebra_chain::{parameters::Network, transaction::Transaction};
 use zebra_state::ChainTipChange;
 
-use crate::{scan, storage::Storage, Config};
+use crate::{scan, service::ScanService, Config};
 
 #[derive(Debug)]
 /// Commands that can be sent to [`ScanTask`]
@@ -47,6 +47,16 @@ pub struct ScanTask {
 }
 
 impl ScanTask {
+    /// Spawns a new [`ScanTask`] for tests.
+    pub fn mock() -> Self {
+        let (cmd_sender, _cmd_receiver) = mpsc::channel();
+
+        Self {
+            handle: tokio::spawn(std::future::pending()),
+            cmd_sender,
+        }
+    }
+
     /// Spawns a new [`ScanTask`].
     pub fn spawn(
         config: &Config,
@@ -58,7 +68,7 @@ impl ScanTask {
         let (cmd_sender, _cmd_receiver) = mpsc::channel();
 
         Self {
-            handle: spawn_init(config, network, state, chain_tip_change),
+            handle: scan::spawn_init(config, network, state, chain_tip_change),
             cmd_sender,
         }
     }
@@ -81,13 +91,10 @@ pub fn spawn_init(
     state: scan::State,
     chain_tip_change: ChainTipChange,
 ) -> JoinHandle<Result<(), Report>> {
-    let config = config.clone();
-
-    // TODO: spawn an entirely new executor here, to avoid timing attacks.
-    tokio::spawn(init(config, network, state, chain_tip_change).in_current_span())
+    scan::spawn_init(config, network, state, chain_tip_change)
 }
 
-/// Initialize the scanner based on its config.
+/// Initialize [`ScanService`] based on its config.
 ///
 /// TODO: add a test for this function.
 pub async fn init(
@@ -96,10 +103,15 @@ pub async fn init(
     state: scan::State,
     chain_tip_change: ChainTipChange,
 ) -> Result<(), Report> {
-    let storage = tokio::task::spawn_blocking(move || Storage::new(&config, network, false))
-        .wait_for_panics()
-        .await;
+    let scan_service = ServiceBuilder::new().buffer(10).service(ScanService::new(
+        &config,
+        network,
+        state,
+        chain_tip_change,
+    ));
 
-    // TODO: add more tasks here?
-    scan::start(state, chain_tip_change, storage).await
+    // Start the gRPC server.
+    zebra_grpc::server::init(scan_service).await?;
+
+    Ok(())
 }

zebra-scan/src/lib.rs

@@ -14,7 +14,7 @@ pub mod storage;
 
 use zebra_node_services::scan_service::{request::Request, response::Response};
 
-mod service;
+pub mod service;
 #[cfg(any(test, feature = "proptest-impl"))]
 pub mod tests;
 

zebra-scan/src/scan.rs

@@ -8,8 +8,10 @@ use std::{
 
 use color_eyre::{eyre::eyre, Report};
 use itertools::Itertools;
+use tokio::task::JoinHandle;
 use tower::{buffer::Buffer, util::BoxService, Service, ServiceExt};
 
+use tracing::Instrument;
 use zcash_client_backend::{
     data_api::ScannedBlock,
     encoding::decode_extended_full_viewing_key,
@@ -34,7 +36,10 @@ use zebra_chain::{
 };
 use zebra_state::{ChainTipChange, SaplingScannedResult, TransactionIndex};
 
-use crate::storage::{SaplingScanningKey, Storage};
+use crate::{
+    storage::{SaplingScanningKey, Storage},
+    Config,
+};
 
 /// The generic state type used by the scanner.
 pub type State = Buffer<
@@ -430,3 +435,35 @@ async fn tip_height(mut state: State) -> Result<Height, Report> {
         _ => unreachable!("unmatched response to a state::Tip request"),
     }
 }
+
+/// Initialize the scanner based on its config, and spawn a task for it.
+///
+/// TODO: add a test for this function.
+pub fn spawn_init(
+    config: &Config,
+    network: Network,
+    state: State,
+    chain_tip_change: ChainTipChange,
+) -> JoinHandle<Result<(), Report>> {
+    let config = config.clone();
+
+    // TODO: spawn an entirely new executor here, to avoid timing attacks.
+    tokio::spawn(init(config, network, state, chain_tip_change).in_current_span())
+}
+
+/// Initialize the scanner based on its config.
+///
+/// TODO: add a test for this function.
+pub async fn init(
+    config: Config,
+    network: Network,
+    state: State,
+    chain_tip_change: ChainTipChange,
+) -> Result<(), Report> {
+    let storage = tokio::task::spawn_blocking(move || Storage::new(&config, network, false))
+        .wait_for_panics()
+        .await;
+
+    // TODO: add more tasks here?
+    start(state, chain_tip_change, storage).await
+}

zebra-scan/src/service.rs

@@ -22,7 +22,7 @@ pub struct ScanService {
 
 impl ScanService {
     /// Create a new [`ScanService`].
-    pub fn _new(
+    pub fn new(
         config: &Config,
         network: Network,
         state: scan::State,
@@ -33,6 +33,14 @@ impl ScanService {
             scan_task: ScanTask::spawn(config, network, state, chain_tip_change),
         }
     }
+
+    /// Create a new [`ScanService`] with a mock `ScanTask`
+    pub fn new_with_mock_scanner(config: &Config, network: Network) -> Self {
+        Self {
+            db: Storage::new(config, network, false),
+            scan_task: ScanTask::mock(),
+        }
+    }
 }
 
 impl Service<Request> for ScanService {
@@ -55,6 +63,17 @@ impl Service<Request> for ScanService {
 
     fn call(&mut self, req: Request) -> Self::Future {
         match req {
+            Request::Info => {
+                let db = self.db.clone();
+
+                return async move {
+                    Ok(Response::Info {
+                        min_sapling_birthday_height: db.min_sapling_birthday_height(),
+                    })
+                }
+                .boxed();
+            }
+
             Request::CheckKeyHashes(_key_hashes) => {
                 // TODO: check that these entries exist in db
             }