Reply to `Request::MempoolTransactionIds` with mempool content (#2720)

* reply to `Request::MempoolTransactionIds`

* remove boilerplate

* get storage from mempool with a method

* change panic message

* try fix for mac

* use normal init instead of init_tests for state service

* newline

* rustfmt

* fix test build

zebrad/src/commands/start.rs

@@ -64,6 +64,9 @@ impl StartCmd {
         )
         .await;
 
+        info!("initializing mempool");
+        let mempool = mempool::Mempool::new(config.network.network);
+
         info!("initializing network");
         // The service that our node uses to respond to requests by peers. The
         // load_shed middleware ensures that we reduce the size of the peer set
@@ -77,6 +80,7 @@ impl StartCmd {
                 state.clone(),
                 chain_verifier.clone(),
                 tx_verifier.clone(),
+                mempool,
             ));
 
         let (peer_set, address_book) =

zebrad/src/components/inbound.rs

@@ -25,9 +25,15 @@ use super::mempool::downloads::{
     Downloads as TxDownloads, TRANSACTION_DOWNLOAD_TIMEOUT, TRANSACTION_VERIFY_TIMEOUT,
 };
 // Re-use the syncer timeouts for consistency.
-use super::sync::{BLOCK_DOWNLOAD_TIMEOUT, BLOCK_VERIFY_TIMEOUT};
+use super::{
+    mempool,
+    sync::{BLOCK_DOWNLOAD_TIMEOUT, BLOCK_VERIFY_TIMEOUT},
+};
 
 mod downloads;
+#[cfg(test)]
+mod tests;
+
 use downloads::Downloads as BlockDownloads;
 
 type Outbound = Buffer<BoxService<zn::Request, zn::Response, zn::BoxError>, zn::Request>;
@@ -126,6 +132,9 @@ pub struct Inbound {
 
     /// A service that manages cached blockchain state.
     state: State,
+
+    /// A service that manages transactions in the memory pool.
+    mempool: mempool::Mempool,
 }
 
 impl Inbound {
@@ -134,6 +143,7 @@ impl Inbound {
         state: State,
         block_verifier: BlockVerifier,
         tx_verifier: TxVerifier,
+        mempool: mempool::Mempool,
     ) -> Self {
         Self {
             network_setup: Setup::AwaitingNetwork {
@@ -142,6 +152,7 @@ impl Inbound {
                 tx_verifier,
             },
             state,
+            mempool,
         }
     }
 
@@ -372,8 +383,11 @@ impl Service<zn::Request> for Inbound {
                 async { Ok(zn::Response::Nil) }.boxed()
             }
             zn::Request::MempoolTransactionIds => {
-                debug!("ignoring unimplemented request");
+                self.mempool.clone().oneshot(mempool::Request::TransactionIds).map_ok(|resp| match resp {
-                async { Ok(zn::Response::Nil) }.boxed()
+                    mempool::Response::TransactionIds(transaction_ids) => zn::Response::TransactionIds(transaction_ids),
+                    _ => unreachable!("Mempool component should always respond to a `TransactionIds` request with a `TransactionIds` response"),
+                })
+                .boxed()
             }
             zn::Request::Ping(_) => {
                 unreachable!("ping requests are handled internally");

zebrad/src/components/inbound/tests.rs

@@ -0,0 +1,69 @@
+use tower::ServiceExt;
+
+use super::mempool::{unmined_transactions_in_blocks, Mempool};
+
+use tokio::sync::oneshot;
+use tower::builder::ServiceBuilder;
+
+use zebra_chain::{
+    parameters::Network,
+    transaction::{UnminedTx, UnminedTxId},
+};
+use zebra_consensus::Config as ConsensusConfig;
+use zebra_network::{Request, Response};
+use zebra_state::Config as StateConfig;
+
+#[tokio::test]
+async fn mempool_requests_for_transaction_ids() {
+    let network = Network::Mainnet;
+    let consensus_config = ConsensusConfig::default();
+    let state_config = StateConfig::ephemeral();
+
+    let (state, _, _) = zebra_state::init(state_config, network);
+    let state_service = ServiceBuilder::new().buffer(1).service(state);
+    let mut mempool_service = Mempool::new(network);
+
+    let added_transaction_ids: Vec<UnminedTxId> =
+        add_some_stuff_to_mempool(&mut mempool_service, network)
+            .iter()
+            .map(|t| t.id)
+            .collect();
+
+    let (block_verifier, transaction_verifier) =
+        zebra_consensus::chain::init(consensus_config.clone(), network, state_service.clone())
+            .await;
+    let (_setup_tx, setup_rx) = oneshot::channel();
+
+    let inbound_service = ServiceBuilder::new()
+        .load_shed()
+        .buffer(1)
+        .service(super::Inbound::new(
+            setup_rx,
+            state_service,
+            block_verifier.clone(),
+            transaction_verifier.clone(),
+            mempool_service,
+        ));
+
+    let request = inbound_service
+        .oneshot(Request::MempoolTransactionIds)
+        .await;
+    match request {
+        Ok(Response::TransactionIds(response)) => assert_eq!(response, added_transaction_ids),
+        _ => unreachable!(
+            "`MempoolTransactionIds` requests should always respond `Ok(Vec<UnminedTxId>)`"
+        ),
+    };
+}
+
+fn add_some_stuff_to_mempool(mempool_service: &mut Mempool, network: Network) -> Vec<UnminedTx> {
+    // get the genesis block transactions from the Zcash blockchain.
+    let genesis_transactions = unmined_transactions_in_blocks(0, network);
+    // Insert the genesis block coinbase transaction into the mempool storage.
+    mempool_service
+        .storage()
+        .insert(genesis_transactions.1[0].clone())
+        .unwrap();
+
+    genesis_transactions.1
+}

zebrad/src/components/mempool.rs

@@ -27,6 +27,8 @@ mod tests;
 
 pub use self::crawler::Crawler;
 pub use self::error::MempoolError;
+#[cfg(test)]
+pub use self::storage::tests::unmined_transactions_in_blocks;
 
 #[derive(Debug)]
 #[allow(dead_code)]
@@ -62,6 +64,12 @@ impl Mempool {
             storage: Default::default(),
         }
     }
+
+    ///  Get the storage field of the mempool for testing purposes.
+    #[cfg(test)]
+    pub fn storage(&mut self) -> &mut storage::Storage {
+        &mut self.storage
+    }
 }
 
 impl Service<Request> for Mempool {