Stop downloading unnecessary blocks in Zebra acceptance tests (#3072)

* Implement graceful shutdown for the peer set

* Use the minimum lookahead limit in acceptance tests

* Enable a doctest that compiles with newly public modules

zebrad/src/components.rs

@@ -6,10 +6,14 @@
 //! don't fit the async context well.
 
 mod inbound;
+#[allow(missing_docs)]
 pub mod mempool;
 pub mod metrics;
+#[allow(missing_docs)]
 pub mod sync;
+#[allow(missing_docs)]
 pub mod tokio;
+#[allow(missing_docs)]
 pub mod tracing;
 
 pub use inbound::Inbound;

zebrad/src/components/inbound.rs

@@ -1,3 +1,10 @@
+//! The inbound service handles requests from Zebra's peers.
+//!
+//! It downloads and verifies gossiped blocks and mempool transactions,
+//! when Zebra is close to the chain tip.
+//!
+//! It also responds to peer requests for blocks, transactions, and peer addresses.
+
 use std::{
     future::Future,
     pin::Pin,
@@ -128,6 +135,10 @@ pub struct Inbound {
 }
 
 impl Inbound {
+    /// Create a new inbound service.
+    ///
+    /// The address book and peer set use the newly created inbound service.
+    /// So they are sent via the `network_setup` channel after initialization.
     pub fn new(
         network_setup: oneshot::Receiver<NetworkSetupData>,
         state: State,

zebrad/src/components/mempool.rs

@@ -42,7 +42,7 @@ use zebra_state::{ChainTipChange, TipAction};
 
 use crate::components::sync::SyncStatus;
 
-mod config;
+pub mod config;
 mod crawler;
 pub mod downloads;
 mod error;

zebrad/src/components/mempool/crawler.rs

@@ -13,7 +13,7 @@
 //!
 //! # Example
 //!
-//! ```compile_fail
+//! ```
 //! use zebrad::components::mempool;
 //! #
 //! # use zebra_chain::parameters::Network;

zebrad/src/components/sync.rs

@@ -1,3 +1,7 @@
+//! The syncer downloads and verifies large numbers of blocks from peers to Zebra.
+//!
+//! It is used when Zebra is a long way behind the current chain tip.
+
 use std::{collections::HashSet, pin::Pin, sync::Arc, time::Duration};
 
 use color_eyre::eyre::{eyre, Report};
@@ -69,7 +73,12 @@ const BLOCK_DOWNLOAD_RETRY_LIMIT: usize = 2;
 /// Once these malicious blocks start failing validation, the syncer will cancel all
 /// the pending download and verify tasks, drop all the blocks, and start a new
 /// ObtainTips with a new set of peers.
-const MIN_LOOKAHEAD_LIMIT: usize = zebra_consensus::MAX_CHECKPOINT_HEIGHT_GAP * 2;
+pub const MIN_LOOKAHEAD_LIMIT: usize = zebra_consensus::MAX_CHECKPOINT_HEIGHT_GAP * 2;
+
+/// The default for the user-specified lookahead limit.
+///
+/// See [`MIN_LOOKAHEAD_LIMIT`] for details.
+pub const DEFAULT_LOOKAHEAD_LIMIT: usize = zebra_consensus::MAX_CHECKPOINT_HEIGHT_GAP * 5;
 
 /// Controls how long we wait for a tips response to return.
 ///

zebrad/src/components/tracing.rs

@@ -1,3 +1,5 @@
+//! Tracing and logging infrastructure for Zebra.
+
 mod component;
 mod endpoint;
 mod flame;

zebrad/src/config.rs

@@ -8,11 +8,12 @@ use std::{net::SocketAddr, path::PathBuf};
 
 use serde::{Deserialize, Serialize};
 
-use crate::components::mempool::Config as MempoolSection;
 use zebra_consensus::Config as ConsensusSection;
 use zebra_network::Config as NetworkSection;
 use zebra_state::Config as StateSection;
 
+use crate::components::{mempool::Config as MempoolSection, sync};
+
 /// Configuration for `zebrad`.
 ///
 /// The `zebrad` config is a TOML-encoded version of this structure. The meaning
@@ -180,7 +181,7 @@ impl Default for SyncSection {
     fn default() -> Self {
         Self {
             max_concurrent_block_requests: 50,
-            lookahead_limit: 2_000,
+            lookahead_limit: sync::DEFAULT_LOOKAHEAD_LIMIT,
         }
     }
 }

zebrad/src/lib.rs

@@ -36,11 +36,10 @@ extern crate tracing;
 /// parameterized by 'a), *not* that the object itself has 'static lifetime.
 pub type BoxError = Box<dyn std::error::Error + Send + Sync + 'static>;
 
-mod components;
-
 pub mod application;
 pub mod async_ext;
 pub mod commands;
+pub mod components;
 pub mod config;
 pub mod prelude;
 pub mod sentry;

zebrad/tests/acceptance.rs

@@ -46,7 +46,10 @@ use zebra_test::{
     net::random_known_port,
     prelude::*,
 };
-use zebrad::config::ZebradConfig;
+use zebrad::{
+    components::{mempool, sync},
+    config::{SyncSection, ZebradConfig},
+};
 
 /// The amount of time we wait after launching `zebrad`.
 ///
@@ -54,18 +57,41 @@ use zebrad::config::ZebradConfig;
 /// metrics or tracing test failures in Windows CI.
 const LAUNCH_DELAY: Duration = Duration::from_secs(10);
 
+/// Returns a config with:
+/// - a Zcash listener on an unused port on IPv4 localhost, and
+/// - an ephemeral state,
+/// - the minimum syncer lookahead limit, and
+/// - shorter task intervals, to improve test coverage.
 fn default_test_config() -> Result<ZebradConfig> {
-    let auto_port_ipv4_local = zebra_network::Config {
+    const TEST_DURATION: Duration = Duration::from_secs(30);
+
+    let network = zebra_network::Config {
+        // The OS automatically chooses an unused port.
         listen_addr: "127.0.0.1:0".parse()?,
-        crawl_new_peer_interval: Duration::from_secs(30),
+        crawl_new_peer_interval: TEST_DURATION,
         ..zebra_network::Config::default()
     };
-    let local_ephemeral = ZebradConfig {
+
+    let sync = SyncSection {
+        // Avoid downloading unnecessary blocks.
+        lookahead_limit: sync::MIN_LOOKAHEAD_LIMIT,
+        ..SyncSection::default()
+    };
+
+    let mempool = mempool::Config {
+        eviction_memory_time: TEST_DURATION,
+        ..mempool::Config::default()
+    };
+
+    let config = ZebradConfig {
+        network,
         state: zebra_state::Config::ephemeral(),
-        network: auto_port_ipv4_local,
+        sync,
+        mempool,
         ..ZebradConfig::default()
     };
-    Ok(local_ephemeral)
+
+    Ok(config)
 }
 
 fn persistent_test_config() -> Result<ZebradConfig> {
@@ -949,6 +975,7 @@ fn sync_until(
 fn cached_mandatory_checkpoint_test_config() -> Result<ZebradConfig> {
     let mut config = persistent_test_config()?;
     config.state.cache_dir = "/zebrad-cache".into();
+    config.sync.lookahead_limit = sync::DEFAULT_LOOKAHEAD_LIMIT;
     Ok(config)
 }