fix(net): Clean up licensing, closure move, log typos, tracing spans (

#6995)

* Remove a redundant outbound connector timeout

* Fix panics in inbound connection handshaker

* Refactor to simplify FuturesUnordered types

* Make licensing notes consistent

* Delete redundant `move` in closures

* Fix a log typo

* Add some missing tracing spans

zebra-network/Cargo.toml

@@ -7,7 +7,11 @@ description = "Networking code for Zebra"
 #
 # This licence is deliberately different to the rest of Zebra.
 #
-# zebra-network/src/peer_set/set.rs was modified from a 2019 version of:
+# Some code in:
+# zebra-network/src/peer_set/set.rs
+# zebra-network/src/peer_set/unready_service.rs
+# zebra-network/src/peer_set/initialize.rs
+# was modified from a 2019 version of:
 # https://github.com/tower-rs/tower/tree/master/tower/src/balance/p2c/service.rs
 license = "MIT"
 repository = "https://github.com/ZcashFoundation/zebra"

zebra-network/src/config.rs

@@ -13,6 +13,7 @@ use indexmap::IndexSet;
 use serde::{de, Deserialize, Deserializer};
 use tempfile::NamedTempFile;
 use tokio::{fs, io::AsyncWriteExt};
+use tracing::Span;
 
 use zebra_chain::parameters::Network;
 
@@ -493,12 +494,15 @@ impl Config {
 
         // Create the temporary file.
         // Do blocking filesystem operations on a dedicated thread.
+        let span = Span::current();
         let tmp_peer_cache_file = tokio::task::spawn_blocking(move || {
-            // Put the temporary file in the same directory as the permanent file,
-            // so atomic filesystem operations are possible.
-            tempfile::Builder::new()
-                .prefix(&tmp_peer_cache_prefix)
-                .tempfile_in(peer_cache_dir)
+            span.in_scope(move || {
+                // Put the temporary file in the same directory as the permanent file,
+                // so atomic filesystem operations are possible.
+                tempfile::Builder::new()
+                    .prefix(&tmp_peer_cache_prefix)
+                    .tempfile_in(peer_cache_dir)
+            })
         })
         .await
         .expect("unexpected panic creating temporary peer cache file")?;
@@ -514,31 +518,34 @@ impl Config {
 
         // Atomically replace the current cache with the temporary cache.
         // Do blocking filesystem operations on a dedicated thread.
+        let span = Span::current();
         tokio::task::spawn_blocking(move || {
-            let result = tmp_peer_cache_file.persist(&peer_cache_file);
+            span.in_scope(move || {
+                let result = tmp_peer_cache_file.persist(&peer_cache_file);
 
-            // Drops the temp file if needed
-            match result {
-                Ok(_temp_file) => {
-                    info!(
-                        cached_ip_count = ?peer_list.len(),
-                        ?peer_cache_file,
-                        "updated cached peer IP addresses"
-                    );
-
-                    for ip in &peer_list {
-                        metrics::counter!(
-                            "zcash.net.peers.cache",
-                            1,
-                            "cache" => peer_cache_file.display().to_string(),
-                            "remote_ip" => ip.to_string()
+                // Drops the temp file if needed
+                match result {
+                    Ok(_temp_file) => {
+                        info!(
+                            cached_ip_count = ?peer_list.len(),
+                            ?peer_cache_file,
+                            "updated cached peer IP addresses"
                         );
-                    }
 
-                    Ok(())
+                        for ip in &peer_list {
+                            metrics::counter!(
+                                "zcash.net.peers.cache",
+                                1,
+                                "cache" => peer_cache_file.display().to_string(),
+                                "remote_ip" => ip.to_string()
+                            );
+                        }
+
+                        Ok(())
+                    }
+                    Err(error) => Err(error.error),
                 }
-                Err(error) => Err(error.error),
-            }
+            })
         })
         .await
         .expect("unexpected panic making temporary peer cache file permanent")

zebra-network/src/peer_cache_updater.rs

@@ -15,6 +15,7 @@ use crate::{
 };
 
 /// An ongoing task that regularly caches the current `address_book` to disk, based on `config`.
+#[instrument(skip(config, address_book))]
 pub async fn peer_cache_updater(
     config: Config,
     address_book: Arc<Mutex<AddressBook>>,

zebra-network/src/peer_set/initialize.rs

@@ -1,7 +1,8 @@
 //! A peer set whose size is dynamically determined by resource constraints.
-
-// Portions of this submodule were adapted from tower-balance,
-// which is (c) 2019 Tower Contributors (MIT licensed).
+//!
+//! The [`PeerSet`] implementation is adapted from the one in [tower::Balance][tower-balance].
+//!
+//! [tower-balance]: https://github.com/tower-rs/tower/tree/master/tower/src/balance
 
 use std::{
     collections::{BTreeMap, HashSet},
@@ -614,7 +615,7 @@ where
                 peerset_tx.clone(),
             )
             .await?
-            .map(move |res| match res {
+            .map(|res| match res {
                 Ok(()) => (),
                 Err(e @ JoinError { .. }) => {
                     if e.is_panic() {
@@ -632,12 +633,12 @@ where
                 HANDSHAKE_TIMEOUT + Duration::from_millis(500),
                 handshake_task,
             )
-            .map(move |res| match res {
+            .map(|res| match res {
                 Ok(()) => (),
                 Err(_e @ Elapsed { .. }) => {
                     info!(
                         "timeout in spawned accept_inbound_handshake() task: \
-                         inner task should have timeout out already"
+                         inner task should have timed out already"
                     );
                 }
             });
@@ -677,6 +678,9 @@ where
 ///
 /// Uses `handshaker` to perform a Zcash network protocol handshake, and sends
 /// the [`peer::Client`] result over `peerset_tx`.
+//
+// TODO: when we support inbound proxies, distinguish between proxied listeners and
+//       direct listeners in the span generated by this instrument macro
 #[instrument(skip(handshaker, tcp_stream, connection_tracker, peerset_tx))]
 async fn accept_inbound_handshake<S>(
     addr: PeerSocketAddr,
@@ -701,8 +705,6 @@ where
     //
     // This await is okay because the handshaker's `poll_ready` method always returns Ready.
     handshaker.ready().await?;
-    // TODO: distinguish between proxied listeners and direct listeners
-    let handshaker_span = info_span!("listen_handshaker", peer = ?connected_addr);
 
     // Construct a handshake future but do not drive it yet....
     let handshake = handshaker.call(HandshakeRequest {
@@ -724,7 +726,7 @@ where
                 debug!(?handshake_result, "error handshaking with inbound peer");
             }
         }
-        .instrument(handshaker_span),
+        .in_current_span(),
     );
 
     Ok(handshake_task)
@@ -924,8 +926,8 @@ where
 
                         Ok(DemandCrawlFinished)
                     }
-                })
-                .map(move |res| match res {
+                }.in_current_span())
+                .map(|res| match res {
                     Ok(crawler_action) => crawler_action,
                     Err(e @ JoinError {..}) => {
                         if e.is_panic() {
@@ -936,8 +938,7 @@ where
                         // Just fake it
                         Ok(HandshakeFinished)
                     }
-                })
-                .in_current_span();
+                });
 
                 handshakes.push(Box::pin(handshake_or_crawl_handle));
             }
@@ -954,7 +955,7 @@ where
                     crawl(candidates, demand_tx).await?;
 
                     Ok(TimerCrawlFinished)
-                })
+                }.in_current_span())
                 .map(move |res| match res {
                     Ok(crawler_action) => crawler_action,
                     Err(e @ JoinError {..}) => {
@@ -966,8 +967,7 @@ where
                         // Just fake it
                         Ok(TimerCrawlFinished)
                     }
-                })
-                .in_current_span();
+                });
 
                 handshakes.push(Box::pin(crawl_handle));
             }

zebra-network/src/peer_set/set.rs

@@ -3,6 +3,7 @@
 //! # Implementation
 //!
 //! The [`PeerSet`] implementation is adapted from the one in [tower::Balance][tower-balance].
+//!
 //! As described in Tower's documentation, it:
 //!
 //! > Distributes requests across inner services using the [Power of Two Choices][p2c].

zebra-network/src/peer_set/unready_service.rs

@@ -1,6 +1,9 @@
-/// Services that are busy or newly created.
-///
-/// Adapted from tower-balance.
+//! Services that are busy or newly created.
+//!
+//! The [`UnreadyService`] implementation is adapted from the one in [tower::Balance][tower-balance].
+//!
+//! [tower-balance]: https://github.com/tower-rs/tower/tree/master/tower/src/balance
+
 use std::{
     future::Future,
     marker::PhantomData,