Improve tokio task execution (#1181)

* Add logging on shutdown

* Replace tokio::spawn with handle.spawn

* Upgrade tokio

* Add a task executor

* Beacon chain tasks use task executor

* Validator client tasks use task executor

* Rename runtime_handle to executor

* Add duration histograms; minor fixes

* Cleanup

* Fix logs

* Fix tests

* Remove random file

* Get enr dependency instead of libp2p

* Address some review comments

* Libp2p takes a TaskExecutor

* Ugly fix libp2p tests

* Move TaskExecutor to own file

* Upgrade Dockerfile rust version

* Minor fixes

* Revert "Ugly fix libp2p tests"

This reverts commit 58d4bb690f.

* Pretty fix libp2p tests

* Add spawn_without_exit; change Counter to Gauge

* Tidy

* Move log from RuntimeContext to TaskExecutor

* Fix errors

* Replace histogram with int_gauge for async tasks

* Fix todo

* Fix memory leak in test by exiting all spawned tasks at the end

beacon_node/eth2-libp2p/src/service.rs

@@ -84,6 +84,7 @@ pub struct Service<TSpec: EthSpec> {
 
 impl<TSpec: EthSpec> Service<TSpec> {
     pub fn new(
+        executor: environment::TaskExecutor,
         config: &NetworkConfig,
         enr_fork_id: EnrForkId,
         log: &slog::Logger,
@@ -122,15 +123,15 @@ impl<TSpec: EthSpec> Service<TSpec> {
             let behaviour = Behaviour::new(&local_keypair, config, network_globals.clone(), &log)?;
 
             // use the executor for libp2p
-            struct Executor(tokio::runtime::Handle);
+            struct Executor(environment::TaskExecutor);
             impl libp2p::core::Executor for Executor {
                 fn exec(&self, f: Pin<Box<dyn Future<Output = ()> + Send>>) {
-                    self.0.spawn(f);
+                    self.0.spawn(f, "libp2p");
                 }
             }
             SwarmBuilder::new(transport, behaviour, local_peer_id.clone())
                 .peer_connection_limit(MAX_CONNECTIONS_PER_PEER)
-                .executor(Box::new(Executor(tokio::runtime::Handle::current())))
+                .executor(Box::new(Executor(executor)))
                 .build()
         };