Port validator_client to stable futures (#1114)

* Add PH & MS slot clock changes

* Account for genesis time

* Add progress on duties refactor

* Add simple is_aggregator bool to val subscription

* Start work on attestation_verification.rs

* Add progress on ObservedAttestations

* Progress with ObservedAttestations

* Fix tests

* Add observed attestations to the beacon chain

* Add attestation observation to processing code

* Add progress on attestation verification

* Add first draft of ObservedAttesters

* Add more tests

* Add observed attesters to beacon chain

* Add observers to attestation processing

* Add more attestation verification

* Create ObservedAggregators map

* Remove commented-out code

* Add observed aggregators into chain

* Add progress

* Finish adding features to attestation verification

* Ensure beacon chain compiles

* Link attn verification into chain

* Integrate new attn verification in chain

* Remove old attestation processing code

* Start trying to fix beacon_chain tests

* Split adding into pools into two functions

* Add aggregation to harness

* Get test harness working again

* Adjust the number of aggregators for test harness

* Fix edge-case in harness

* Integrate new attn processing in network

* Fix compile bug in validator_client

* Update validator API endpoints

* Fix aggreagation in test harness

* Fix enum thing

* Fix attestation observation bug:

* Patch failing API tests

* Start adding comments to attestation verification

* Remove unused attestation field

* Unify "is block known" logic

* Update comments

* Supress fork choice errors for network processing

* Add todos

* Tidy

* Add gossip attn tests

* Disallow test harness to produce old attns

* Comment out in-progress tests

* Partially address pruning tests

* Fix failing store test

* Add aggregate tests

* Add comments about which spec conditions we check

* Dont re-aggregate

* Split apart test harness attn production

* Fix compile error in network

* Make progress on commented-out test

* Fix skipping attestation test

* Add fork choice verification tests

* Tidy attn tests, remove dead code

* Remove some accidentally added code

* Fix clippy lint

* Rename test file

* Add block tests, add cheap block proposer check

* Rename block testing file

* Add observed_block_producers

* Tidy

* Switch around block signature verification

* Finish block testing

* Remove gossip from signature tests

* First pass of self review

* Fix deviation in spec

* Update test spec tags

* Start moving over to hashset

* Finish moving observed attesters to hashmap

* Move aggregation pool over to hashmap

* Make fc attn borrow again

* Fix rest_api compile error

* Fix missing comments

* Fix monster test

* Uncomment increasing slots test

* Address remaining comments

* Remove unsafe, use cfg test

* Remove cfg test flag

* Fix dodgy comment

* Revert "Update hashmap hashset to stable futures"

This reverts commit d432378a3c.

* Revert "Adds panic test to hashset delay"

This reverts commit 281502396f.

* Ported attestation_service

* Ported duties_service

* Ported fork_service

* More ports

* Port block_service

* Minor fixes

* VC compiles

* Update TODOS

* Borrow self where possible

* Ignore aggregates that are already known.

* Unify aggregator modulo logic

* Fix typo in logs

* Refactor validator subscription logic

* Avoid reproducing selection proof

* Skip HTTP call if no subscriptions

* Rename DutyAndState -> DutyAndProof

* Tidy logs

* Print root as dbg

* Fix compile errors in tests

* Fix compile error in test

* Re-Fix attestation and duties service

* Minor fixes

Co-authored-by: Paul Hauner <paul@paulhauner.com>

validator_client/src/fork_service.rs

@@ -1,14 +1,13 @@
 use environment::RuntimeContext;
 use exit_future::Signal;
-use futures::{Future, Stream};
+use futures::{FutureExt, StreamExt};
 use parking_lot::RwLock;
 use remote_beacon_node::RemoteBeaconNode;
-use slog::{crit, info, trace};
+use slog::{info, trace};
 use slot_clock::SlotClock;
 use std::ops::Deref;
 use std::sync::Arc;
-use std::time::{Duration, Instant};
-use tokio::timer::Interval;
+use tokio::time::{interval_at, Duration, Instant};
 use types::{ChainSpec, EthSpec, Fork};
 
 /// Delay this period of time after the slot starts. This allows the node to process the new slot.
@@ -111,51 +110,46 @@ impl<T: SlotClock + 'static, E: EthSpec> ForkService<T, E> {
 
         let interval = {
             let slot_duration = Duration::from_millis(spec.milliseconds_per_slot);
-            Interval::new(
+            // Note: interval_at panics if `slot_duration * E::slots_per_epoch()` = 0
+            interval_at(
                 Instant::now() + duration_to_next_epoch + TIME_DELAY_FROM_SLOT,
                 slot_duration * E::slots_per_epoch() as u32,
             )
         };
 
         let (exit_signal, exit_fut) = exit_future::signal();
-        let service = self.clone();
-        let log_1 = log.clone();
-        let log_2 = log.clone();
 
         // Run an immediate update before starting the updater service.
-        self.context.executor.spawn(service.clone().do_update());
+        let service_1 = self.clone();
+        let service_2 = self.clone();
+        tokio::task::spawn(service_1.do_update());
 
-        self.context.executor.spawn(
-            exit_fut
-                .until(
-                    interval
-                        .map_err(move |e| {
-                            crit! {
-                                log_1,
-                                "Timer thread failed";
-                                "error" => format!("{}", e)
-                            }
-                        })
-                        .for_each(move |_| service.do_update().then(|_| Ok(()))),
-                )
-                .map(move |_| info!(log_2, "Shutdown complete")),
+        let interval_fut = interval.for_each(move |_| {
+            let _ = service_2.clone().do_update();
+            futures::future::ready(())
+        });
+
+        let future = futures::future::select(
+            interval_fut,
+            exit_fut.map(move |_| info!(log, "Shutdown complete")),
         );
+        tokio::task::spawn(future);
 
         Ok(exit_signal)
     }
 
     /// Attempts to download the `Fork` from the server.
-    fn do_update(&self) -> impl Future<Item = (), Error = ()> {
-        let service_1 = self.clone();
-        let log_1 = service_1.context.log.clone();
-        let log_2 = service_1.context.log.clone();
-
-        self.inner
+    async fn do_update(self) -> Result<(), ()> {
+        let log_1 = self.context.log.clone();
+        let log_2 = self.context.log.clone();
+        let _ = self
+            .inner
             .beacon_node
             .http
             .beacon()
             .get_fork()
-            .map(move |fork| *(service_1.fork.write()) = Some(fork))
+            .await
+            .map(move |fork| *(self.fork.write()) = Some(fork))
             .map(move |_| trace!(log_1, "Fork update success"))
             .map_err(move |e| {
                 trace!(
@@ -163,9 +157,9 @@ impl<T: SlotClock + 'static, E: EthSpec> ForkService<T, E> {
                     "Fork update failed";
                     "error" => format!("Error retrieving fork: {:?}", e)
                 )
-            })
-            // Returning an error will stop the interval. This is not desired, a single failure
-            // should not stop all future attempts.
-            .then(|_| Ok(()))
+            });
+        // Returning an error will stop the interval. This is not desired, a single failure
+        // should not stop all future attempts.
+        Ok(())
     }
 }