Ctrl+C now stops the BN when waiting for genesis (#1761)

* Ctrl+C now stops the BN when waiting for genesis

* proper shutdown when waiting for genesis if Ctrl+C is used

beacon_chain/beacon_node.nim

@@ -26,7 +26,7 @@ import
   spec/state_transition,
   conf, time, beacon_chain_db, validator_pool, extras,
   attestation_pool, exit_pool, eth2_network, eth2_discovery,
-  beacon_node_common, beacon_node_types,
+  beacon_node_common, beacon_node_types, beacon_node_status,
   block_pools/[spec_cache, chain_dag, quarantine, clearance, block_pools_types],
   nimbus_binary_common, network_metadata,
   mainchain_monitor, version, ssz/[merkleization], merkle_minimal,
@@ -42,13 +42,6 @@ const
 type
   RpcServer* = RpcHttpServer
 
-  # "state" is already taken by BeaconState
-  BeaconNodeStatus* = enum
-    Starting, Running, Stopping
-
-# this needs to be global, so it can be set in the Ctrl+C signal handler
-var status = BeaconNodeStatus.Starting
-
 template init(T: type RpcHttpServer, ip: ValidIpAddress, port: Port): T =
   newRpcHttpServer([initTAddress(ip, port)])
 
@@ -190,6 +183,8 @@ proc init*(T: type BeaconNode,
       mainchainMonitor.start()
 
       genesisState = await mainchainMonitor.waitGenesis()
+      if bnStatus == BeaconNodeStatus.Stopping:
+        return nil
 
       info "Eth2 genesis state detected",
         genesisTime = genesisState.genesisTime,
@@ -849,7 +844,7 @@ proc installMessageValidators(node: BeaconNode) =
       node.processor[].voluntaryExitValidator(signedVoluntaryExit))
 
 proc stop*(node: BeaconNode) =
-  status = BeaconNodeStatus.Stopping
+  bnStatus = BeaconNodeStatus.Stopping
   info "Graceful shutdown"
   if not node.config.inProcessValidators:
     node.vcProcess.close()
@@ -858,9 +853,9 @@ proc stop*(node: BeaconNode) =
   info "Database closed"
 
 proc run*(node: BeaconNode) =
-  if status == BeaconNodeStatus.Starting:
+  if bnStatus == BeaconNodeStatus.Starting:
     # it might have been set to "Stopping" with Ctrl+C
-    status = BeaconNodeStatus.Running
+    bnStatus = BeaconNodeStatus.Running
 
     if node.rpcServer != nil:
       node.rpcServer.installRpcHandlers(node)
@@ -888,7 +883,7 @@ proc run*(node: BeaconNode) =
     node.startSyncManager()
 
   # main event loop
-  while status == BeaconNodeStatus.Running:
+  while bnStatus == BeaconNodeStatus.Running:
     try:
       poll()
     except CatchableError as e:
@@ -1208,7 +1203,7 @@ programMain:
         # workaround for https://github.com/nim-lang/Nim/issues/4057
         setupForeignThreadGc()
       info "Shutting down after having received SIGINT"
-      status = BeaconNodeStatus.Stopping
+      bnStatus = BeaconNodeStatus.Stopping
     setControlCHook(controlCHandler)
 
     when useInsecureFeatures:
@@ -1219,6 +1214,8 @@ programMain:
         metrics.startHttpServer($metricsAddress, config.metricsPort)
 
     var node = waitFor BeaconNode.init(rng, config, stateSnapshotContents)
+    if bnStatus == BeaconNodeStatus.Stopping:
+      return
 
     when hasPrompt:
       initPrompt(node)

beacon_chain/beacon_node_status.nim

@@ -0,0 +1,16 @@
+# beacon_chain
+# Copyright (c) 2018-2020 Status Research & Development GmbH
+# Licensed and distributed under either of
+#   * MIT license (license terms in the root directory or at https://opensource.org/licenses/MIT).
+#   * Apache v2 license (license terms in the root directory or at https://www.apache.org/licenses/LICENSE-2.0).
+# at your option. This file may not be copied, modified, or distributed except according to those terms.
+
+type
+  # "state" is already taken by BeaconState
+  BeaconNodeStatus* = enum
+    Starting
+    Running
+    Stopping
+
+# this needs to be global, so it can be set in the Ctrl+C signal handler
+var bnStatus* = BeaconNodeStatus.Starting

beacon_chain/mainchain_monitor.nim

@@ -3,7 +3,8 @@ import
   chronos, web3, web3/ethtypes as web3Types, json, chronicles,
   eth/common/eth_types, eth/async_utils,
   spec/[datatypes, digest, crypto, beaconstate, helpers, validator],
-  network_metadata, merkle_minimal
+  network_metadata, merkle_minimal,
+  beacon_node_status
 
 from times import epochTime
 
@@ -564,8 +565,27 @@ proc findGenesisBlockInRange(m: MainchainMonitor,
 
   return endBlock
 
+proc safeCancel(fut: var Future[void]) =
+  if not fut.isNil and not fut.finished:
+    fut.cancel()
+    fut = nil
+
+proc stop*(m: MainchainMonitor) =
+  safeCancel m.runFut
+  safeCancel m.genesisMonitoringFut
+
+template checkIfShouldStopMainchainMonitor(m: MainchainMonitor) =
+  if bnStatus == BeaconNodeStatus.Stopping:
+    if not m.genesisStateFut.isNil:
+      m.genesisStateFut.complete()
+      m.genesisStateFut = nil
+    m.stop
+    return
+
 proc checkForGenesisLoop(m: MainchainMonitor) {.async.} =
   while true:
+    m.checkIfShouldStopMainchainMonitor()
+
     if not m.genesisState.isNil:
       return
 
@@ -636,6 +656,9 @@ proc waitGenesis*(m: MainchainMonitor): Future[BeaconStateRef] {.async.} =
     await m.genesisStateFut
     m.genesisStateFut = nil
 
+    if bnStatus == BeaconNodeStatus.Stopping:
+      return new BeaconStateRef # cannot return nil...
+
   if m.genesisState != nil:
     return m.genesisState
   else:
@@ -677,6 +700,8 @@ proc processDeposits(m: MainchainMonitor,
   # it could easily re-order the steps due to the intruptable
   # interleaved execution of async code.
   while true:
+    m.checkIfShouldStopMainchainMonitor()
+
     let blk = await m.depositQueue.popFirst()
     m.eth1Chain.trimHeight(Eth1BlockNumber(blk.number) - 1)
 
@@ -776,15 +801,6 @@ proc run(m: MainchainMonitor, delayBeforeStart: Duration) {.async.} =
   finally:
     await close(dataProvider)
 
-proc safeCancel(fut: var Future[void]) =
-  if not fut.isNil and not fut.finished:
-    fut.cancel()
-    fut = nil
-
-proc stop*(m: MainchainMonitor) =
-  safeCancel m.runFut
-  safeCancel m.genesisMonitoringFut
-
 proc start(m: MainchainMonitor, delayBeforeStart: Duration) =
   if m.runFut.isNil:
     let runFut = m.run(delayBeforeStart)