Address review feedback

eth/async_utils.nim

@@ -1,12 +1,20 @@
 import
-  chronos/asyncfutures2, chronicles
+  chronos/[asyncfutures2, asyncloop], chronicles
+
+proc catchOrQuit(error: Exception) =
+  if error of CatchableError:
+    trace "Async operation ended with a recoverable error", err = error.msg
+  else:
+    fatal "Fatal exception reached", err = error.msg
+    quit 1
 
 proc traceAsyncErrors*(fut: FutureBase) =
   fut.addCallback do (arg: pointer):
     if not fut.error.isNil:
-      if fut.error[] of CatchableError:
-        trace "Async operation ended with a recoverable error", err = fut.error.msg
-      else:
-        fatal "Fatal exception reached", err = fut.error.msg
-        quit 1
+      catchOrQuit fut.error[]
 
+template traceAwaitErrors*(fut: FutureBase) =
+  let f = fut
+  yield f
+  if not f.error.isNil:
+    catchOrQuit f.error[]

eth/p2p/rlpx.nim

@@ -1,6 +1,6 @@
 import
   macros, tables, algorithm, deques, hashes, options, typetraits,
-  std_shims/macros_shim, chronicles, nimcrypto, chronos, eth/[rlp, common, keys],
+  std_shims/macros_shim, chronicles, nimcrypto, chronos, eth/[rlp, common, keys, async_utils],
   private/p2p_types, kademlia, auth, rlpxcrypt, enode
 
 when useSnappy:
@@ -503,6 +503,12 @@ proc nextMsg*(peer: Peer, MsgType: type): Future[MsgType] =
   newFuture result
   peer.awaitedMessages[wantedId] = result
 
+# Known fatal errors are handled inside dispatchMessages.
+# Errors we are currently unaware of are caught in the dispatchMessages
+# callback. There they will be logged if CatchableError and quit on Defect.
+# Non fatal errors such as the current CatchableError could be moved and
+# handled a layer lower for clarity (and consistency), as also the actual
+# message handler code as the TODO mentions already.
 proc dispatchMessages*(peer: Peer) {.async.} =
   while true:
     var msgId: int
@@ -510,10 +516,10 @@ proc dispatchMessages*(peer: Peer) {.async.} =
     try:
       (msgId, msgData) = await peer.recvMsg()
     except TransportIncompleteError:
-      trace "Connection dropped in dispatchMessages"
+      trace "Connection dropped, ending dispatchMessages loop", peer
       # This can happen during the rlpx connection setup or at any point after.
       # Because this code does not know, a disconnect needs to be done.
-      asyncDiscard peer.disconnect(ClientQuitting)
+      await peer.disconnect(ClientQuitting)
       return
 
     if msgId == 1: # p2p.disconnect
@@ -525,8 +531,9 @@ proc dispatchMessages*(peer: Peer) {.async.} =
     try:
       await peer.invokeThunk(msgId, msgData)
     except RlpError:
-      debug "ending dispatchMessages loop", peer, err = getCurrentExceptionMsg()
-      await peer.disconnect(BreachOfProtocol)
+      debug "RlpError, ending dispatchMessages loop", peer,
+             err = getCurrentExceptionMsg()
+      await peer.disconnect(BreachOfProtocol, true)
       return
     except CatchableError:
       warn "Error while handling RLPx message", peer,
@@ -545,8 +552,10 @@ proc dispatchMessages*(peer: Peer) {.async.} =
         # TODO: Handling errors here must be investigated more carefully.
         # They also are supposed to be handled at the call-site where
         # `nextMsg` is used.
-        debug "nextMsg resolver failed", err = getCurrentExceptionMsg()
-        raise
+        debug "nextMsg resolver failed, ending dispatchMessages loop", peer,
+               err = getCurrentExceptionMsg()
+        await peer.disconnect(BreachOfProtocol, true)
+        return
       peer.awaitedMessages[msgId] = nil
 
 macro p2pProtocolImpl(name: static[string],
@@ -1167,13 +1176,13 @@ proc disconnect*(peer: Peer, reason: DisconnectionReason, notifyOtherPeer = fals
       yield fut
       if fut.failed:
         debug "Failed to delived disconnect message", peer
-    try:
+
     if not peer.dispatcher.isNil:
-        await callDisconnectHandlers(peer, reason)
-    except:
-      error "Exception in callDisconnectHandlers()",
-            err = getCurrentExceptionMsg()
-    finally:
+      # In case of `CatchableError` in any of the handlers, this will be logged.
+      # Other handlers will still execute.
+      # In case of `Defect` in any of the handlers, program will quit.
+      traceAwaitErrors callDisconnectHandlers(peer, reason)
+
     logDisconnectedPeer peer
     peer.connectionState = Disconnected
     removePeer(peer.network, peer)
@@ -1237,7 +1246,7 @@ proc postHelloSteps(peer: Peer, h: devp2p.hello) {.async.} =
     if messageProcessingLoop.failed:
       debug "Ending dispatchMessages loop", peer,
             err = messageProcessingLoop.error.msg
-      asyncDiscard peer.disconnect(ClientQuitting)
+      traceAsyncErrors peer.disconnect(ClientQuitting)
 
   # The handshake may involve multiple async steps, so we wait
   # here for all of them to finish.

tests/p2p/p2p_test_helper.nim

@@ -0,0 +1,34 @@
+import
+  unittest, chronos, eth/[keys, p2p], eth/p2p/[discovery, enode]
+
+var nextPort = 30303
+
+proc localAddress(port: int): Address =
+  let port = Port(port)
+  result = Address(udpPort: port, tcpPort: port, ip: parseIpAddress("127.0.0.1"))
+
+proc startDiscoveryNode(privKey: PrivateKey, address: Address,
+                        bootnodes: seq[ENode]): Future[DiscoveryProtocol] {.async.} =
+  result = newDiscoveryProtocol(privKey, address, bootnodes)
+  result.open()
+  await result.bootstrap()
+
+proc setupBootNode*(): Future[ENode] {.async.} =
+  let
+    bootNodeKey = newPrivateKey()
+    bootNodeAddr = localAddress(30301)
+    bootNode = await startDiscoveryNode(bootNodeKey, bootNodeAddr, @[])
+  result = initENode(bootNodeKey.getPublicKey, bootNodeAddr)
+
+proc setupTestNode*(capabilities: varargs[ProtocolInfo, `protocolInfo`]): EthereumNode =
+  let keys1 = newKeyPair()
+  result = newEthereumNode(keys1, localAddress(nextPort), 1, nil,
+                           addAllCapabilities = false)
+  nextPort.inc
+  for capability in capabilities:
+    result.addCapability capability
+
+template asyncTest*(name, body: untyped) =
+  test name:
+    proc scenario {.async.} = body
+    waitFor scenario()

tests/p2p/test_failing_handler.nim

@@ -8,31 +8,8 @@
 #            MIT license (LICENSE-MIT)
 
 import
-  unittest, tables, chronos, eth/[keys, p2p], eth/p2p/[discovery, enode]
-
-var nextPort = 30303
-
-proc localAddress(port: int): Address =
-  let port = Port(port)
-  result = Address(udpPort: port, tcpPort: port, ip: parseIpAddress("127.0.0.1"))
-
-proc startDiscoveryNode(privKey: PrivateKey, address: Address,
-                        bootnodes: seq[ENode]): Future[DiscoveryProtocol] {.async.} =
-  result = newDiscoveryProtocol(privKey, address, bootnodes)
-  result.open()
-  await result.bootstrap()
-
-proc setupBootNode(): Future[ENode] {.async.} =
-  let
-    bootNodeKey = newPrivateKey()
-    bootNodeAddr = localAddress(30301)
-    bootNode = await startDiscoveryNode(bootNodeKey, bootNodeAddr, @[])
-  result = initENode(bootNodeKey.getPublicKey, bootNodeAddr)
-
-template asyncTest(name, body: untyped) =
-  test name:
-    proc scenario {.async.} = body
-    waitFor scenario()
+  unittest, tables, chronos, eth/p2p,
+  ./p2p_test_helper
 
 type
   network = ref object
@@ -48,7 +25,7 @@ p2pProtocol abc(version = 1,
   onPeerDisconnected do (peer: Peer, reason: DisconnectionReason) {.gcsafe.}:
     peer.networkState.count -= 1
     if true:
-      raise newException(UnsupportedProtocol, "Fake abc exception")
+      raise newException(CatchableError, "Fake abc exception")
 
 p2pProtocol xyz(version = 1,
                 shortName = "xyz",
@@ -60,21 +37,13 @@ p2pProtocol xyz(version = 1,
   onPeerDisconnected do (peer: Peer, reason: DisconnectionReason) {.gcsafe.}:
     peer.networkState.count -= 1
     if true:
-      raise newException(UnsupportedProtocol, "Fake xyz exception")
+      raise newException(CatchableError, "Fake xyz exception")
 
-proc prepTestNode(): EthereumNode =
-  let keys1 = newKeyPair()
-  result = newEthereumNode(keys1, localAddress(nextPort), 1, nil,
-                           addAllCapabilities = false)
-  nextPort.inc
-  result.addCapability abc
-  result.addCapability xyz
-
-suite "Failing handlers":
+suite "Testing protocol handlers":
   asyncTest "Failing disconnect handler":
     let bootENode = waitFor setupBootNode()
-    var node1 = prepTestNode()
-    var node2 = prepTestNode()
+    var node1 = setupTestNode(abc, xyz)
+    var node2 = setupTestNode(abc, xyz)
     # node2 listening and node1 not, to avoid many incoming vs outgoing
     var node1Connected = node1.connectToNetwork(@[bootENode], false, true)
     var node2Connected = node2.connectToNetwork(@[bootENode], true, true)

tests/p2p/test_shh_connect.nim

@@ -8,52 +8,18 @@
 #            MIT license (LICENSE-MIT)
 
 import
-  sequtils, options, unittest, tables, chronos, eth/[rlp, keys, p2p],
-  eth/p2p/rlpx_protocols/[whisper_protocol], eth/p2p/[discovery, enode]
-
-const
-  useCompression = defined(useSnappy)
-
-var nextPort = 30303
-
-proc localAddress(port: int): Address =
-  let port = Port(port)
-  result = Address(udpPort: port, tcpPort: port, ip: parseIpAddress("127.0.0.1"))
-
-proc startDiscoveryNode(privKey: PrivateKey, address: Address,
-                        bootnodes: seq[ENode]): Future[DiscoveryProtocol] {.async.} =
-  result = newDiscoveryProtocol(privKey, address, bootnodes)
-  result.open()
-  await result.bootstrap()
-
-proc setupBootNode(): Future[ENode] {.async.} =
-  let
-    bootNodeKey = newPrivateKey()
-    bootNodeAddr = localAddress(30301)
-    bootNode = await startDiscoveryNode(bootNodeKey, bootNodeAddr, @[])
-  result = initENode(bootNodeKey.getPublicKey, bootNodeAddr)
-
-template asyncTest(name, body: untyped) =
-  test name:
-    proc scenario {.async.} = body
-    waitFor scenario()
+  sequtils, options, unittest, tables, chronos, eth/[keys, p2p],
+  eth/p2p/rlpx_protocols/[whisper_protocol],
+  ./p2p_test_helper
 
 proc resetMessageQueues(nodes: varargs[EthereumNode]) =
   for node in nodes:
     node.resetMessageQueue()
 
-proc prepTestNode(): EthereumNode =
-  let keys1 = newKeyPair()
-  result = newEthereumNode(keys1, localAddress(nextPort), 1, nil,
-                           addAllCapabilities = false,
-                           useCompression = useCompression)
-  nextPort.inc
-  result.addCapability Whisper
-
 let bootENode = waitFor setupBootNode()
 
-var node1 = prepTestNode()
-var node2 = prepTestNode()
+var node1 = setupTestNode(Whisper)
+var node2 = setupTestNode(Whisper)
 # node2 listening and node1 not, to avoid many incoming vs outgoing
 var node1Connected = node1.connectToNetwork(@[bootENode], false, true)
 var node2Connected = node2.connectToNetwork(@[bootENode], true, true)
@@ -352,7 +318,7 @@ suite "Whisper connections":
       node1.unsubscribeFilter(filter) == true
 
   test "Light node posting":
-    var ln1 = prepTestNode()
+    var ln1 = setupTestNode(Whisper)
     ln1.setLightNode(true)
 
     # not listening, so will only connect to others that are listening (node2)
@@ -373,8 +339,8 @@ suite "Whisper connections":
       ln1.protocolState(Whisper).queue.items.len == 0
 
   test "Connect two light nodes":
-    var ln1 = prepTestNode()
-    var ln2 = prepTestNode()
+    var ln1 = setupTestNode(Whisper)
+    var ln2 = setupTestNode(Whisper)
 
     ln1.setLightNode(true)
     ln2.setLightNode(true)