close underlying bufferstream in lpchannel

libp2p/connection.nim

@@ -15,6 +15,9 @@ import peerinfo,
        varint,
        vbuffer
 
+logScope:
+  topic = "Connection"
+
 const DefaultReadSize* = 1 shl 20
 
 type
@@ -22,21 +25,23 @@ type
     peerInfo*: PeerInfo
     stream*: LPStream
     observedAddrs*: Multiaddress
+    maxReadSize: int
 
   InvalidVarintException = object of LPStreamError
   InvalidVarintSizeException = object of LPStreamError
 
 proc newInvalidVarintException*(): ref InvalidVarintException =
-  newException(InvalidVarintException, "unable to parse varint")
+  newException(InvalidVarintException, "Unable to parse varint")
 
 proc newInvalidVarintSizeException*(): ref InvalidVarintSizeException =
-  newException(InvalidVarintSizeException, "wrong varint size")
+  newException(InvalidVarintSizeException, "Wrong varint size")
 
-proc init*[T: Connection](self: var T, stream: LPStream) =
+proc init*[T: Connection](self: var T, stream: LPStream, maxReadSize = DefaultReadSize) =
   ## create a new Connection for the specified async reader/writer
   new self
   self.stream = stream
   self.closeEvent = newAsyncEvent()
+  self.maxReadSize = maxReadSize
 
   # bind stream's close event to connection's close
   # to ensure correct close propagation
@@ -45,7 +50,7 @@ proc init*[T: Connection](self: var T, stream: LPStream) =
     self.stream.closeEvent.wait().
       addCallback do (udata: pointer):
         if not this.closed:
-          trace "closing this connection because wrapped stream closed"
+          trace "wrapped stream closed, closing conn"
           asyncCheck this.close()
 
 proc newConnection*(stream: LPStream): Connection =
@@ -128,7 +133,7 @@ proc readLp*(s: Connection): Future[seq[byte]] {.async, gcsafe.} =
         break
     if res != VarintStatus.Success:
       raise newInvalidVarintException()
-    if size.int > DefaultReadSize:
+    if size.int > s.maxReadSize:
       raise newInvalidVarintSizeException()
     buff.setLen(size)
     if size > 0.uint:

libp2p/multistream.nim

@@ -154,7 +154,7 @@ proc handle*(m: MultistreamSelect, conn: Connection) {.async, gcsafe.} =
           warn "no handlers for ", protocol = ms
           await conn.write(m.na)
   except CatchableError as exc:
-    trace "exception occurred in MultistreamSelect.handle", exc = exc.msg
+    trace "Exception occurred", exc = exc.msg
   finally:
     trace "leaving multistream loop"
 

libp2p/muxers/mplex/lpchannel.nim

@@ -65,15 +65,22 @@ proc newChannel*(id: uint64,
 proc closeMessage(s: LPChannel) {.async.} =
   await s.conn.writeMsg(s.id, s.closeCode) # write header
 
-proc closedByRemote*(s: LPChannel) {.async.} =
-  s.closedRemote = true
-
 proc cleanUp*(s: LPChannel): Future[void] =
   # method which calls the underlying buffer's `close`
   # method used instead of `close` since it's overloaded to
   # simulate half-closed streams
   result = procCall close(BufferStream(s))
 
+proc tryCleanup(s: LPChannel) {.async, inline.} =
+  # if stream is EOF, then cleanup immediatelly
+  if s.closedRemote and s.len == 0:
+    await s.cleanUp()
+
+proc closedByRemote*(s: LPChannel) {.async.} =
+  s.closedRemote = true
+  if s.len == 0:
+    await s.cleanUp()
+
 proc open*(s: LPChannel): Future[void] =
   s.isOpen = true
   s.conn.writeMsg(s.id, MessageType.New, s.name)
@@ -88,11 +95,13 @@ proc resetMessage(s: LPChannel) {.async.} =
 proc resetByRemote*(s: LPChannel) {.async.} =
   await allFutures(s.close(), s.closedByRemote())
   s.isReset = true
+  await s.cleanUp()
 
 proc reset*(s: LPChannel) {.async.} =
   await allFutures(s.resetMessage(), s.resetByRemote())
 
 method closed*(s: LPChannel): bool =
+  trace "closing lpchannel", id = s.id, initiator = s.initiator
   result = s.closedRemote and s.len == 0
 
 proc pushTo*(s: LPChannel, data: seq[byte]): Future[void] =
@@ -107,57 +116,46 @@ proc pushTo*(s: LPChannel, data: seq[byte]): Future[void] =
 
   result = procCall pushTo(BufferStream(s), data)
 
-method read*(s: LPChannel, n = -1): Future[seq[byte]] =
+template raiseEOF(): untyped =
   if s.closed or s.isReset:
-    var retFuture = newFuture[seq[byte]]("LPChannel.read")
+    raise newLPStreamEOFError()
-    retFuture.fail(newLPStreamEOFError())
-    return retFuture
 
-  result = procCall read(BufferStream(s), n)
+method read*(s: LPChannel, n = -1): Future[seq[byte]] {.async.} =
+  raiseEOF()
+  result = (await procCall(read(BufferStream(s), n)))
+  await s.tryCleanup()
 
 method readExactly*(s: LPChannel,
                     pbytes: pointer,
                     nbytes: int):
-                    Future[void] =
+                    Future[void] {.async.} =
-  if s.closed or s.isReset:
+  raiseEOF()
-    var retFuture = newFuture[void]("LPChannel.readExactly")
+  await procCall readExactly(BufferStream(s), pbytes, nbytes)
-    retFuture.fail(newLPStreamEOFError())
+  await s.tryCleanup()
-    return retFuture
-
-  result = procCall readExactly(BufferStream(s), pbytes, nbytes)
 
 method readLine*(s: LPChannel,
                  limit = 0,
                  sep = "\r\n"):
-                 Future[string] =
+                 Future[string] {.async.} =
-  if s.closed or s.isReset:
+  raiseEOF()
-    var retFuture = newFuture[string]("LPChannel.readLine")
+  result = await procCall readLine(BufferStream(s), limit, sep)
-    retFuture.fail(newLPStreamEOFError())
+  await s.tryCleanup()
-    return retFuture
-
-  result = procCall readLine(BufferStream(s), limit, sep)
 
 method readOnce*(s: LPChannel,
                  pbytes: pointer,
                  nbytes: int):
-                 Future[int] =
+                 Future[int] {.async.} =
-  if s.closed or s.isReset:
+  raiseEOF()
-    var retFuture = newFuture[int]("LPChannel.readOnce")
+  result = await procCall readOnce(BufferStream(s), pbytes, nbytes)
-    retFuture.fail(newLPStreamEOFError())
+  await s.tryCleanup()
-    return retFuture
-
-  result = procCall readOnce(BufferStream(s), pbytes, nbytes)
 
 method readUntil*(s: LPChannel,
                   pbytes: pointer, nbytes: int,
                   sep: seq[byte]):
-                  Future[int] =
+                  Future[int] {.async.} =
-  if s.closed or s.isReset:
+  raiseEOF()
-    var retFuture = newFuture[int]("LPChannel.readUntil")
+  result = await procCall readOnce(BufferStream(s), pbytes, nbytes)
-    retFuture.fail(newLPStreamEOFError())
+  await s.tryCleanup()
-    return retFuture
-
-  result = procCall readOnce(BufferStream(s), pbytes, nbytes)
 
 template writePrefix: untyped =
   if s.isLazy and not s.isOpen:

libp2p/muxers/mplex/mplex.nim

@@ -123,7 +123,7 @@ method handle*(m: Mplex) {.async, gcsafe.} =
           m.getChannelList(initiator).del(id)
           break
   except CatchableError as exc:
-    trace "exception occurred", exception = exc.msg
+    trace "Exception occurred", exception = exc.msg
   finally:
     trace "stopping mplex main loop"
     if not m.connection.closed():

libp2p/protocols/identify.nim

@@ -19,7 +19,7 @@ import ../protobuf/minprotobuf,
        ../utility
 
 logScope:
-  topic = "identify"
+  topic = "Identify"
 
 const
   IdentifyCodec* = "/ipfs/id/1.0.0"
@@ -123,6 +123,7 @@ method init*(p: Identify) =
 proc identify*(p: Identify,
                conn: Connection,
                remotePeerInfo: PeerInfo): Future[IdentifyInfo] {.async, gcsafe.} =
+  trace "initiating identify"
   var message = await conn.readLp()
   if len(message) == 0:
     trace "identify: Invalid or empty message received!"

libp2p/protocols/pubsub/pubsubpeer.nim

@@ -63,7 +63,7 @@ proc handle*(p: PubSubPeer, conn: Connection) {.async.} =
       await p.handler(p, @[msg])
       p.recvdRpcCache.put($hexData.hash)
   except CatchableError as exc:
-    error "exception occurred in PubSubPeer.handle", exc = exc.msg
+    trace "Exception occurred in PubSubPeer.handle", exc = exc.msg
   finally:
     trace "exiting pubsub peer read loop", peer = p.id
     if not conn.closed():
@@ -101,7 +101,7 @@ proc send*(p: PubSubPeer, msgs: seq[RPCMsg]) {.async.} =
                                                         encoded = encodedHex
 
   except CatchableError as exc:
-    trace "exception occurred in PubSubPeer.send", exc = exc.msg
+    trace "Exception occurred in PubSubPeer.send", exc = exc.msg
 
 proc sendMsg*(p: PubSubPeer,
               peerId: PeerID,

libp2p/protocols/secure/secure.nim

@@ -42,7 +42,7 @@ proc readLoop(sconn: SecureConn, stream: BufferStream) {.async.} =
 
       await stream.pushTo(msg)
   except CatchableError as exc:
-    trace "exception occurred Secure.readLoop", exc = exc.msg
+    trace "Exception occurred Secure.readLoop", exc = exc.msg
   finally:
     if not sconn.closed:
       await sconn.close()
@@ -63,7 +63,8 @@ proc handleConn*(s: Secure, conn: Connection, initiator: bool = false): Future[C
       if not isNil(sconn) and not sconn.closed:
         asyncCheck sconn.close()
 
-  result.peerInfo = PeerInfo.init(sconn.peerInfo.publicKey.get())
+  if not isNil(sconn.peerInfo) and sconn.peerInfo.publicKey.isSome:
+    result.peerInfo = PeerInfo.init(sconn.peerInfo.publicKey.get())
 
 method init*(s: Secure) {.gcsafe.} =
   proc handle(conn: Connection, proto: string) {.async, gcsafe.} =

libp2p/stream/bufferstream.nim

@@ -31,7 +31,7 @@
 ## buffer goes below ``maxSize`` or more data becomes available.
 
 import deques, math
-import chronos
+import chronos, chronicles
 import ../stream/lpstream
 
 const DefaultBufferSize* = 1024
@@ -154,7 +154,12 @@ method readExactly*(s: BufferStream,
   ## If EOF is received and ``nbytes`` is not yet read, the procedure
   ## will raise ``LPStreamIncompleteError``.
   ##
-  var buff = await s.read(nbytes)
+  var buff: seq[byte]
+  try:
+    buff = await s.read(nbytes)
+  except LPStreamEOFError as exc:
+    trace "Exception occured", exc = exc.msg
+
   if nbytes > buff.len():
     raise newLPStreamIncompleteError()
 
@@ -362,9 +367,10 @@ proc `|`*(s: BufferStream, target: BufferStream): BufferStream =
 
 method close*(s: BufferStream) {.async.} =
   ## close the stream and clear the buffer
+  trace "closing bufferstream"
   for r in s.readReqs:
     if not(isNil(r)) and not(r.finished()):
-      r.cancel()
+      r.fail(newLPStreamEOFError())
   s.dataReadEvent.fire()
   s.readBuf.clear()
   s.closeEvent.fire()

libp2p/stream/chronosstream.nim

@@ -28,16 +28,24 @@ proc newChronosStream*(server: StreamServer,
   result.writer = newAsyncStreamWriter(client)
   result.closeEvent = newAsyncEvent()
 
+template withExceptions(body: untyped) =
+  try:
+    body
+  except TransportIncompleteError:
+    raise newLPStreamIncompleteError()
+  except TransportLimitError:
+    raise newLPStreamLimitError()
+  except TransportError as exc:
+    raise newLPStreamIncorrectError(exc.msg)
+  except AsyncStreamIncompleteError:
+    raise newLPStreamIncompleteError()
+
 method read*(s: ChronosStream, n = -1): Future[seq[byte]] {.async.} =
   if s.reader.atEof:
     raise newLPStreamEOFError()
 
-  try:
+  withExceptions:
     result = await s.reader.read(n)
-  except AsyncStreamReadError as exc:
-    raise newLPStreamReadError(exc.par)
-  except AsyncStreamIncorrectError as exc:
-    raise newLPStreamIncorrectError(exc.msg)
 
 method readExactly*(s: ChronosStream,
                     pbytes: pointer,
@@ -45,36 +53,22 @@ method readExactly*(s: ChronosStream,
   if s.reader.atEof:
     raise newLPStreamEOFError()
 
-  try:
+  withExceptions:
     await s.reader.readExactly(pbytes, nbytes)
-  except AsyncStreamIncompleteError:
-    raise newLPStreamIncompleteError()
-  except AsyncStreamReadError as exc:
-    raise newLPStreamReadError(exc.par)
-  except AsyncStreamIncorrectError as exc:
-    raise newLPStreamIncorrectError(exc.msg)
 
 method readLine*(s: ChronosStream, limit = 0, sep = "\r\n"): Future[string] {.async.} =
   if s.reader.atEof:
     raise newLPStreamEOFError()
 
-  try:
+  withExceptions:
     result = await s.reader.readLine(limit, sep)
-  except AsyncStreamReadError as exc:
-    raise newLPStreamReadError(exc.par)
-  except AsyncStreamIncorrectError as exc:
-    raise newLPStreamIncorrectError(exc.msg)
 
 method readOnce*(s: ChronosStream, pbytes: pointer, nbytes: int): Future[int] {.async.} =
   if s.reader.atEof:
     raise newLPStreamEOFError()
 
-  try:
+  withExceptions:
     result = await s.reader.readOnce(pbytes, nbytes)
-  except AsyncStreamReadError as exc:
-    raise newLPStreamReadError(exc.par)
-  except AsyncStreamIncorrectError as exc:
-    raise newLPStreamIncorrectError(exc.msg)
 
 method readUntil*(s: ChronosStream,
                   pbytes: pointer,
@@ -83,55 +77,29 @@ method readUntil*(s: ChronosStream,
   if s.reader.atEof:
     raise newLPStreamEOFError()
 
-  try:
+  withExceptions:
     result = await s.reader.readUntil(pbytes, nbytes, sep)
-  except AsyncStreamIncompleteError:
-    raise newLPStreamIncompleteError()
-  except AsyncStreamLimitError:
-    raise newLPStreamLimitError()
-  except LPStreamReadError as exc:
-    raise newLPStreamReadError(exc.par)
-  except AsyncStreamIncorrectError as exc:
-    raise newLPStreamIncorrectError(exc.msg)
 
 method write*(s: ChronosStream, pbytes: pointer, nbytes: int) {.async.} =
   if s.writer.atEof:
     raise newLPStreamEOFError()
 
-  try:
+  withExceptions:
     await s.writer.write(pbytes, nbytes)
-  except AsyncStreamWriteError as exc:
-    raise newLPStreamWriteError(exc.par)
-  except AsyncStreamIncompleteError:
-    raise newLPStreamIncompleteError()
-  except AsyncStreamIncorrectError as exc:
-    raise newLPStreamIncorrectError(exc.msg)
 
 method write*(s: ChronosStream, msg: string, msglen = -1) {.async.} =
   if s.writer.atEof:
     raise newLPStreamEOFError()
 
-  try:
+  withExceptions:
     await s.writer.write(msg, msglen)
-  except AsyncStreamWriteError as exc:
-    raise newLPStreamWriteError(exc.par)
-  except AsyncStreamIncompleteError:
-    raise newLPStreamIncompleteError()
-  except AsyncStreamIncorrectError as exc:
-    raise newLPStreamIncorrectError(exc.msg)
 
 method write*(s: ChronosStream, msg: seq[byte], msglen = -1) {.async.} =
   if s.writer.atEof:
     raise newLPStreamEOFError()
 
-  try:
+  withExceptions:
     await s.writer.write(msg, msglen)
-  except AsyncStreamWriteError as exc:
-    raise newLPStreamWriteError(exc.par)
-  except AsyncStreamIncompleteError:
-    raise newLPStreamIncompleteError()
-  except AsyncStreamIncorrectError as exc:
-    raise newLPStreamIncorrectError(exc.msg)
 
 method closed*(s: ChronosStream): bool {.inline.} =
   # TODO: we might only need to check for reader's EOF

libp2p/stream/lpstream.nim

@@ -51,24 +51,36 @@ proc newLPStreamEOFError*(): ref Exception {.inline.} =
 method closed*(s: LPStream): bool {.base, inline.} =
   s.isClosed
 
-method read*(s: LPStream, n = -1): Future[seq[byte]] {.base, async.} =
+method read*(s: LPStream,
+             n = -1):
+             Future[seq[byte]] {.base, async.} =
   doAssert(false, "not implemented!")
 
-method readExactly*(s: LPStream, pbytes: pointer,
+method readExactly*(s: LPStream,
-                    nbytes: int): Future[void] {.base, async.} =
+                    pbytes: pointer,
+                    nbytes: int):
+                    Future[void] {.base, async.} =
   doAssert(false, "not implemented!")
 
-method readLine*(s: LPStream, limit = 0, sep = "\r\n"): Future[string]
+method readLine*(s: LPStream,
+                 limit = 0,
+                 sep = "\r\n"):
+                 Future[string]
   {.base, async.} =
   doAssert(false, "not implemented!")
 
-method readOnce*(s: LPStream, pbytes: pointer, nbytes: int): Future[int]
+method readOnce*(s: LPStream,
+                 pbytes: pointer,
+                 nbytes: int):
+                 Future[int]
   {.base, async.} =
   doAssert(false, "not implemented!")
 
 method readUntil*(s: LPStream,
-                  pbytes: pointer, nbytes: int,
+                  pbytes: pointer,
-                  sep: seq[byte]): Future[int]
+                  nbytes: int,
+                  sep: seq[byte]):
+                  Future[int]
   {.base, async.} =
   doAssert(false, "not implemented!")
 

libp2p/switch.nim

@@ -285,7 +285,7 @@ proc start*(s: Switch): Future[seq[Future[void]]] {.async, gcsafe.} =
     try:
       await s.upgradeIncoming(conn) # perform upgrade on incoming connection
     except CatchableError as exc:
-      trace "exception occurred in Switch.start", exc = exc.msg
+      trace "Exception occurred in Switch.start", exc = exc.msg
     finally:
       if not isNil(conn) and not conn.closed:
         await conn.close()

libp2p/transports/transport.nim

@@ -62,7 +62,7 @@ method upgrade*(t: Transport) {.base, async, gcsafe.} =
 method handles*(t: Transport, address: MultiAddress): bool {.base, gcsafe.} =
   ## check if transport supportes the multiaddress
 
-  # by default we skip circuit addresses to avoid 
+  # by default we skip circuit addresses to avoid
   # having to repeat the check in every transport
   address.protocols.filterIt( it == multiCodec("p2p-circuit") ).len == 0
 

tests/testmplex.nim

@@ -193,7 +193,12 @@ suite "Mplex":
         proc handleMplexListen(stream: Connection) {.async, gcsafe.} =
           defer:
             await stream.close()
-          let msg = await stream.readLp()
+
+          try:
+            discard await stream.readLp()
+          except CatchableError:
+            return
+
           # we should not reach this anyway!!
           check false
           listenJob.complete()
@@ -217,12 +222,14 @@ suite "Mplex":
       var bigseq = newSeqOfCap[uint8](MaxMsgSize + 1)
       for _ in 0..<MaxMsgSize:
         bigseq.add(uint8(rand(uint('A')..uint('z'))))
-      await stream.writeLp(bigseq)
+
       try:
+        await stream.writeLp(bigseq)
         await listenJob.wait(millis(500))
       except AsyncTimeoutError:
         # we want to time out here!
         discard
+
       result = true
 
     check:
@@ -359,24 +366,18 @@ suite "Mplex":
     expect LPStreamEOFError:
       waitFor(testClosedForWrite())
 
-  # TODO: this locks up after removing sleepAsync as a
+  test "half closed - channel should close for read by remote":
-  # synchronization mechanism in mplex. I believe this
+    proc testClosedForRead(): Future[void] {.async.} =
-  # is related to how chronos schedules callbacks in select,
+      proc writeHandler(data: seq[byte]) {.async, gcsafe.} = discard
-  # which effectively puts to infinite sleep when there
+      let chann = newChannel(1, newConnection(newBufferStream(writeHandler)), true)
-  # are no more callbacks, so essentially this sequence of
-  # reads isn't possible with the current chronos.
-  # test "half closed - channel should close for read by remote":
-  #   proc testClosedForRead(): Future[void] {.async.} =
-  #     proc writeHandler(data: seq[byte]) {.async, gcsafe.} = discard
-  #     let chann = newChannel(1, newConnection(newBufferStream(writeHandler)), true)
 
-  #     await chann.pushTo(cast[seq[byte]]("Hello!"))
+      await chann.pushTo(cast[seq[byte]]("Hello!"))
-  #     await chann.closedByRemote()
+      await chann.closedByRemote()
-  #     discard await chann.read() # this should work, since there is data in the buffer
+      discard await chann.read() # this should work, since there is data in the buffer
-  #     discard await chann.read() # this should throw
+      discard await chann.read() # this should throw
 
-  #   expect LPStreamEOFError:
+    expect LPStreamEOFError:
-  #     waitFor(testClosedForRead())
+      waitFor(testClosedForRead())
 
   test "jitter - channel should be able to handle erratic read/writes":
     proc test(): Future[bool] {.async.} =

tests/testswitch.nim

@@ -17,7 +17,8 @@ import ../libp2p/[switch,
                   muxers/mplex/mplex,
                   muxers/mplex/types,
                   protocols/secure/secio,
-                  protocols/secure/secure]
+                  protocols/secure/secure,
+                  stream/lpstream]
 
 when defined(nimHasUsed): {.used.}
 
@@ -26,16 +27,6 @@ const TestCodec = "/test/proto/1.0.0"
 type
   TestProto = ref object of LPProtocol
 
-method init(p: TestProto) {.gcsafe.} =
-  proc handle(conn: Connection, proto: string) {.async, gcsafe.} =
-    let msg = cast[string](await conn.readLp())
-    check "Hello!" == msg
-    await conn.writeLp("Hello!")
-    await conn.close()
-
-  p.codec = TestCodec
-  p.handler = handle
-
 proc createSwitch(ma: MultiAddress): (Switch, PeerInfo) =
   var peerInfo: PeerInfo = PeerInfo.init(PrivateKey.random(RSA))
   peerInfo.addrs.add(ma)
@@ -67,21 +58,33 @@ suite "Switch":
 
       (switch1, peerInfo1) = createSwitch(ma1)
 
+      proc handle(conn: Connection, proto: string) {.async, gcsafe.} =
+        let msg = cast[string](await conn.readLp())
+        check "Hello!" == msg
+        await conn.writeLp("Hello!")
+        await conn.close()
+
       let testProto = new TestProto
-      testProto.init()
       testProto.codec = TestCodec
+      testProto.handler = handle
       switch1.mount(testProto)
+
       (switch2, peerInfo2) = createSwitch(ma2)
       awaiters.add(await switch1.start())
       awaiters.add(await switch2.start())
+
       let conn = await switch2.dial(switch1.peerInfo, TestCodec)
-      await conn.writeLp("Hello!")
+
-      let msg = cast[string](await conn.readLp())
+      try:
-      check "Hello!" == msg
+        await conn.writeLp("Hello!")
+        let msg = cast[string](await conn.readLp())
+        check "Hello!" == msg
+        result = true
+      except LPStreamError:
+        result = false
 
       await allFutures(switch1.stop(), switch2.stop())
       await allFutures(awaiters)
-      result = true
 
     check:
       waitFor(testSwitch()) == true
@@ -97,22 +100,33 @@ suite "Switch":
 
       (switch1, peerInfo1) = createSwitch(ma1)
 
+      proc handle(conn: Connection, proto: string) {.async, gcsafe.} =
+        let msg = cast[string](await conn.readLp())
+        check "Hello!" == msg
+        await conn.writeLp("Hello!")
+        await conn.close()
+
       let testProto = new TestProto
-      testProto.init()
       testProto.codec = TestCodec
+      testProto.handler = handle
       switch1.mount(testProto)
+
       (switch2, peerInfo2) = createSwitch(ma2)
       awaiters.add(await switch1.start())
       awaiters.add(await switch2.start())
       await switch2.connect(switch1.peerInfo)
       let conn = await switch2.dial(switch1.peerInfo, TestCodec)
-      await conn.writeLp("Hello!")
+
-      let msg = cast[string](await conn.readLp())
+      try:
-      check "Hello!" == msg
+        await conn.writeLp("Hello!")
+        let msg = cast[string](await conn.readLp())
+        check "Hello!" == msg
+        result = true
+      except LPStreamError:
+        result = false
 
       await allFutures(switch1.stop(), switch2.stop())
       await allFutures(awaiters)
-      result = true
 
     check:
       waitFor(testSwitch()) == true