Switch cl-el comms to RpcChannel

Instead of using a socket (and having to open a fake connection between
EL and CL), this pr switches to
status-im/nim-json-rpc#254 for internal
communication.

Eventually, one could make this more efficient by skipping the JSON
step, but like this, we at least no longer have to open an Engine API
port which makes this setup more secure and easy to deploy (fewer open
ports).

There's also fewer potential errors to contend with and payloads don't
have to travel across the OS buffers and instead stay internal to the
process.

Author: arnetheduck

.gitmodules

@@ -238,3 +238,7 @@
 	path = vendor/nim-quic
 	url = https://github.com/vacp2p/nim-quic
 	branch = main
+[submodule "vendor/nim-async-channels"]
+	path = vendor/nim-async-channels
+	url = https://github.com/status-im/nim-async-channels
+	branch = master

execution_chain/conf.nim

@@ -447,6 +447,12 @@ type
         defaultValue: false
         name: "engine-api" .}: bool
 
+      engineApiChannelEnabled* {.
+        hidden
+        desc: "Enable the Engine API Channel"
+        defaultValue: false
+        name: "debug-engine-api-channel" .}: bool
+
       engineApiPort* {.
         desc: "Listening port for the Engine API(http and ws)"
         defaultValue: defaultEngineApiPort
@@ -755,7 +761,7 @@ func getAllowedOrigins*(config: ExecutionClientConf): seq[Uri] =
     result.add parseUri(item)
 
 func engineApiServerEnabled*(config: ExecutionClientConf): bool =
-  config.engineApiEnabled or config.engineApiWsEnabled
+  config.engineApiEnabled or config.engineApiWsEnabled or config.engineApiChannelEnabled
 
 func shareServerWithEngineApi*(config: ExecutionClientConf): bool =
   config.engineApiServerEnabled and

execution_chain/el_sync.nim

@@ -18,7 +18,8 @@ import
   web3/[engine_api, primitives, conversions],
   beacon_chain/consensus_object_pools/blockchain_dag,
   beacon_chain/el/[el_manager, engine_api_conversions],
-  beacon_chain/spec/[forks, presets, state_transition_block]
+  beacon_chain/spec/[forks, presets, state_transition_block],
+  json_rpc/client
 
 logScope:
   topics = "elsync"
@@ -87,24 +88,15 @@ proc findSlot(
 
   Opt.some importedSlot
 
-proc syncToEngineApi*(dag: ChainDAGRef, url: EngineApiUrl) {.async.} =
+proc syncToEngineApi*(dag: ChainDAGRef, rpcClient: RpcClient) {.async.} =
   # Takes blocks from the CL and sends them to the EL - the attempt is made
   # optimistically until something unexpected happens (reorg etc) at which point
   # the process ends
 
   let
     # Create the client for the engine api
-    # And exchange the capabilities for a test communication
-    web3 = await url.newWeb3()
-    rpcClient = web3.provider
     (lastEra1Block, firstSlotAfterMerge) = dag.cfg.loadNetworkConfig()
 
-  defer:
-    try:
-      await web3.close()
-    except:
-      discard
-
   # Load the EL state detials and create the beaconAPI client
   var elBlockNumber = uint64(await rpcClient.eth_blockNumber())
 

execution_chain/nimbus.nim

@@ -16,15 +16,15 @@ proc workaround*(): int {.exportc.} =
   return int(Future[Quantity]().internalValue)
 
 import
-  std/[os, net, options, strformat, terminal, typetraits],
+  std/[os, net, options, terminal, typetraits],
   stew/io2,
   chronos/threadsync,
   chronicles,
   metrics,
   metrics/chronos_httpserver,
-  nimcrypto/sysrand,
   eth/enr/enr,
   eth/net/nat,
+  json_rpc/rpcchannels,
   eth/p2p/discoveryv5/random2,
   beacon_chain/spec/[engine_authentication],
   beacon_chain/validators/keystore_management,
@@ -36,7 +36,6 @@ import
     nimbus_binary_common,
     process_state,
   ],
-  ./rpc/jwt_auth,
   ./[
     constants,
     conf as ecconf,
@@ -170,13 +169,13 @@ type
     tcpPort: Port
     udpPort: Port
     elSync: bool
+    channel: RpcChannelPtrs
 
   ExecutionThreadConfig = object
     tsp: ThreadSignalPtr
     tcpPort: Port
     udpPort: Option[Port]
-
-var jwtKey: JwtSharedKey
+    channel: RpcChannelPtrs
 
 proc dataDir*(config: NimbusConf): string =
   string config.dataDirFlag.get(
@@ -190,14 +189,14 @@ proc justWait(tsp: ThreadSignalPtr) {.async: (raises: [CancelledError]).} =
     notice "Waiting failed", err = exc.msg
 
 proc elSyncLoop(
-    dag: ChainDAGRef, url: EngineApiUrl
+    dag: ChainDAGRef, elManager: ELManager
 ) {.async: (raises: [CancelledError]).} =
   while true:
     await sleepAsync(12.seconds)
 
     # TODO trigger only when the EL needs syncing
     try:
-      await syncToEngineApi(dag, url)
+      await syncToEngineApi(dag, elManager.channel())
     except CatchableError as exc:
       # This can happen when the EL is busy doing some work, specially on
       # startup
@@ -208,17 +207,8 @@ proc runBeaconNode(p: BeaconThreadConfig) {.thread.} =
     stderr.writeLine error # Logging not yet set up
     quit QuitFailure
 
-  let engineUrl = EngineApiUrl.init(
-    &"http://127.0.0.1:{defaultEngineApiPort}/", Opt.some(@(distinctBase(jwtKey)))
-  )
-
   config.metricsEnabled = false
-  config.elUrls =
-    @[
-      EngineApiUrlConfigValue(
-        url: engineUrl.url, jwtSecret: some toHex(distinctBase(jwtKey))
-      )
-    ]
+  config.elUrls = @[EngineApiUrlConfigValue(channel: Opt.some(p.channel))]
   config.statusBarEnabled = false # Multi-threading issues due to logging
   config.tcpPort = p.tcpPort
   config.udpPort = p.udpPort
@@ -259,11 +249,8 @@ proc runBeaconNode(p: BeaconThreadConfig) {.thread.} =
 proc runExecutionClient(p: ExecutionThreadConfig) {.thread.} =
   var config = makeConfig(ignoreUnknown = true)
   config.metricsEnabled = false
-  config.engineApiEnabled = true
-  config.engineApiPort = Port(defaultEngineApiPort)
-  config.engineApiAddress = defaultAdminListenAddress
-  config.jwtSecret.reset()
-  config.jwtSecretValue = some toHex(distinctBase(jwtKey))
+  config.engineApiEnabled = false
+  config.engineApiChannelEnabled = true
   config.agentString = "nimbus"
   config.tcpPort = p.tcpPort
   config.udpPortFlag = p.udpPort
@@ -277,16 +264,14 @@ proc runExecutionClient(p: ExecutionThreadConfig) {.thread.} =
     com = setupCommonRef(config, taskpool)
 
   dynamicLogScope(comp = "ec"):
-    nimbus_execution_client.runExeClient(config, com, p.tsp.justWait())
+    nimbus_execution_client.runExeClient(
+      config, com, p.tsp.justWait(), channel = Opt.some p.channel
+    )
 
   # Stop the other thread as well, in case `runExeClient` stopped early
   waitFor p.tsp.fire()
 
 proc runCombinedClient() =
-  # Make it harder to connect to the (internal) engine - this will of course
-  # go away
-  discard randomBytes(distinctBase(jwtKey))
-
   const banner = "Nimbus v0.0.1"
 
   var config = NimbusConf.loadWithBanners(banner, copyright, [specBanner], true).valueOr:
@@ -325,6 +310,9 @@ proc runCombinedClient() =
       "Baked-in KZG setup is correct"
     )
 
+  var channel: RpcChannel
+  let pairs = channel.open().expect("working channel")
+
   var bnThread: Thread[BeaconThreadConfig]
   let bnStop = ThreadSignalPtr.new().expect("working ThreadSignalPtr")
   createThread(
@@ -335,6 +323,7 @@ proc runCombinedClient() =
       tcpPort: config.beaconTcpPort.get(config.tcpPort.get(Port defaultEth2TcpPort)),
       udpPort: config.beaconUdpPort.get(config.udpPort.get(Port defaultEth2TcpPort)),
       elSync: config.elSync,
+      channel: pairs.client,
     ),
   )
 
@@ -357,6 +346,7 @@ proc runCombinedClient() =
           some(Port(uint16(config.udpPort.get()) + 1))
         else:
           none(Port),
+      channel: pairs.server,
     ),
   )
 

execution_chain/nimbus_desc.nim

@@ -21,7 +21,8 @@ import
   ./sync/beacon as beacon_sync,
   ./sync/wire_protocol,
   ./beacon/beacon_engine,
-  ./common
+  ./common,
+  json_rpc/rpcchannels
 
 when enabledLogLevel == TRACE:
   import std/sequtils
@@ -42,6 +43,7 @@ type
   NimbusNode* = ref object
     httpServer*: NimbusHttpServerRef
     engineApiServer*: NimbusHttpServerRef
+    engineApiChannel*: RpcChannelServer
     ethNode*: EthereumNode
     fc*: ForkedChainRef
     txPool*: TxPoolRef

execution_chain/nimbus_execution_client.nim

@@ -185,24 +185,24 @@ proc setupP2P(nimbus: NimbusNode, config: ExecutionClientConf, com: CommonRef) =
   if not syncerShouldRun:
     nimbus.beaconSyncRef = BeaconSyncRef(nil)
 
-proc init*(nimbus: NimbusNode, config: ExecutionClientConf, com: CommonRef) =
+proc init*(nimbus: NimbusNode, config: ExecutionClientConf, com: CommonRef, channel: Opt[RpcChannelPtrs]) =
   nimbus.accountsManager = new AccountsManager
   nimbus.rng = newRng()
 
   basicServices(nimbus, config, com)
   manageAccounts(nimbus, config)
   setupP2P(nimbus, config, com)
-  setupRpc(nimbus, config, com)
+  setupRpc(nimbus, config, com, channel)
 
   # Not starting syncer if there is definitely no way to run it. This
   # avoids polling (i.e. waiting for instructions) and some logging.
   if not nimbus.beaconSyncRef.isNil and
       not nimbus.beaconSyncRef.start():
     nimbus.beaconSyncRef = BeaconSyncRef(nil)
 
-proc init*(T: type NimbusNode, config: ExecutionClientConf, com: CommonRef): T =
+proc init*(T: type NimbusNode, config: ExecutionClientConf, com: CommonRef, channel: Opt[RpcChannelPtrs]): T =
   let nimbus = T()
-  nimbus.init(config, com)
+  nimbus.init(config, com, channel)
   nimbus
 
 proc preventLoadingDataDirForTheWrongNetwork(db: CoreDbRef; config: ExecutionClientConf) =
@@ -274,16 +274,17 @@ proc runExeClient*(
     com: CommonRef,
     stopper: StopFuture,
     nimbus = NimbusNode(nil),
+    channel = Opt.none(RpcChannelPtrs),
 ) =
   ## Launches and runs the execution client for pre-configured `nimbus` and
   ## `conf` argument descriptors.
   ##
 
   var nimbus = nimbus
   if nimbus.isNil:
-    nimbus = NimbusNode.init(config, com)
+    nimbus = NimbusNode.init(config, com, channel)
   else:
-    nimbus.init(config, com)
+    nimbus.init(config, com, channel)
 
   defer:
     let

execution_chain/rpc.nim

@@ -12,7 +12,7 @@
 import
   chronicles,
   websock/websock,
-  json_rpc/rpcserver,
+  json_rpc/[rpcserver, rpcchannels],
   ./rpc/[common, cors, debug, engine_api, jwt_auth, rpc_server, server_api],
   ./[conf, nimbus_desc]
 
@@ -23,7 +23,8 @@ export
   jwt_auth,
   cors,
   rpc_server,
-  server_api
+  server_api,
+  rpcchannels
 
 const DefaultChunkSize = 1024*1024
 
@@ -53,7 +54,6 @@ func installRPC(server: RpcServer,
   if RpcFlag.Debug in flags:
     setupDebugRpc(com, nimbus.txPool, server)
 
-
 proc newRpcWebsocketHandler(): RpcWebSocketHandler =
   let rng = HmacDrbgContext.new()
   RpcWebSocketHandler(
@@ -198,8 +198,8 @@ proc addServices(handlers: var seq[RpcHandlerProc],
     handlers.addHandler(server)
 
 proc setupRpc*(nimbus: NimbusNode, config: ExecutionClientConf,
-               com: CommonRef) =
-  if not config.engineApiEnabled:
+               com: CommonRef, channel: Opt[RpcChannelPtrs]) =
+  if not config.engineApiEnabled and channel.isNone():
     warn "Engine API disabled, the node will not respond to consensus client updates (enable with `--engine-api`)"
 
   if not config.serverEnabled:
@@ -257,3 +257,10 @@ proc setupRpc*(nimbus: NimbusNode, config: ExecutionClientConf,
       quit(QuitFailure)
     nimbus.engineApiServer = res.get
     nimbus.engineApiServer.start()
+
+    if channel.isSome():
+      nimbus.engineApiChannel = RpcChannelServer.new(channel[])
+
+      setupEngineAPI(nimbus.beaconEngine, nimbus.engineApiChannel)
+      installRPC(nimbus.engineApiChannel, nimbus, config, com, serverApi, {RpcFlag.Eth})
+      nimbus.engineApiChannel.start()