[FEATURE] Stub for bridge client (#739)

* [FEATURE] Stub for bridge client

* [FEATURE] Add client to fluffy runner

* [FEATURE] Fix params in logs

* [FEATURE] Rename config option

fluffy/conf.nim

@@ -87,6 +87,11 @@ type
       defaultValue: DefaultAdminListenAddress
       name: "rpc-address" }: ValidIpAddress
 
+    bridgeUri* {.
+      defaultValue: none(string)
+      desc: "if provided, enables getting data from bridge node"
+      name: "bridge-client-uri" .}: Option[string]
+
     case cmd* {.
       command
       defaultValue: noCommand .}: PortalCmd

fluffy/fluffy.nim

@@ -9,11 +9,27 @@
 
 import
   confutils, confutils/std/net, chronicles, chronicles/topics_registry,
-  chronos, metrics, metrics/chronos_httpserver, json_rpc/servers/httpserver,
+  chronos, metrics, metrics/chronos_httpserver, json_rpc/clients/httpclient, json_rpc/servers/httpserver,
   eth/keys, eth/net/nat,
   eth/p2p/discoveryv5/protocol as discv5_protocol,
   eth/p2p/portal/protocol as portal_protocol,
-  ./conf, ./rpc/eth_api
+  ./conf, ./rpc/eth_api, ./rpc/bridge_client
+
+
+proc initializeBridgeClient(maybeUri: Option[string]): Option[BridgeClient] =
+  try:
+    if (maybeUri.isSome()):
+      let uri = maybeUri.unsafeGet()
+      # TODO: Add possiblity to start client on differnt transports based on uri.
+      let httpClient = newRpcHttpClient()
+      waitFor httpClient.connect(uri)
+      notice "Initialized bridge client:", uri = uri
+      return some[BridgeClient](httpClient)
+    else:
+      return none(BridgeClient)
+  except CatchableError as err:
+    notice "Failed to initialize bridge client", error = err.msg
+    return none(BridgeClient)
 
 proc run(config: PortalConf) {.raises: [CatchableError, Defect].} =
   let
@@ -58,6 +74,8 @@ proc run(config: PortalConf) {.raises: [CatchableError, Defect].} =
     rpcHttpServer.installEthApiHandlers()
     rpcHttpServer.start()
 
+  let bridgeClient = initializeBridgeClient(config.bridgeUri)
+
   d.start()
 
   runForever()

fluffy/rpc/bridge_client.nim

@@ -0,0 +1,35 @@
+# Nimbus
+# Copyright (c) 2021 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.
+
+{.push raises: [Defect].}
+
+import 
+  std/json,
+  eth/common, chronos, json_rpc/rpcclient
+
+# Specification of api https://github.com/ethereum/stateless-ethereum-specs/blob/master/portal-bridge-nodes.md#api
+# TODO after nethermind plugin will be ready we can get few responses from those endpoints, to create mock client to test if we
+# properly parse respones
+type
+  BridgeClient* = RpcClient
+
+# bridge_waitNewCanonicalChain
+proc waitNewCanonicalChain*(bridgeClient: BridgeClient): Future[void] {.async, raises: [Defect, CatchableError].} = discard
+
+#bridge_getBlockChanges
+proc getBlockChanges*(bridgeClient: BridgeClient, blockHash: Hash256): Future[AccessList] {.async, raises: [Defect, CatchableError].} = discard
+
+#bridge_getItemWitness"
+proc getItemWitness*(bridgeClient: BridgeClient, blockHash: Hash256, acctAddr: EthAddress, slotAddr: StorageKey):
+  Future[seq[seq[byte]]] {.async, raises: [Defect, CatchableError].} = discard
+
+#bridge_getNextItem
+proc getNextItem*(bridgeClient: BridgeClient, blockHash: Hash256, acctAddr: EthAddress, slotAddr: StorageKey):
+  Future[(EthAddress, StorageKey)] {.async, raises: [Defect, CatchableError].} = discard
+
+proc close*(bridgeClient: BridgeClient): Future[void] {.async, raises: [Defect, CatchableError].} = 
+  await bridgeClient.close()