feat(rpc): add GetNodeInfo call (#570)

This creates a new rpc call named `GetNodeInfo` which is designed to
retrieve information about a particular node. Currently the only
information returned is the node's reputation score.

Closes #529.

lib/cli/commands/getnodeinfo.ts

@@ -0,0 +1,20 @@
+import { Arguments } from 'yargs';
+import { callback, loadXudClient } from '../command';
+import { GetNodeInfoRequest } from '../../proto/xudrpc_pb';
+
+export const command = 'getnodeinfo <node_pub_key>';
+
+export const describe = 'get general information about a node';
+
+export const builder = {
+  node_pub_key: {
+    type: 'string',
+    description: 'nodePubKey of node to get reputation',
+  },
+};
+
+export const handler = (argv: Arguments) => {
+  const request = new GetNodeInfoRequest();
+  request.setNodePubKey(argv.node_pub_key);
+  loadXudClient(argv).getNodeInfo(request, callback);
+};

lib/grpc/GrpcServer.ts

@@ -26,6 +26,7 @@ class GrpcServer {
       ban: grpcService.ban,
       unban: grpcService.unban,
       getInfo: grpcService.getInfo,
+      getNodeInfo: grpcService.getNodeInfo,
       getOrders: grpcService.getOrders,
       listCurrencies: grpcService.listCurrencies,
       listPairs: grpcService.listPairs,

lib/grpc/GrpcService.ts

@@ -296,6 +296,21 @@ class GrpcService {
     }
   }
 
+  /**
+   * See [[Service.getNodeInfo]]
+   */
+  public getNodeInfo: grpc.handleUnaryCall<xudrpc.GetNodeInfoRequest, xudrpc.GetNodeInfoResponse> = async (call, callback) => {
+    try {
+      const { banned, reputationScore } = await this.service.getNodeInfo(call.request.toObject());
+      const response = new xudrpc.GetNodeInfoResponse();
+      response.setBanned(banned);
+      response.setReputationscore(reputationScore);
+      callback(null, response);
+    } catch (err) {
+      callback(this.getGrpcError(err), null);
+    }
+  }
+
   /**
    * See [[Service.getOrders]]
    */

lib/p2p/Pool.ts

@@ -15,6 +15,7 @@ import addressUtils from '../utils/addressUtils';
 import { getExternalIp, UriParts } from '../utils/utils';
 import assert from 'assert';
 import { ReputationEvent } from '../types/enums';
+import { ReputationEventInstance } from '../types/db';
 
 type PoolConfig = {
   /** Whether or not to automatically detect and share current external ip address on startup. */
@@ -36,6 +37,11 @@ type PoolConfig = {
   addresses: string[];
 };
 
+type NodeReputationInfo = {
+  reputationScore: ReputationEvent;
+  banned: boolean;
+};
+
 interface Pool {
   on(event: 'packet.order', listener: (order: StampedPeerOrder) => void): this;
   on(event: 'packet.getOrders', listener: (peer: Peer, reqId: string, pairIds: string[]) => void): this;
@@ -281,6 +287,25 @@ class Pool extends EventEmitter {
     return false;
   }
 
+  /**
+   * Gets a node's reputation score and whether it is banned
+   * @param nodePubKey The node pub key of the node for which to get reputation information
+   * @return true if the specified node exists and the event was added, false otherwise
+   */
+  public getNodeReputation = async (nodePubKey: string): Promise<NodeReputationInfo> => {
+    const node = await this.repository.getNode(nodePubKey);
+    if (node) {
+      const { reputationScore, banned } = node;
+      return {
+        reputationScore,
+        banned,
+      };
+    } else {
+      this.logger.warn(`node ${nodePubKey} not found`);
+      throw errors.NODE_UNKNOWN(nodePubKey);
+    }
+  }
+
   /**
    * Attempt to add an outbound peer by connecting to a given socket address.
    * Throws an error if a connection to a node with the given nodePubKey exists or