feat: gRPC to dump heap (#506)

lib/Boltz.ts

@@ -150,7 +150,7 @@ class Boltz {
       this.grpcServer = new GrpcServer(
         this.logger,
         this.config.grpc,
-        new GrpcService(this.service),
+        new GrpcService(this.logger, this.service),
       );
 
       this.prometheus = new Prometheus(

lib/HeapDump.ts

@@ -0,0 +1,15 @@
+import fs from 'fs';
+import { getHeapSnapshot } from 'v8';
+
+export const dumpHeap = async (filePath: string) =>
+  new Promise<void>((resolve, reject) => {
+    const snapshot = getHeapSnapshot();
+    const fileStream = fs.createWriteStream(filePath);
+    snapshot.pipe(fileStream);
+
+    fileStream.on('finish', () => {
+      fileStream.end();
+      resolve();
+    });
+    fileStream.on('error', (err) => reject(err));
+  });

lib/cli/commands/DevHeapDump.ts

@@ -0,0 +1,21 @@
+import { Arguments } from 'yargs';
+import { DevHeapDumpRequest } from '../../proto/boltzrpc_pb';
+import { callback, loadBoltzClient } from '../Command';
+
+export const command = 'dev-heapdump [path]';
+
+export const describe = 'dumps the heap of the daemon into a file';
+
+export const builder = {
+  path: {
+    type: 'string',
+    describe: 'path to which the heap should be dumped',
+  },
+};
+
+export const handler = (argv: Arguments<any>): void => {
+  const request = new DevHeapDumpRequest();
+  request.setPath(argv.path);
+
+  loadBoltzClient(argv).devHeapDump(request, callback());
+};

lib/grpc/GrpcServer.ts

@@ -29,6 +29,7 @@ class GrpcServer {
       sweepSwaps: grpcService.sweepSwaps,
       rescan: grpcService.rescan,
       setSwapStatus: grpcService.setSwapStatus,
+      devHeapDump: grpcService.devHeapDump,
     });
   }
 

lib/grpc/GrpcService.ts

@@ -1,13 +1,18 @@
 import { handleUnaryCall } from '@grpc/grpc-js';
 import { Transaction as TransactionLiquid } from 'liquidjs-lib';
 import { parseTransaction } from '../Core';
-import { getHexString } from '../Utils';
+import { dumpHeap } from '../HeapDump';
+import Logger from '../Logger';
+import { getHexString, getUnixTime } from '../Utils';
 import { CurrencyType } from '../consts/Enums';
 import * as boltzrpc from '../proto/boltzrpc_pb';
 import Service from '../service/Service';
 
 class GrpcService {
-  constructor(private service: Service) {}
+  constructor(
+    private readonly logger: Logger,
+    private readonly service: Service,
+  ) {}
 
   public getInfo: handleUnaryCall<
     boltzrpc.GetInfoRequest,
@@ -233,6 +238,21 @@ class GrpcService {
     });
   };
 
+  public devHeapDump: handleUnaryCall<
+    boltzrpc.DevHeapDumpRequest,
+    boltzrpc.DevHeapDumpResponse
+  > = async (call, callback) => {
+    await this.handleCallback(call, callback, async () => {
+      const filePath =
+        call.request.getPath() || `${getUnixTime()}.heapsnapshot`;
+
+      this.logger.verbose(`Dumping heap at: ${filePath}`);
+      await dumpHeap(filePath);
+
+      return new boltzrpc.DevHeapDumpResponse();
+    });
+  };
+
   private handleCallback = async <R, T>(
     call: R,
     callback: (error: any, res: T | null) => void,