pezkuwi-telemetry/packages/backend/src/message.ts

import { Data } from 'ws';
import { Maybe, Types } from '@dotstats/common';

export function parseMessage(data: Data): Maybe<Message> {
  try {
    const message = JSON.parse(data.toString());

    if (message && typeof message.msg === 'string' && typeof message.ts === 'string') {
      message.ts = new Date(message.ts);

      return message;
    }
  } catch (_) {
    console.warn('Error parsing message JSON');
  }

  return null;
}

export function getBestBlock(message: Message): Maybe<BestBlock> {
  switch (message.msg) {
    case 'node.start':
    case 'system.interval':
    case 'block.import':
      return message;
    default:
      return null;
  }
}

interface MessageBase {
  ts: Date,
  level: 'INFO' | 'WARN',
}

export interface BestBlock {
  best: Types.BlockHash,
  height: Types.BlockNumber,
  ts: Date,
}

interface SystemConnected {
  msg: 'system.connected',
  name: Types.NodeName,
  chain: Types.ChainLabel,
  config: string,
  implementation: Types.NodeImplementation,
  version: Types.NodeVersion,
}

export interface SystemInterval extends BestBlock {
  msg: 'system.interval',
  txcount: Types.TransactionCount,
  peers: Types.PeerCount,
  status: 'Idle' | string, // TODO: 'Idle' | ...?
}

interface NodeStart extends BestBlock {
  msg: 'node.start',
}

interface BlockImport extends BestBlock {
  msg: 'block.import',
}

// Union type
export type Message = MessageBase & (
  SystemConnected |
  SystemInterval  |
  NodeStart       |
  BlockImport
);


// received: {"msg":"block.import","level":"INFO","ts":"2018-06-18T17:30:35.285406538+02:00","best":"3d4fdc7960078ddc9be87dddc48324a6d64afdf1f65fffe89529ce9965cd5f29","height":526}
// received: {"msg":"node.start","level":"INFO","ts":"2018-06-18T17:30:40.038731057+02:00","best":"3d4fdc7960078ddc9be87dddc48324a6d64afdf1f65fffe89529ce9965cd5f29","height":526}
// received: {"msg":"system.connected","level":"INFO","ts":"2018-06-18T17:30:40.038975471+02:00","chain":"dev","config":"","version":"0.2.0","implementation":"parity-polkadot","name":"Majestic Widget"}
// received: {"msg":"system.interval","level":"INFO","ts":"2018-06-19T14:00:05.091355364+02:00","txcount":0,"best":"360c9563857308703398f637932b7ffe884e5c7b09692600ff09a4d753c9d948","height":7559,"peers":0,"status":"Idle"}