ZumCoind High-Availability Daemon Wrapper

This project is designed to wrap the ZumCoind daemon on a *nix system and monitor it for hangups, locks, fork, or other events that cause the daemon to stop responding to requests in an accurate manner.

The sample service.js includes how to automatically restart the daemon if it hangs, locks, or otherwise stops responding.

Table of Contents

1. Dependencies
2. Easy Start
3. Keep it Running
4. Documentation
   1. Methods
   2. Events
   3. ZumCoind RPC API Interface
   4. WebSocket Connections

Dependencies

• NodeJS v8.x
• ZumCoind v1.2.0 or higher

Easy Start

You must copy ZumCoind into the zumcoind-ha folder for the easy start process to occur.

git clone https://github.com/zumcoin-org/zumcoind-ha.git
cd zumcoind-ha
cp <ZumCoind> .
sudo npm install & node service.js

It is highly recommended that you use checkpoints when starting fresh or you'll need to wait a while for the sync to occur.

Keep it Running

I'm a big fan of PM2 so if you don't have it installed, the setup is quite simple.

npm install -g pm2

pm2 startup
pm2 install pm2-logrotate

pm2 start service.js --name zumcoind
pm2 save

Documentation

Initialization

Practically all ZumCoind command line arguments are exposed in the constructor method. Simply include them in your list of options to get activate or use them. Default values are defined below.

var daemon = new ZumCoind({
  // These are our ZumCoind-ha options
  pollingInterval: 10000, // How often to check the daemon in milliseconds
  maxPollingFailures: 3, // How many polling intervals can fail before we emit a down event?
  checkHeight: true, // Check the daemon block height against known trusted nodes
  maxDeviance: 5, // What is the maximum difference between our block height and the network height that we're willing to accept?
  clearP2pOnStart: true, // Will automatically delete the p2pstate.bin file on start if set to true
  clearDBLockFile: true, // Will automatically delete the DB LOCK file on start if set to true
  timeout: 2000, // How long to wait for RPC responses in milliseconds
  enableWebSocket: true, // Enables a socket.io websocket server on the rpcBindPort + 4 (e.g 17935 + 4 = 17939)
  webSocketPassword: false, // Set this to a password to use for the privileged socket events.

  // These are the standard ZumCoind options
  path: './ZumCoind', // Where can I find ZumCoind?
  dataDir: '~/.ZumCoin', // Where do you store your blockchain?
  testnet: false, // Use the testnet?
  enableCors: false, // Enable CORS support for the domain in this value
  enableBlockExplorer: true, // Enable the block explorer
  loadCheckpoints: false, // If set to a path to a file, will supply that file to the daemon if it exists.
  rpcBindIp: '0.0.0.0', // What IP to bind the RPC server to
  rpcBindPort: 17935, // What Port to bind the RPC server to
  p2pBindIp: '0.0.0.0', // What IP to bind the P2P network to
  p2pBindPort: 17936, // What Port to bind the P2P network to
  p2pExternalPort: 0, // What External Port to bind the P2P network to for those behind NAT
  allowLocalIp: false, // Add our own IP to the peer list?
  peers: false, // Manually add the peer(s) to the list. Allows for a string or an Array of strings.
  priorityNodes: false, // Manually add the priority node(s) to the peer list. Allows for a string or an Array of strings.
  exclusiveNodes: false, // Only add these node(s) to the peer list. Allows for a string or an Array of strings.
  seedNode: false, // Connect to this node to get the peer list then quit. Allows for a string.
  hideMyPort: false, // Hide from the rest of the network
  dbThreads: 2, // Number of database background threads
  dbMaxOpenFiles: 100, // Number of allowed open files for the DB
  dbWriteBufferSize: 256, // Size of the DB write buffer in MB
  dbReadCacheSize: 10, // Size of the DB read cache in MB
  feeAddress: false, // allows to specify the fee address for the node
  feeAmount: 0 // allows to specify the fee amount for the node
})

Methods

daemon.api.start()

Starts up the daemon and starts monitoring the process.

daemon.start()

daemon.api.stop()

Stops the daemon and halts all monitoring processes.

daemon.stop()

daemon.api.write(text)

Allows you to send a line of text to the daemon console

daemon.write('help')

Events

Event - block

This is emitted whenever a new block is found on the network (or locally).

daemon.on('block', (blockInfo) => {
  // do something
})

Sample data

{
  "alreadyGeneratedCoins": "1484230931125",
  "alreadyGeneratedTransactions": 974921,
  "baseReward": 2935998,
  "blockSize": 48846,
  "depth": 0,
  "difficulty": 358164537,
  "effectiveSizeMedian": 100000,
  "hash": "f11580d74134ac34673c74f8da458080aacbe1eccea05b197e9d10bde05139f5",
  "height": 501854,
  "major_version": 4,
  "minor_version": 0,
  "nonce": 214748383,
  "orphan_status": false,
  "penalty": 0,
  "prev_hash": "674046ea53a8673c630bd34655c4723199e69fdcfd518503f4c714e16a7121b5",
  "reward": 2936608,
  "sizeMedian": 231,
  "timestamp": 1527891820,
  "totalFeeAmount": 610,
  "transactions": [
    {
      "amount_out": 2936608,
      "fee": 0,
      "hash": "61b29d7a3fe931928388f14cffb5e705a68db219e1df6b4e15aee39d1c2a16e8",
      "size": 266
    },
    {
      "amount_out": 2005890,
      "fee": 110,
      "hash": "8096a55ccd0d4a736b3176836429905f349c3de53dd4e92d34f4a2db7613dc4b",
      "size": 2288
    },
    {
      "amount_out": 3999900,
      "fee": 100,
      "hash": "304a068cbe87cd02b48f80f8831197174b133870d0c118d1fe65d07a33331c4e",
      "size": 2691
    },
    {
      "amount_out": 7862058,
      "fee": 100,
      "hash": "29c0d6708e8148eec6e02173b3bab0093768e5f486f553939495a47f883b4445",
      "size": 9638
    },
    {
      "amount_out": 6951392,
      "fee": 100,
      "hash": "fe661f11a0ba9838610c147f70813c17755ab608c7b033f6432c0b434671182c",
      "size": 10004
    },
    {
      "amount_out": 6800150,
      "fee": 100,
      "hash": "4b0366f79ec341cf60d5ef8c9dd8e65974dacb1be1d30dc0bf11d2d9d8240b46",
      "size": 11493
    },
    {
      "amount_out": 7260417,
      "fee": 100,
      "hash": "066b86268b7bb2f780ed76f452d1e6f7213dc6cae273b71fbd4ba378befaed00",
      "size": 12155
    }
  ],
  "transactionsCumulativeSize": 48535
}

Event - data

Feeds back the stdout of the daemon process on a line by line basis. You can use this to monitor the progress of the application or hook and do your own development.

daemon.on('data', (data) => {
  // do something
})

Event - desync

This event is emitted when the daemon has lost synchronization with the ZumCoin network

daemon.on('descync', (daemonHeight, networkHeight, deviance) => {
  // do something
})

Event - down

This event is emitted when the daemon is not responding to RPC requests or local console checks. We believe at that point that the daemon is hung.

daemon.on('down', () => {
  // do something
})

Event - error

This event is emitted when the daemon or our service encounters an error.

daemon.on('error', (err) => {
  // do something
})

Event - info

This event is emitted when the daemon or our service has something to tell you but its not that important.

daemon.on('info', (info) => {
  // do something
})

Event - ready

This event is emitted when the daemon is synchronized with the ZumCoin network and is passing all the checks we have for it. It returns the equivalent of a /getinfo call to the RPC server with a few minor additions.

daemon.on('ready', (info) => {
  // do something
})

Sample Data

{
  "alt_blocks_count": 1,
  "difficulty": 250799029,
  "grey_peerlist_size": 4995,
  "hashrate": 8359967,
  "height": 502282,
  "incoming_connections_count": 8,
  "last_known_block_index": 340143,
  "network_height": 502282,
  "outgoing_connections_count": 8,
  "status": "OK",
  "synced": true,
  "tx_count": 473402,
  "tx_pool_size": 0,
  "version": "0.5.0",
  "white_peerlist_size": 602
}

Event - start

This event is emitted when the daemon starts. The callback contains the command line arguments supplied to ZumCoind.

daemon.on('start', (executablePath, args) => {
  // do something
})

Event - started

This event is emitted when the daemon is now accepting P2P connections.

daemon.on('started', () => {
  // do something
})

Event - stopped

This event is emitted when the daemon is stopped for whatever reason.

daemon.on('stopped', () => {
  // do something
})

Event - synced

This event is emitted when the daemon has synchronized with the ZumCoin network.

daemon.on('synced', () => {
  // do something
})

Event - syncing

This event is emitted when the daemon is syncing. It gives the current status of the sync.

daemon.on('syncing', (height, networkHeight, percent) => {
  // do something
})

Event - topblock

This event is emitted when the daemon detects a new top block on the network. It will be the next block found.

daemon.on('topblock', (height) => {
  // do something
})

ZumCoind RPC API Interface

As we can actually run this wrapper inside another nodeJS project, we expose all of the ZumCoind RPC API commands via the daemon.api property. Each of the below methods are Javascript Promises. For safety sake, always handle your promise catches as we do use them properly.

Methods noted having options have parameters that may be optional or required as documented.

daemon.api.getBlocks(options)

Returns information on the last 30 blocks before height (inclusive).

options.height The height of the blockchain to start at - required

Example Data

[
  {
    "cumul_size": 22041,
    "difficulty": 285124963,
    "hash": "62f0058453292af5e1aa070f8526f7642ab6974c6af2c17088c21b31679c813d",
    "height": 500000,
    "timestamp": 1527834137,
    "tx_count": 4
  },
  {
    "cumul_size": 384,
    "difficulty": 258237161,
    "hash": "74a45602da61b8b8ff565b1c81c854416046a23ca53f4416684ffaa60bc50796",
    "height": 499999,
    "timestamp": 1527834031,
    "tx_count": 1
  },
  {
    "cumul_size": 418,
    "difficulty": 256087255,
    "hash": "ed628ff13eacd5b99c5d7bcb3aeb29ef8fc61dbb21d48b65e0cdaf5ab21211c1",
    "height": 499998,
    "timestamp": 1527834020,
    "tx_count": 1
  }
]

daemon.api.getBlock(options)

Returns information on a single block

options.hash Block hash of the block you wish to retrieve - required

Sample Data

{
  "alreadyGeneratedCoins": "1484230931125",
  "alreadyGeneratedTransactions": 974921,
  "baseReward": 2935998,
  "blockSize": 48846,
  "depth": 0,
  "difficulty": 358164537,
  "effectiveSizeMedian": 100000,
  "hash": "f11580d74134ac34673c74f8da458080aacbe1eccea05b197e9d10bde05139f5",
  "height": 501854,
  "major_version": 4,
  "minor_version": 0,
  "nonce": 214748383,
  "orphan_status": false,
  "penalty": 0,
  "prev_hash": "674046ea53a8673c630bd34655c4723199e69fdcfd518503f4c714e16a7121b5",
  "reward": 2936608,
  "sizeMedian": 231,
  "timestamp": 1527891820,
  "totalFeeAmount": 610,
  "transactions": [
    {
      "amount_out": 2936608,
      "fee": 0,
      "hash": "61b29d7a3fe931928388f14cffb5e705a68db219e1df6b4e15aee39d1c2a16e8",
      "size": 266
    },
    {
      "amount_out": 2005890,
      "fee": 110,
      "hash": "8096a55ccd0d4a736b3176836429905f349c3de53dd4e92d34f4a2db7613dc4b",
      "size": 2288
    },
    {
      "amount_out": 3999900,
      "fee": 100,
      "hash": "304a068cbe87cd02b48f80f8831197174b133870d0c118d1fe65d07a33331c4e",
      "size": 2691
    },
    {
      "amount_out": 7862058,
      "fee": 100,
      "hash": "29c0d6708e8148eec6e02173b3bab0093768e5f486f553939495a47f883b4445",
      "size": 9638
    },
    {
      "amount_out": 6951392,
      "fee": 100,
      "hash": "fe661f11a0ba9838610c147f70813c17755ab608c7b033f6432c0b434671182c",
      "size": 10004
    },
    {
      "amount_out": 6800150,
      "fee": 100,
      "hash": "4b0366f79ec341cf60d5ef8c9dd8e65974dacb1be1d30dc0bf11d2d9d8240b46",
      "size": 11493
    },
    {
      "amount_out": 7260417,
      "fee": 100,
      "hash": "066b86268b7bb2f780ed76f452d1e6f7213dc6cae273b71fbd4ba378befaed00",
      "size": 12155
    }
  ],
  "transactionsCumulativeSize": 48535
}

daemon.api.getTransaction(options)

Gets information on the single transaction.

options.hash The transaction hash - required

Sample Data

{
  "block": {
    "cumul_size": 22041,
    "difficulty": 103205633,
    "hash": "62f0058453292af5e1aa070f8526f7642ab6974c6af2c17088c21b31679c813d",
    "height": 500000,
    "timestamp": 1527834137,
    "tx_count": 4
  },
  "status": "OK",
  "tx": {
    "extra": "019e430ecdd501714900c71cb45fd49b4fa77ebd4a68d967cc2419ccd4e72378e3020800000000956710b6",
    "unlock_time": 500040,
    "version": 1,
    "vin": [
      {
        "type": "ff",
        "value": {
          "height": 500000
        }
      }
    ],
    "vout": [
      {
        "amount": 80,
        "target": {
          "data": {
            "key": "5ce69a87940df7ae8443261ff610861d2e4207a7556ef1aa35878c0a5e7e382d"
          },
          "type": "02"
        }
      },
      {
        "amount": 200,
        "target": {
          "data": {
            "key": "7c7f316befaac16ba3782a2ce489e7c0f16c2b733ac0eaa0a72a12ee637822e9"
          },
          "type": "02"
        }
      },
      {
        "amount": 6000,
        "target": {
          "data": {
            "key": "defcb7eb6537bf0a63368ed464df10197e67d7ea8f080e885911cf9ea71abb62"
          },
          "type": "02"
        }
      },
      {
        "amount": 30000,
        "target": {
          "data": {
            "key": "9693e864dba53f308d0b59623c608b6fe16bbdc7cdc75be94f78582d547b46a4"
          },
          "type": "02"
        }
      },
      {
        "amount": 900000,
        "target": {
          "data": {
            "key": "b739e9fbaa3ee976a9ed8ad93a2731ee191c384cf136929e737786573fcd3e96"
          },
          "type": "02"
        }
      },
      {
        "amount": 2000000,
        "target": {
          "data": {
            "key": "5621667d44e7ffb87e5010a5984c188f58a799efb01569e8e42fa2415bb7d14a"
          },
          "type": "02"
        }
      }
    ]
  },
  "txDetails": {
    "amount_out": 2936280,
    "fee": 0,
    "hash": "702ad5bd04b9eff14b080d508f69a320da1909e989d6c163c18f80ae7a5ab832",
    "mixin": 0,
    "paymentId": "",
    "size": 266
  }
}

daemon.api.getTransactionPool()

Gets the list of transaction hashs in the mempool.

Sample Data

[
  {
    "amount_out": 1660000,
    "fee": 0,
    "hash": "721ae50994d5446d5683ca79d6fa97dce321a39e88e1df70ae433dc67573841b",
    "size": 13046
  },
  {
    "amount_out": 325000,
    "fee": 0,
    "hash": "fc88004d9cd012c0341506f13003da015efec940cffca0baeff0a381c7846203",
    "size": 28038
  },
  {
    "amount_out": 4040000,
    "fee": 0,
    "hash": "de63292050c73db4bb74637910ceab2aef6b9a0b611d0d93e7a757f9c53f975a",
    "size": 28058
  },
  {
    "amount_out": 10200000,
    "fee": 0,
    "hash": "edcd17184bd0c953be009da6b555e90a7cd5fc596f5f560332382995be7b55a7",
    "size": 28091
  },
  {
    "amount_out": 3380000,
    "fee": 0,
    "hash": "e1846775508a750a2f027db46972114e86866d27d304c9178867ae4616b3723c",
    "size": 28092
  },
  {
    "amount_out": 3960000,
    "fee": 0,
    "hash": "015646a75a5279050b5f02df6d5ff9814860fabc8b093818995a4fb6a33e45d8",
    "size": 28096
  },
  {
    "amount_out": 3860000,
    "fee": 0,
    "hash": "5e2f8bcc8c6c9a74e8ce33a66213711b418633eceeefce50042aecb8544676ba",
    "size": 28097
  }
]

daemon.api.getBlockCount()

Gets the current block count

Sample Data

502322

daemon.api.getBlockHash(options)

Gets a block hash by height.

options.height The height of the block - required

Sample Data

74a45602da61b8b8ff565b1c81c854416046a23ca53f4416684ffaa60bc50796

daemon.api.getBlockTemplate(options)

options.reserveSize Reserve size - required options.walletAddress Public Wallet Address - required

Sample Data

{
  "blocktemplate_blob": "0400...0581",
  "difficulty": 194635827,
  "height": 502335,
  "reserved_offset": 412,
  "status": "OK"
}

daemon.api.submitBlock(options)

options.blockBlob The block blob data - required

Sample Data

{
  "status": "OK"
}

daemon.api.getLastBlockHeader()

Sample Data

{
  "block_header": {
    "block_size": 419,
    "depth": 0,
    "difficulty": 200671816,
    "hash": "7d6db7b77232d41c19d898e81c85ecf08c4e8dfa3434f975a319f6261a695739",
    "height": 502345,
    "major_version": 4,
    "minor_version": 0,
    "nonce": 130876,
    "num_txes": 1,
    "orphan_status": false,
    "prev_hash": "5af657331edff98791720c23aacf72e8b6247ddba2a5c42c93984a46946abd14",
    "reward": 2935955,
    "timestamp": 1527907348
  },
  "status": "OK"
}

daemon.api.getBlockHeaderByHash(options)

options.hash Block hash - required

Sample Data

{
  "block_header": {
    "block_size": 419,
    "depth": 2,
    "difficulty": 200671816,
    "hash": "7d6db7b77232d41c19d898e81c85ecf08c4e8dfa3434f975a319f6261a695739",
    "height": 502345,
    "major_version": 4,
    "minor_version": 0,
    "nonce": 130876,
    "num_txes": 1,
    "orphan_status": false,
    "prev_hash": "5af657331edff98791720c23aacf72e8b6247ddba2a5c42c93984a46946abd14",
    "reward": 2935955,
    "timestamp": 1527907348
  },
  "status": "OK"
}

daemon.api.getBlockHeaderByHeight(options)

options.height Block height - required

Sample Data

{
  "block_header": {
    "block_size": 419,
    "depth": 2,
    "difficulty": 200671816,
    "hash": "7d6db7b77232d41c19d898e81c85ecf08c4e8dfa3434f975a319f6261a695739",
    "height": 502345,
    "major_version": 4,
    "minor_version": 0,
    "nonce": 130876,
    "num_txes": 1,
    "orphan_status": false,
    "prev_hash": "5af657331edff98791720c23aacf72e8b6247ddba2a5c42c93984a46946abd14",
    "reward": 2935955,
    "timestamp": 1527907348
  },
  "status": "OK"
}

daemon.api.getCurrencyId()

Sample Data

7fb97df81221dd1366051b2d0bc7f49c66c22ac4431d879c895b06d66ef66f4c

daemon.api.height()

Sample Data

{
  "height": 502354,
  "network_height": 502354,
  "status": "OK"
}

daemon.api.info()

Sample Data

{
  "alt_blocks_count": 14,
  "difficulty": 289121015,
  "grey_peerlist_size": 4997,
  "hashrate": 9637367,
  "height": 502354,
  "incoming_connections_count": 12,
  "last_known_block_index": 502352,
  "network_height": 502354,
  "outgoing_connections_count": 8,
  "status": "OK",
  "synced": true,
  "tx_count": 473486,
  "tx_pool_size": 1,
  "version": "0.5.0",
  "white_peerlist_size": 1000
}

daemon.api.fee()

Sample Data

{
  "address": "Zum1yiVt3UDGr5XwUpvdeNbG5c7ufBLPR85hY43gGXMqcuM2y4ZNBQdEBAj76BqdtjHuCnbDRZWdoQkAbs5MMCbubsyHS5T787E27NRnfaGLvxDuE1SfQt2zbvfEiTNJtFcBNZwUAAQYL1oxejK1c8PaCTCa61he99a31So9KNaQ4kGkKjjstwhyM2FqdwUyU",
  "amount": 5000,
  "status": "OK"
}

daemon.api.getTransactions()

Sample Data

{
  "missed_tx": [],
  "status": "OK",
  "txs_as_hex": []
}

daemon.api.peers()

Sample Data

{
  "peers": [
    "174.21.179.198:17936",
    "94.23.49.75:17936",
    "...",
    "80.14.183.25:17936",
    "71.193.1.94:17936"
  ],
  "status": "OK"
}

daemon.api.sendRawTransaction()

Note: This method is not implemented.

WebSocket Connections

A WebSocket socket.io server is initialized if enableWebSocket is true in the initialization of the module. The server is created on the rpcBindPort specified + 1.

Some events require that the socket is authenticated via a auth event.

If the nonce column is Yes you may send a nonce in the payload in addition to the options defined.

Client Initiated Events

|Event|JSON Payload|Nonce Honored|Payload| |---|---|---|---| |auth|No|No|string sha256 hash of password| |getBlocks|Yes|Yes|See daemon.api.getBlocks(options)| |getBlock|Yes|Yes|See daemon.api.getBlocks(options)| |getTransaction|Yes|Yes|See daemon.api.getTransaction(options)| |getTransactionPool|Yes|Yes|See daemon.api.getTransactionPool()| |getBlockCount|Yes|Yes|See daemon.api.getBlockCount()| |getBlockHash|Yes|Yes|See daemon.api.getBlockHash(options)| |getBlockTemplate|Yes|Yes|See daemon.api.getBlockTemplate(options)| |submitBlock|Yes|Yes|See daemon.api.submitBlock(options)| |getLastBlockHeader|Yes|Yes|See daemon.api.getLastBlockHeader()| |getBlockHeaderByHash|Yes|Yes|See daemon.api.getBlockHeaderByHash(options)| |getBlockHeaderByHeight|Yes|Yes|See daemon.api.getBlockHeaderByHeight(options)| |getCurrencyId|Yes|Yes|See daemon.api.getCurrencyId()| |height|Yes|Yes|See daemon.api.getHeight()| |info|Yes|Yes|See daemon.api.getInfo()| |fee|Yes|Yes|See daemon.api.fee()| |getTransactions|Yes|Yes|See daemon.api.getTransactions()| |peers|Yes|Yes|See daemon.api.getPeers()| |sendRawTransaction|Yes|Yes|See daemon.api.sendRawTransaction()|

Server Initiated Events

|Event|Authentication Required|Payload| |---|---|---| |block|No|See Event - block| |stopped|Yes|See Event - stopped| |data|Yes|See Event - data| |desync|Yes|See Event - desync| |down|Yes|See Event - down| |error|Yes|See Event - error| |info|Yes|See Event - info| |ready|Yes|See Event - ready| |start|Yes|See Event - start| |started|Yes|See Event - started| |synced|Yes|See Event - synced| |syncing|Yes|See Event - syncing| |topblock|No|See Event - topblock| |warning|Yes|*See Event - warning|

Server Responses

All responses except for auth return data in the same format.

{
  "nonce": 123456,
  "data": <payload>
}

|Event|Nonced|Payload| |---|---|---| |auth|No|boolean Responds to a client initiated auth event. If true the password was correct. If false the password was incorrect.| |getBlocks|Yes|See daemon.api.getBlocks(options)| |getBlock|Yes|See daemon.api.getBlocks(options)| |getTransaction|Yes|See daemon.api.getTransaction(options)| |getTransactionPool|Yes|See daemon.api.getTransactionPool()| |getBlockCount|Yes|See daemon.api.getBlockCount()| |getBlockHash|Yes|See daemon.api.getBlockHash(options)| |getBlockTemplate|Yes|See daemon.api.getBlockTemplate(options)| |submitBlock|Yes|See daemon.api.submitBlock(options)| |getLastBlockHeader|Yes|See daemon.api.getLastBlockHeader()| |getBlockHeaderByHash|Yes|See daemon.api.getBlockHeaderByHash(options)| |getBlockHeaderByHeight|Yes|See daemon.api.getBlockHeaderByHeight(options)| |getCurrencyId|Yes|See daemon.api.getCurrencyId()| |height|Yes|See daemon.api.height()| |info|Yes|See daemon.api.info()| |fee|Yes|See daemon.api.fee()| |getTransactions|Yes|See daemon.api.getTransactions()| |peers|Yes|See daemon.api.peers()| |sendRawTransaction|Yes|See daemon.api.sendRawTransaction()|

License

Copyright (c) 2019, The ZumCoin Developers

Please see the included LICENSE file for more information.