Exonum Bootstrap Library

Main goal to shrink amount of code to bootstap your own blockchain on Exonum Framework.

Make it:

• Shorter
• Simplier
• Readable

Features

Records define

Exonum Bootstrap provides handy proc-macros to define encoded struct (exonum blockchain record):

// derive macros will create Wallet encoding structure
#[derive(exonum_record)]
struct __Wallet {
  // mark field as primary key (will be index of data)
  #[key]
  pub_key: &'static PublicKey,

  // define custom size
  #[size = "8"]           
  name: &'static str,

  balance: u64
}

Transactions define

Another proc-macros allows to define it same way transactions:

// macros will create TxCreateWallet structure as encoded message
#[derive(exonum_message)]
struct __CreateWallet {
  #[key]
  pub_key: &'static PublicKey,

  #[size = "8"]
  name: &'static str,
}

Also it will create verification of signature inside verify function from Transaction trait. To create custom verify and\or execute logic please implement TransactionMethods trait:

impl TransactionMethods for TxCreateWallet {
  fn verify(&self) -> bool { 
    self.name().len() > 3
  }

  fn execute(&self, view: &mut Fork) {
    let mut schema = WalletSchema { view };
    if schema.get(self.pub_key()).is_none() {
      let wallet = Wallet::new(self.pub_key(), self.name(), 0);
      schema.index().put(self.pub_key(), wallet)
    }
  }
}

Schema creation

Based on defined records Exonum Bootstrap will create coresponding schemas (like WalletSchema for __Wallet example).

Base implementation of schema contains two function: index and get. Function based on #[key] signed field of struct and use it as a key value in MapIndex

Service bootstrapping

Exonum Bootstrap could to implement basic service and api for you based on declarative definition:

#[derive(exonum_service)]
#[id = "1"]
struct __Currency {
  #[record = "1"]
  wallet: __Wallet,

  // api endpoint for tx (TxCreateWallet)
  #[input = "1"]
  create_wallet: __CreateWallet,

  // api endpoint for tx (TxTransfer)
  #[input = "2"]
  transfer: __Transfer
}

In addition to receiving transactions, the api provides a service scheme:

{
  "id": 1,
  "inputs": [
    {
      "id": 1,
      "name": "TxCreateWallet",
      "request": [
        {
          "from": 0,
          "modificators": [
            {
              "name": "key",
              "value": null
            }
          ],
          "name": "pub_key",
          "size": 32,
          "to": 32,
          "ty": "& PublicKey"
        },
        {
          "from": 32,
          "modificators": null,
          "name": "name",
          "size": 8,
          "to": 40,
          "ty": "& str"
        }
      ],
      "response": null,
      "size": 40
    },
    ...
  ],
  "name": "CurrencyService",
  "outputs": null,
  "records": [
    {
      "id": 1,
      "name": "Wallet",
      "fields": [
        {
          "from": 0,
          "modificators": [
            {
              "name": "key",
              "value": null
            }
          ],
          "name": "pub_key",
          "size": 32,
          "to": 32,
          "ty": "& PublicKey"
        },
        ...
      ]
    }
  ]
}

Roadmap

Future plans to improvement functionality of Exonum Bootstrap pretty opaque and relates to my own need.. but if you wish something special, please, tell me over Issue.

Future plans:

• Outputs (read data from blockchain)
• Definition of a transactions responses
• Configuration of API endpoints
• Cover code with tests...
• Detailed docs