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    Cudos Blast

    Cudos Blast is a Node.js CLI (command line interface) tool for working with the Cudos blockchain. You can scaffold, compile and test your Rust smart contracts. JavaScript and Rust testing is supported. Utilizing blast.config.js it provides a possibility for deploying and interacting with them on a specified network (local, test or public). By using this tool you can also spin up a local Cudos node and interact with it.

    Table of Contents


    Make sure you have Node.js installed. Docker is also required.

    Prerequisite Minimum version Recommended version
    Node.js 14.15.0 16.10.0
    npm 6.9.0 7.24.0
    Docker engine 19.03.13 20.10.12
    Docker compose 1.27.4 1.29.2

    For Windows users we recommend using Windows Subsystem for Linux (WSL). To avoid permission issues with WSL, you may have to change npm default directory.

    Cudos Blast can be used through a local installation in your project or by installing it globally.

    Local Installation

    Create an npm project by going to an empty folder, then run npm init and follow the instructions. Once your project is ready, run npm install cudos-blast. To use your local installation of Cudos Blast, use npx blast.

    Global Installation

    You can let npm completely manage Cudos Blast package just by using npx cudos-blast to directly run commands. That way you will always be using the latest version of Cudos Blast so it is possible to have future compatibility issues. We recommend running

    npm install cudos-blast -g

    to install globally and using Cudos Blast by blast as all the examples in this guide do.

    Help and version

    Run --help or help on any blast command to show all available subcommands, parameters and additional information.

    blast --help
    blast help
    blast node --help
    blast node start help

    You can display cudos-blast version number using --version.

    blast --version

    Initializing a project

    To scaffold a sample project navigate to empty directory (or your npm project for local cudos-blast installation) and run

    blast init

    You can also specify the full directory of the project using optional parameter --dir or -d

    blast init --dir /Your/Location/Here

    The project is now ready to work with the Cudos blockchain. It contains sample smart contracts and scripts to deploy or interact. The new project's npm dependencies are automatically installed.

    Make sure to initialize a new project in a directory other than the local repository folder, or else cudos-blast will break and the repository have to be cloned again.
    Also, all blast commands are designed to be executed from the project root directory.

    Compiling smart contracts

    To compile all smart contracts run

    blast compile

    The contracts have to be in {project_root}/contracts/ folder. Cudos Blast comes with sample contracts you can use. All contracts are compiled in alphabetical order and as a Rust workspace. If you want to add more folders to compile, all you have to do is edit the base {project_root}/Cargo.toml file and add your folder under members. The compilation is done using rust-optimizer and the artifacts in {project_root}/artifacts/ folder are optimized for deployment.

    Running Rust tests

    Rust tests are organized by the Rust convention for writing tests. You can check them in their corresponding contracts in {project_root}/contracts/{contract_name}/. To run smart contracts' Rust tests:

    blast rusttest

    To run the Rust tests without printing cargo log messages use --quiet or -q

    blast rusttest -q

    Testing contracts with JavaScript

    Cudos Blast uses Jest framework for testing. Test files must be in {project_root}/tests/ folder. You can use the provided sample test as a template or make one or more tests of your own. You can run the default local node in order to deploy or interact with the smart contracts in your tests. To connect to a non-local Cudos node such as testnet or your own node, follow these instructions.

    describe('alpha contract', () => {
      const MSG_INIT = { count: 13 }
      const MSG_INCREMENT = { increment: {} }
      const MSG_RESET = { reset: { count: 1 } }
      const QUERY_GET_COUNT = { get_count: {} }
      let alice, bob, contract
      // deploying alpha contract once before test cases
      beforeAll(async () => {
        // 'bre' is available in global context
        [alice, bob] = await bre.getSigners()
        contract = await bre.getContractFactory('alpha')
        await contract.deploy(MSG_INIT, 'alpha', { signer: bob })
      // positive test case
      test('increment count', async () => {
        await contract.execute(MSG_INCREMENT, alice)
        return expect(contract.query(QUERY_GET_COUNT))
          .resolves.toEqual({ count: 14 })
      // ...
      // negative test case
      test('reset count from user throws unauthorized', () => {
        return expect(contract.execute(MSG_RESET, alice))

    Run all test files with

    blast test
    blast test -n testnet

    You can also run the tests with disabled console logging and show only essential test result information. To do this use --silent or -s

    blast test --silent

    Interacting with a Cudos node

    You can interact with a local Cudos node with blast node command.

    Starting a local node

    To start a fresh local Cudos node run

    blast node start

    or you can show the node logging output in current terminal window. To do this use --log or -l.

    blast node start -l

    To see how to manage local node accounts go here.

    Stopping a running local node

    To stop a running node run

    blast node stop

    Checking node status

    To check whether any Cudos node is online or offline run

    blast node status
    blast node status -n testnet

    More information about connecting to a non-local Cudos node here.

    Deploying smart contracts, interacting with them and running custom script files

    You can use the supplied {project_root}/scripts/deploy.js to deploy a sample smart contract.

    async function main () {
      // functions such as 'getSigners' and 'getContractFactory' are available in global context
      const [alice, bob] = await bre.getSigners()
      // get contract object of 'alpha' contract in 'contracts/alpha'
      const contract = await bre.getContractFactory('alpha')
      // define instantiate message for the contract
      // in this message you can set called function and its parameters
      const MSG_INIT = { count: 13 }
      // deploying the contract with bob as a signer (default signer would be alice)
      const deploy = await contract.deploy(MSG_INIT, 'alpha', { signer: bob })
      // get useful info such as contractAddress from deploy transaction
      const contractAddress = deploy.instantiateTx.contractAddress
      // printing contract address so it can be copied and used in other scripts such as interact.js
      console.log(`Contract deployed at: ${contractAddress}`)
    // ...

    Deploy the contract by running the script:

    blast run scripts/deploy.js

    When the contract is deployed, its address will be printed. Then you can edit {project_root}/scripts/interact.js with the new address

    async function main() {
      const [alice, bob] = await bre.getSigners()
      // replace the address with the new one from your deployed smart contract
      const contract = await bre.getContractFromAddress('cudos1uul3yzm2lgskp3dxpj0zg558hppxk6pt8t00qe')
    // ...

    and run the script to interact with the deployed smart contract.

    blast run scripts/interact.js

    When running scripts through blast run the bre object in injected. It provides various useful functions to interact with cudos blockchain network. You can also require the cudos-blast library to access the same functions and enable your code editor's intellisense.

    const bre = require('cudos-blast')

    You are free to use these sample files as templates or create your own custom .js scripts. You can specify your own script file path.

    blast run scripts/myCustomScript.js
    blast run newFolder/anotherScripts/myCustomScript.js

    Available functions in global context

    Here is a list of functions you can use in your scripts.

    Function Descripton Sample usage
    async getSigners() If the local node is used: Returns an array of predefined accounts ({project_root}/local-accounts.json) including the auto generated additional accounts.
    For other networks: returns an array of user-defined private accounts from {project_root}/private-accounts.json.
    const [alice, bob] = await bre.getSigners()
    async getContractFactory(contractLabel) Returns an instance of a new contract by its label. const contract = await bre.getContractFactory('alpha')
    async getContractFromCodeId(codeId) Returns an instance of a contract whose code is uploaded but not instantiated. const contract = await bre.getContractFromCodeId(123)
    async getContractFromAddress(contractAddress) Returns an instance of an on-chain contract by its address. const contract = await bre.getContractFromAddress('cudos1uul3yzm2lgskp3dxpj0zg558hppxk6pt8t00qe')

    You can get an instance of a contract (e.g. with getContractFactory()). Here is the functionality such an instance of a contract can offer.

    Exposed functions of a contract instance

    Function Descripton Sample usage
    async uploadCode(options = { signer: null, gasLimit: null, gasMultiplier: null }) Uploads the contract's source code on the network so it can be optimally used to instantiate a contract multiple times with different initial state. const uploadTx = await contract.uploadCode()
    async instantiate(msg, label, options = { signer: null, funds: null, gasLimit: null, gasMultiplier: null }) Instantiates an uploaded contract with given initMsg and label. Can be used for undeployed as well as already deployed contracts. The new instantiated contract does not override the current contract object, and therefore it is designed to be accessed by its address. const instantiateTx = await contract.instantiate(MSG_INIT)
    async deploy(msg, label, options = { signer: null, funds: null }) Deploys the conttract with the given initMsg. You cannot use deploy on an instance ot contract whose code is already uploaded. const deployTxs = await contract.deploy(MSG_INIT, { label: 'myLabel' })
    async execute(msg, signer = null, options = { gasLimit: null, gasMultiplier: null }) Executes a transaction within the contract with the given message. const result = await contract.execute(MSG_INCREMENT, alice)
    async query(queryMsg, signer = null) Executes a query within the contract with the given message. const count = await contract.query(QUERY_GET_COUNT)
    getAddress() Returns the address of a deployed contract or null if undeployed. const address = contract.getAddress()
    getCodeId() Returns the code ID of an uploaded contract or null if unuploaded. const codeId = contract.getCodeId()
    getLabel() Returns the label of the contract or null if undeployed. const label = contract.getLabel()
    getCreator() Returns the address of the contract's creator or null if unuploaded. const label = contract.getCreator()
    Options object Descripton
    options = { signer } The signer to execute the functionality with. The default signer is the first one returned by getSigners().
    options = { funds } The amount of tokens to fund the newly created contract.
    options = { gasLimit } The maximum limit of gas a transaction can consume. Defaults to "auto".
    options = { gasMultiplier } gasLimit multiplier. Defaults to "auto" or 1.3. gasMultiplier is taken into consideration only when auto gasLimit is used.

    Additional options

    • You can run your scripts on a different node. More information here
    • You can set a custom address prefix under addressPrefix in blast.config.js. The default prefix is cudos
    blast run scripts/myCustomScript.js -n testnet
    • You can automatically fund smart contracts with tokens in your scripts
    async function main () {
      const [alice, bob] = await getSigners()
      const contract = await getContractFactory('alpha')
      const MSG_INIT = { count: 13 }
      const deploy = await contract.deploy(MSG_INIT, 'alpha', { signer: bob, fund: 123 })
      // ...
    • Gas fees are calculated and applied per transaction. Note that deploy() function submits two separate transactions (upload code + instantiate), and therefore auto gasLimit and gasMultiplier are used.
    • You can specify gas price from blast.config.js. It is used in format <amount>acudos

    Creating a custom task

    Cudos Blast allows the creation of custom tasks that can easily run commonly used operations or help manage your workflow. This guide shows you how to create a sample task to print a parameter from the CLI.

    Let's add the following line in our blast.config.js outside of the scope of module.exports:

    task("print", "Prints a custom parameter").setAction(async () => {});

    It is a good practice to split your code into several files and require them from the config file for more complex tasks.

    After adding it, you should be able to see the task and its description in blast --help.

    Usage: blast <command> [arguments] [command options]
      blast init                  Create a sample project
      blast compile               Compile the smart contracts in the workspace in
                                  alphabetical order
      blast test                  Run the JavaScript tests
      blast rusttest              Run smart contracts rust tests
      blast node                  Manage a local CUDOS node
      blast run <scriptFilePath>  Run a single script
      blast keys                  Manage node accounts (keys)
      blast print                 Prints a custom parameter
      --version  Show version number                                       [boolean]
      --help     Show help                                                 [boolean]

    now let's add a param to our task

    task("print", "Prints a custom parameter")
      .addParam("param", "Our custom parameter")
      .setAction(async (argv) => {
        console.log(`Printing our param... ${argv.param}`)
    module.exports.config = {
    // ...

    Now we can simply invoke it by running:

    blast print --param "important thing to print"

    You can add as many parameteres with .addParam() as you need.

    You should know that every task must end with .setAction() so it can take it's place.


    You can connect to the default local node as well as a public one or you can use your own Cudos node. To do that, add a {custom_name}: {node_url} to networks field in blast.config.js, then call the run, test or node status command with --network or -n followed by {custom_name}. If no network is passed, blast commands connect to the default local node.
    Here are Cudos nodes you can use to connect to Cudos network:


    Chain ID URL
    cudos-network http://localhost:26657


    Chain ID URL


    Chain ID URL

    Managing accounts

    By default local Cudos node starts with 10 predefined accounts funded with acudos. You can set how many additional random accounts to load when starting a local node in blast.config.js under additionalAccounts. If any additional accounts are added, customAccountBalances field must be set for the amount of tokens that these accounts will be funded with. Predefined and additionally generated accounts are written in {project_root}/local-accounts.json. Another way to manage custom accounts is through blast keys command.
    You can put your private accounts in {project_root}/private-accounts.json. Initializing a new project automatically adds this file to .gitignore. Make sure you keep private-accounts.json in .gitignore in order to prevent accidentally committing and exposing your private accounts.. The private-accounts.json file is mainly meant to have existing accounts in other networks (testnet, mainnet, etc). If you also want to have these accounts in your local environment, make sure you add them to your local node keyring.

    Listing local node accounts

    To list all accounts in the local node key storage run

    blast keys ls

    Adding a new local node account

    To add a new account named myAccount1 to the local node key storage run

    blast keys add myAccount1

    After adding the new account, it is automatically funded with acudos tokens from the default local node faucet.

    Removing an existing local node account

    To remove an account from the node key storage run

    blast keys rm myAccount1

    You can skip the delete confirmation with --force or -f

    blast keys rm myAccount1 -f

    Funding an existing local node account

    You can fund an account with additional tokens. To specify tokens amount use --tokens or -t.

    blast keys fund myAccount1 --tokens 1000000

    The tokens are funded from the default local node faucet in acudos.


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