Before diving into the details of how Starport helps you scaffold the basics for your application blockchain make sure to understand the main concepts presented in the following sections:
You can follow a hands-on exercise for Starport in the sections that follow this introduction.
The Cosmos SDK provides the building blocks for a complete Tendermint blockchain, which implements the Inter-Blockchain Communication Protocol (IBC). The BaseApp of the Cosmos SDK assembles these building blocks and provides a fully-running blockchain. All there is left to do for the specific blockchain application is to create specific modules and integrate them with BaseApp to make the application your own.
Starport assists with scaffolding modules and integrating them with BaseApp. Starport is a command-line tool that writes code files and updates them when instructed to do so. If you come from an on Rails world, the concept will look familiar to you.
On top of that Starport will handle some compilation, run a local blockchain node, and help you with other tasks.
Want to dedicate some time to dive deeper into installing Starport? Have a look at how to install Starport in the Starport Developer Guide (opens new window).
To install Starport at the command line:
You can verify the version of Starport you have once it is installed:
This entire exercise was built using the Starport version noted above. Using a newer version could work, but you might run into compatibility issues if you clone any code made with this version of Starport and then try to continue the project with your version of Starport.
To install this specific version of Starport, use:
If you'd like to upgrade an existing project to the latest version of Starport, you can follow the Starport migration documentation (opens new window).
You can also just type
starport to see the offered commands:
# Your chain
Start by scaffolding a basic chain called
checkers that you will place under the GitHub path
The scaffolding takes some time as it generates the source code for a fully functional ready-to-use blockchain. Starport creates a folder named
checkers and scaffolds the chain inside it.
checkers folder contains several generated files and directories that make up the structure of a Cosmos SDK blockchain. It contains the following folders:
app: a folder for the application.
cmd: a folder for the command-line interface commands.
proto: a folder for the Protobuf objects definitions.
vue: a folder for the UI.
x: a folder for all your own modules, in particular
If you look at the code that Starport generates, for instance in
./x/checkers/module.go, you will often see comments like the following:
Caution: Do not remove or replace any such lines in your code as they provide markers for Starport on where to add further code when instructed to do so. For the same reason, do not rename or move any file that contains such a line.
Go to the
checkers folder and run:
starport chain serve command downloads dependencies and compiles the source code into a binary called
checkersd. The command:
- Installs all dependencies.
- Builds Protobuf files.
- Compiles the application.
- Initializes the node with a single validator.
- Adds accounts.
After this command completes, you have a local testnet with a running node. What about the added accounts? Take a look at:
In this file, you can set the accounts, the accounts' starting balances, and the validator. You can also let Starport generate a client and a faucet. The faucet gives away five
token and 100,000
stake tokens belonging to Bob each time it is called.
You can observe the endpoints of the blockchain in the output of the
starport chain serve command:
Starport can detect any change to the source code. When it does, it immediately rebuilds the binaries before restarting the blockchain and keeping the state.
# Your GUI
Now boot up the frontend created by Starport by using the commands provided in the
readme.md file of the
checkers folder. For this you let the chain run in its own process and open a new terminal window in your
checkers folder. In this terminal execute:
Navigate to localhost:8080 (opens new window). On the client side no wallets have been created or imported yet. Load Alice's wallet in the GUI to have some tokens. You will need to use the mnemonic for Alice which you can find in the output of the
starport chain serve command. Copy and paste it to import a wallet.
Now you should see the balance of Alice's account and can act on her behalf.
Select Custom Type in the sidebar to see custom types. There are no custom types yet, this page is empty for now.
It is good practice to make a Git commit before you create a new
message. In fact, it is generally recommended to make a Git commit before running any
starport scaffold command. A Git commit protects the work you have done so far and makes it easier to see what the
scaffold command added. It also makes it easy to just revert all changes if you are unsatisfied and want to run a different
# Your first message
With your Git commit tucked away, now create a simple
starport scaffold message command accepts a message name, here
createPost, as the first argument, and a list of fields for the message, here
body, which are
strings unless mentioned otherwise.
A message is scaffolded in a module with a name that matches the name of the project by default. It is named
checkers in this case. Or you could have used
--module checkers. Learn more about your options with:
You can see a list of files that were created or modified by the
scaffold message command in the Terminal output:
modify was made possible thanks to the lines like
// this line is used by starport scaffolding # 1 that you did not remove. So where is everything? You can find the root definition of your new message in:
Starport also wired a new command into your chain's CLI in:
Starport scaffolded GUI elements relating to your message with a Vue.js frontend framework. You can, for instance, start with this function in:
# Next up
You just created a fully working Cosmos SDK chain, one that forms the basis of the following exercise.
You can remove the
MsgCreatePost message as it is not part of the guided exercise in the next sections. You can clean it all by running: