Building a Simple Clicker Game on Osmosis Testnet
This tutorial introduces you to interact with All That Node product to deploy Wasm smart contract to Osmosis Testnet (osmo-test-4), and to create a simple clicker game. You might be able to test the things that we are going to build on the following deployed site.
A full screenshot of Clicker Game (1)
A full screenshot of Clicker Game (2)
A full screenshot of Clicker Game (3)

Prerequisites

  • Sign up to All That Node (ATN) and secure your account
  • Download your own IDE - recommend Visual Studio Code​
  • Install Git on your computer
  • install [rustup](<https://rustup.rs/>)

Step 0: Setting up your environments

Set up Rust

Rust is the main programming language used for CosmWasm smart contracts. While WASM smart contracts can theoretically be written in any programming language, CosmWasm libraries and tooling work best with Rust.
Then run the following commands:
# 1. Set 'stable' as the default release channel:
​
rustup default stable
​
# 2. Add WASM as the compilation target:
​
rustup target add wasm32-unknown-unknown
​
# 3. Install the following packages to generate the contract:
​
cargo install cargo-generate --features vendored-openssl
cargo install cargo-run-script

Setup Osmosis Testnet

You can easily set up an Osmosis Testnet environment using the Osmosis Installer.
Run the following and choose option #2 (Client Node) and #2 (Testnet) in order.
curl -sL <https://get.osmosis.zone/install> > i.py && python3 i.py
Now you have successfully completed setting up an Osmosis client node in Testnet. In order to use osmosisd from the cli, either reload your terminal or refresh your profile with : ‘source ~/.profile’
​

Step 1: Faucet - Fund your Osmosis Account

Create Wallet

To begin, use the following command to generate a wallet for deployment.
osmosisd keys add wallet

Faucet using AllThatNode

using Osmosis faucet provided by ATN
To receive a free airdrop from Osmosis Testnet for testing purposes, you must first join Osmosis Discord. Link Meanwhile, utilizing the AllThatNode faucet makes your developer life much easier. Go to this link, enter your wallet address, and then click the Claim Your Tokens button. If you succeed, you may be able to obtain a transaction value.
The address of the wallet can be found through the osmosisd keys show -a wallet .
After requesting the faucet, use the command below to check the balance.
osmosisd query bank balances $(osmosisd keys show -a wallet)

Step 2: Compile a WebAssembly code

Clone repository

We'll use a straightforward counter contract code. The code is kept in the following repository.
Let's download the code with the following command:
cargo generate --git <https://github.com/DSRV-DevGuild/cw-template> --name my-first-contract
cd my-first-contract

Compile the wasm contract with stable toolchain

To deploy smart contracts, you must compile the code and make it an executable wasm binary file. We will compile the wasm contract with stable toolchain.
Compile using the command below:
# Set 'stable' as the default release channel:
rustup default stable
cargo wasm
After this compiles, it should produce a file in target/wasm32-unknown-unknown/release/my_first_contract.wasm. If you check the size of the file by using the ls -lh command, it shows around 1.8M. This is a release build, but not stripped of all unneeded code. To produce a much smaller version, you can run this which tells the compiler to strip all unused code out:
RUSTFLAGS='-C link-arg=-s' cargo wasm
This produces a file about 155K. To reduce gas costs, the binary size should be as small as possible. This will result in a less costly deployment, and lower fees on every interaction.
Also, if you don’t use compilation optimization, CosmWasm smart contract will not be deployed well due to exceeds limit error.

Optimized Compilation

You can do further optimization using rust-optimizer. rust-optimizer produces reproducible builds of CosmWasm smart contracts and does heavy optimization on the build size, using binary stripping and wasm-opt.
sudo docker run --rm -v "$(pwd)":/code \\
--mount type=volume,source="$(basename "$(pwd)")_cache",target=/code/target \\
--mount type=volume,source=registry_cache,target=/usr/local/cargo/registry \\
cosmwasm/rust-optimizer:0.12.6
Binary file will be at artifacts/my_first_contract.wasm folder and its size will be about 130K, which is more smaller than when only RUTFLAGS was used.

Step 3: Deploying a contract

Uploading a binary code

We require the RPC Endpoint address of the Osmosis Testnet in order to distribute the produced Wasm binary code, and we will utilize the reliable RPC endpoint given by All That Node (ATN).
To begin, navigate to the protocol's Osmosis page and choose New Project to establish the project that will get the API key.
Then you can see the projects on DASHBOARD that you have just created. To enter, click the Osmosis tab.
The API key and Testnet endpoint may then be verified as follows:
The $NODE variable contains the RPC endpoint address of the Osmosis Testnet for ease of deployment, and the $TXFLAG variable saves the following gas cost information: At this stage, you must copy and paste your API keys after the RPC endpoint location.
# bash
export NODE="--node <https://osmosis-testnet-rpc.allthatnode.com:26657/>{API KEY}"
export TXFLAG="${NODE} --chain-id osmo-test-4 --gas-prices 0.025uosmo --gas auto --gas-adjustment 1.3"
​
# zsh
export NODE=(--node <https://osmosis-testnet-rpc.allthatnode.com:26657/>{API KEY})
export TXFLAG=($NODE --chain-id osmo-test-4 --gas-prices 0.025uosmo --gas auto --gas-adjustment 1.3)
Now, post the code to the chain and use the following command to extract the CODE_ID: If the $CODE_ID value is logged normally, the upload was successful.
RES=$(osmosisd tx wasm store artifacts/my_first_contract.wasm --from wallet $TXFLAG -y --output json -b block)
​
CODE_ID=$(echo $RES | jq -r '.logs[0].events[-1].attributes[0].value')
echo $CODE_ID

Instantiate a new contract

In Osmosis Testnet, there are two ways to establish a contract instance: using osmosisd or using the GUI at https://osmosis-contracts.web.app/.
We're going to use osmosisd. To create an instance of a contract, set the initial state and run the instantiate command.
INIT='{"count":2}'
​
osmosisd tx wasm instantiate $CODE_ID "$INIT" \\
--from wallet --label "my first contract" $TXFLAG -y --no-admin
If the run was successful, you can check the deployment in Osmosis Explorer by searching for the output txhash value.
As a result of looking for transactions in Osmosis Explorer using hash values.
As a result of looking for transactions in Osmosis Explorer

Step 4: Execute a contract

Let us now test how well the contract we works without any hurdles. To begin, use the command below to obtain the address of the deployed contract.
CONTRACT=$(osmosisd query wasm list-contract-by-code $CODE_ID --output json | jq -r '.contracts[0]')
echo $CONTRACT

get_count

If you use the get count query to examine the value, you will see the original state {"data":{"count":2}} written in its entirety.
QUERY='{"get_count":{}}'
osmosisd query wasm contract-state smart $CONTRACT "$QUERY" --output json

increment

By running the get_count query again after the transaction below has failed, you can see that the value has increased by one from the previous count value.
TRY_INCREMENT='{"increment": {"count": 1}}'
osmosisd tx wasm execute $CONTRACT "$TRY_INCREMENT" --from wallet $TXFLAG -y

reset

After the transaction below is lost, check the value again through the get_count query to confirm that the count value has been reset to the specified value.
RESET='{"reset": {"count": 123}}'
osmosisd tx wasm execute $CONTRACT "$RESET" --from wallet $TXFLAG -y
​

Step 5: Communicate with frontend

Let's now look at how to communicate smart contracts placed on the Osmosis Testnet using CosmJS on the front end via a simple Clicker game.
The Clicker game is a basic game in which you click the CosmWasm symbol that appears on the screen for 15 seconds to get a score, and then you drop a transaction to the contract to record the score once the game is done.

Clone repository

You may play the game yourself by inspecting the completed code in the Step 3 branch of the repo below. Check this medium article (warning! in Korean) contains a full discussion of each implementation phase.
git clone https://github.com/DSRV-DevGuild/osmosis-clicker-game.git
cd cosmwasm-clicker-game
git checkout Step3
yarn install && yarn start

Connecting Keplr Wallet

The Keplr wallet is a wallet that supports the Cosmos ecosystem's interchain.
​Keplr Wallet Let's get started by installing the extension and making an account. By default, there is no test net on the linked network when you launch the Keplr wallet. To add a network that is not available by default, you must call a separate method at the frontend, pass the network's configuration value as an argument, and then request addition.
src/wallet/connect.js contains the code for adding a network to the Keplr wallet.
Check the keplr object to determine if the extension is installed, then connect to the Osmosis Testnet network using the window.keplr.experimentalSuggestChain function. You may now obtain network information after adding a network to your Keplr wallet.
The window.keplr.enable(chainId:string) function allows the website to request access to the wallet from Keplr for user authorization, and then collect the wallet's detailed information to generate the Client.
Finally, provide the wallet's information value to the parent component that ran the method connectWallet. When React.js delivers a value from a child component to a parent, the parent can drop the function to props, and the child can pass the value to a function factor. The getInfo method may be found in src/App.js.
// src/wallet/connect.js
import { SigningCosmWasmClient } from "@cosmjs/cosmwasm-stargate";
​
const connectWallet = async (chainInfo, { getInfo }) => {
// verify whether Keplr extension is installed on user's web browser
if (!window.getOfflineSigner || !window.keplr) {
alert("Please install keplr extension");
}
// Keplr wallet to be added on network
if (window.keplr.experimentalSuggestChain) {
try {
await window.keplr.experimentalSuggestChain(chainInfo);
} catch {
alert("Failed to suggest the chain");
}
} else {
alert("Please use the recent version of keplr extension");
}
// to request Keplr wallet to access into chainId
await window.keplr.enable(chainInfo.chainId);
// retreive OfflineSigner using chainId
const offlineSigner = window.getOfflineSigner(chainInfo.chainId);
// return address & public key pair array
const accounts = await offlineSigner.getAccounts();
// SigningCosmWasmClient object creating
const client = await SigningCosmWasmClient.connectWithSigner(
chainInfo.rpc,
offlineSigner
);
// getting a balance
const balance = await client.getBalance(
accounts[0].address,
chainInfo.stakeCurrency.coinMinimalDenom
);
// a function to pass values to parent component
getInfo(client, accounts[0].address, balance, chainInfo.chainId);
};
​
export default connectWallet;
ChainInfo that must be passed as a factor in window.keplr.experimentalSuggestChain can be found in src/wallet/network_info.js. This information is required to be communicated except that the Optional annotation has been processed, otherwise an error will occur.
// factory pattern
const chainInfo = (chainId, chainName, rpc, rest, coinDenom, coinMinimaldenom, coinDecimals, bech32) => {
return {
// chain Id
chainId: chainId,
// chain Name
chainName: chainName,
// chain RPC endpoint address
rpc: rpc,
// chain REST endpoint address
rest: rest,
// staking coin info
stakeCurrency: {
// denomination
coinDenom: coinDenom,
// uatom, uosmo
coinMinimalDenom: coinMinimaldenom,
// coin decimals
coinDecimals: coinDecimals,
},
// BIP44 paths
bip44: {
// BIP44 standard
// 'purpose' to fbe fixed as 44
// 'coinType' to use 118 for Cosmos Hub
coinType: 118,
},
// Bech32 information
bech32Config: {
bech32PrefixAccAddr: bech32,
bech32PrefixAccPub: bech32 + "pub",
bech32PrefixValAddr: bech32 + "valoper",
bech32PrefixValPub: bech32 + "valoperpub",
bech32PrefixConsAddr: bech32 + "valcons",
bech32PrefixConsPub: bech32 + "valconspub"
},
// all coins/tokens list
currencies: [{
// denomination
coinDenom: coinDenom,
// coin minimal denomination
coinMinimalDenom: coinMinimaldenom,
// coin decimals
coinDecimals: coinDecimals,
}],
// tokens to be paid as fee list
feeCurrencies: [{
// denomination
coinDenom: coinDenom,
// coin minimal denomination
coinMinimalDenom: coinMinimaldenom,
// coin decimals
coinDecimals: coinDecimals,
}],
// (Optional) Information used only to import addresses from ENS should match the coinType in BIP44 coinType: 118,
// Set (low: 0.01, average: 0.025, high: 0.04) to default unless otherwise specified
// Keplr does not yet support dynamic calculations based on on on-chain data
// It should be higher than the minimum gas price set by the RPC/REST endpoints and the validators in the chain.
gasPriceStep: {
low: 0.01,
average: 0.05,
high: 0.25
}
}
}
​
const networkInfo = {
"malaga-420" : chainInfo("malaga-420", "Malaga", "<https://rpc.malaga-420.cosmwasm.com:443>", "<https://api.malaga-420.cosmwasm.com>", "Málaga", "umlg", 6, "wasm"),
"osmo-test-4" : chainInfo("osmo-test-4", "Osmosis Testnet", "<https://testnet-rpc.osmosis.zone>", "<https://testnet-rest.osmosis.zone/>", "OSMO", "uosmo", 6, "osmo"),
"uni-3" : chainInfo("uni-3", "Juno Testnet", "<https://rpc.uni.junonetwork.io:443>", "<https://api.uni.junonetwork.io/>", "JUNOX", "ujunox", 6, "juno"),
"constantine-1" : chainInfo("constantine-1", "Archway Testnet", "<https://rpc.constantine-1.archway.tech:443>", "<https://api.constantine-1.archway.tech>", "CONST", "uconst", 6, "archway")
}
​
export default networkInfo;
src/App.js implements the Network Connection button on the main screen.
When you click the Osmosis Testnet button, it changes to DISCONNECT and a PLAY button is generated to take you to the gameplay screen, which displays the linked wallet's address and balance underneath.
App.js manages the client, address, balance, chainId state with useState, and when using the connectWallet function, give over the getInfo function along with the factor and store it with setState.
import "./App.css";
import { useState } from "react";
import { useNavigate } from "react-router-dom";
import networkInfo from "./wallet/network_info";
import connectWallet from "./wallet/connect";
​
function App() {
// the value from connectWallet
const [client, setClient] = useState();
const [address, setAddress] = useState();
const [balance, setBalance] = useState();
const [chainId, setChainId] = useState();
// the variable from visibility properties in PLAY button
const [visible, setVisible] = useState("hidden");
const navigate = useNavigate();
​
// tehe function to pass to connectWallet method
const getInfo = (client, address, balance, chainId) => {
setClient(client);
setAddress(address);
setBalance(balance);
setChainId(chainId);
setVisible("visible");
};
​
// initialize the information given by connectWallet method
const disconnect = (event) => {
setClient();
setChainId();
setAddress();
setBalance();
setVisible("hidden");
};
​
// Implement DISCONNECT and CONNECT buttons for each network based on chainId.
const renderBtn = () => {
return Object.keys(networkInfo).map((id) => {
if (chainId === id) {
return (
<button
type="button"
onClick={(event) => disconnect(event)}
className="disconnect-btn"
>
DISCONNECT
</button>
);
}
return (
<button
type="button"
onClick={(event) =>
connectWallet(event, networkInfo[id], { getInfo })
}
className="connect-btn"
>
{networkInfo[id].chainName}
</button>
);
});
};
​
// If the website is linked to a wallet, print out the address and balance.
const showWalletInfo = () => {
if (client) {
return (
<div className="wallet-info">
<p>{`address: ${address}`}</p>
<p>{`balance: ${balance.amount} ${balance.denom}`}</p>
</div>
);
}
};
​
// navigate to /play when clicked
const playGame = () => {
return (
<div className="menu">
<button
className="play-btn"
onClick={() => {
navigate("/play", {
state: {
address: address,
denom: balance.denom,
chainId: chainId
}
});
}}
style={{ visibility: visible }}
>
<span>PLAY</span>
</button>
{!client && <p>Choose your network and Connect wallet</p>}
{client && (
<p>Click as many CosmWasm Icon as you can within 15 seconds!</p>
)}
</div>
);
};
​
return (
<div className="App">
<header>
<div className="header-titles">
<img
alt="Cosmwasm Logo"
className="cosmwasm-logo"
src="/cosmwasm-logo.svg"
/>
<h1>Clicker Game</h1>
</div>
</header>
<div className="App-container">
<div className="App-menu-container">
{playGame()}
<div className="connect-wallet">{renderBtn()}</div>
</div>
{showWalletInfo()}
</div>
</div>
);
}
​
export default App;

Communicate with a deployed contract

You can find the address of the contract we published to Osmosis Testnet previously in the src/contract/address.js file.
const contractAddress = {
"malaga-420":
"wasm1v8484th79cv2vh49sq949auu20yla3jh7rypzytp50quyly552vs3a4ugd",
"osmo-test-4":
"osmo1sm8weyvz7ues2mx9eg6rnqu9yazjdwru5p6u7u0jkhgmk6vqt8equ8t5xp",
"uni-3": "juno1yfp9zyx9zhqe77d05yqjx3ctqjhzha0xn5d9x8zxcpp658ks2hvqlfjt72",
"constantine-1":
"archway1wnuakyjhvlnepk2g9ncvvaks0zy0axgx70pet4jh2nv8lmsuff9qseuvpc"
};
​
export default contractAddress;
To query CosmJS, use the queryContractSmart() function. To conduct the query, the method is sent with the contract's address and message as a factor, and the resultant count number may be obtained using result.count. The code that fires the get count query can be found in src/contract/get_count.js.
import contractAddress from "./address";
​
const get_count = async (client, chainId) => {
const result = await client.queryContractSmart(contractAddress[chainId], {"get_count": {}});
return result;
}
​
export default get_count;
Because the reset and increment transactions modify the internal state of the contract, you must pay the gas cost.
You may execute a transaction by sending the execute() method along with the wallet address to pay for the gas, the contract address, the message, and the gas cost as a component. src/contract/reset.js contains the code that sends the reset transaction.
import { calculateFee, GasPrice } from "@cosmjs/stargate";
import contractAddress from "./address";
​
const reset = async (client, address, score, chainId, denom) => {
const gasPrice = GasPrice.fromString("0.025" + denom);
const executeFee = calculateFee(300_000, gasPrice);
const result = await client.execute(
address,
contractAddress[chainId],
{ reset: { count: score } },
executeFee
);
return result;
};
​
export default reset;

Clicker Game Implementation

We previously used src/App.js to send the play button to the /play location.
First, add the router from the src/index.js file so that when you connect to the /play URL, the play screen shows.
const root = ReactDOM.createRoot(document.getElementById("root"));
root.render(
<React.StrictMode>
<div className="App-header">
<BrowserRouter>
<Routes>
<Route path="/" element={<App />} />
<Route path="/play" element={<Play />} />
</Routes>
</BrowserRouter>
​
<div className="footer-container">
<span>Made with</span>
<img src="./dsrv.png" id="footer-logo" alt="dsrv-logo"></img>
</div>
</div>
</React.StrictMode>
);
src/pages/play.js implements the play screen that shows when you connect to the /play location. The final play page that we will use is as follows.
The previous and current scores are displayed in the upper left corner, while the time remaining is displayed in the top right corner. In the center, there is a GAME START button, which turns to TRANSACTION after the game is over.
The symbol exists in the game container, appears at the start of the game, and then disappears. While the transaction is ongoing, a loading message is displayed.
// The game begins before the game begins, and the TRANSACTION button appears after the game concludes.
const renderButton = () => {
if (gameOver === false) {
return (
<button className="game-btn" onClick={(event) => startGame(event)}>
GAME START
</button>
);
} else {
return (
<button className="game-btn" onClick={(event) => submitScore(event)}>
TRANSACTION
</button>
);
}
};
When the GAME START button is pushed, the count value acquired by calling the get_count function is shown in Previous Score, and the reset method is called to reset the contract's 'count' value to zero.
To communicate with the smart contract, you must first have client. When the screen is first shown using the useEffect function, use the chainId information from the App.js screen to connect to the wallet and construct 'client'. To use the information supplied from App.js to state, you must use the 'useLocation' function.
The function SigningCosmWasmClient.connectWithSigner() returns the SigningCosmWasmClient with the RPC endpoint address and OfflineSigner as a factor retrieved from Keplr. The 'client' serves as an interface with the network.
const location = useLocation();
​
// when page is rendered, the client object is created and saved
useEffect(() => {
const getClient = async (chainId) => {
// request access to Keplr wallet on the chainId
await window.keplr.enable(chainId);
// using chainId to retreive OfflineSigner
const offlineSigner = window.getOfflineSigner(chainId);
// SigningCosmWasmClient 생성
const client = await SigningCosmWasmClient.connectWithSigner(
networkInfo[chainId].rpc,
offlineSigner
);
setClient(client);
};
getClient(location.state.chainId);
}, []);
When the GAME START button is pushed, the startGame function reads the contract's count value using the previously created get_count method and puts it in the previousScore. Then, using the reset function, change the contract's count value to zero.
Begin the game after communicating with the contract. When the game begins, the time setting of 15 seconds should be reduced by one second each second. To implement the feature, use the setInterval method.
// Execute when Game Start button is clicked
const startGame = async(event) => {
// set loading status to true when communicating with a contract
setLoading(true);
// execute get_count query to retreive contract's count value
const result = await get_count(client, location.state.chainId);
// save count value retrieved from preiousScore
setPreviousScore(result.count);
// execute reset transaction to initialize count value to 0
await reset(client, location.state.address, 0, location.state.chainId, location.state.denom);
// set loading status to false after communicating with a contract
setLoading(false);
// intiialize true to Game Start value before starting a game
setGameStart(true);
// set a location to show up icons
setTargetPosition({ top: "20%", left: "50%" });
// Use the setInterval method to reduce time by 1 per second
setTimerId(
setInterval(() => {
setTime((time) => (time > 0 ? time - 1 : 0));
}, 1000)
);
}
The next time you click the CosmWasm symbol that displays when the game starts, your score will be increased by one and the technique will be executed to randomize the next location. And let's make the game stop after all 15 seconds have passed and the clock reaches zero.
Set the icon's location in a randomized fashion by utilizing the setTargetPosition and Math.random methods and increasing the current score by one.
// A function that run when you click the CosmWasm icon
const handleClick = () => {
// increment current score by 1
setScore((score) => score + 1);
// Random set to the following position on the icon.
setTargetPosition({
top: `${Math.floor(Math.random() * 80 + 10)}%`,
left: `${Math.floor(Math.random() * 80) + 10}%`
});
};
Using the useEffect function that detects a change in the time value, set the icon to disappear when time goes to zero and display the game end alarm window.
And use the clearInterval method to stop the continuously running 'setInterval' function
// play.js (added)
// End the game when time changes and becomes zero
useEffect(() => {
if (time === 0) {
// Icon is not disabled.
setTargetPosition({ display: "none" });
// Game Exit allamchang.
alert(
`Game Over! Your score is ${score}. Please confirm transaction to submit score.`
);
// setInterval function just halted
clearInterval(timerId);
setGameOver(true);
setGameStart(false);
}
}, [time]);
Create the submitScore method, which is called when you click the TRANSACTION button after the previous game has finished. Run increment as many times as the user's score, and after the increment transaction is complete, read the contract's count value again through the get_count function and update it to previousScore.
Since the contract's count value was reset to zero in the preceding requirement No. 2, the contract's count value is the score acquired by the user when the increment method is called.
After all contact with the contract has been completed, set the gameOver value to false and the zeroed time value back to 15 seconds to allow the game to be continued.
// Run when the Transaction button is pressed
const submitScore = async (event) => {
// Set loading status to true while communicating with the contract
setLoading(true);
// Execute the increment transaction by the score obtained by the user to change the count value of the contract to score
await increment(
client,
location.state.address,
score,
location.state.chainId,
location.state.denom
);
// Initialize with current score of 0
setScore(0);
// Read the count value stored in the contract through the get_count query and update to the Previous Score
const result = await get_count(client, location.state.chainId);
setPreviousScore(result.count);
// Set loading status to false after communication with contract
setLoading(false);
// Set the game to restart
setGameOver(false);
setTime(playTime);
};
The whole code may be obtained in this repository.
You can now use AllThatNode and CosmJS to publish Wasm Smart Contracts on the Osmosis Testnet and interface with Smart Contracts deployed on the front end through a simple clicker game.
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On this page
Step 0: Setting up your environments
Step 1: Faucet - Fund your Osmosis Account
Step 2: Compile a WebAssembly code
Step 3: Deploying a contract
Step 4: Execute a contract
Step 5: Communicate with frontend