Astar (WASM) Quick Start

SubQuery TeamAbout 6 min

Astar (WASM) Quick Start

Goals

This quick start guide introduces SubQuery's Substrate WASM support by using an example project in Astar Network. The example project indexes all Transactions and Approvals from the Astar Wasm based lottery contractopen in new window, as well as dApp staking events from Astar's dApp Stakingopen in new window functions.

This project is unique, as it indexes data from both Astar's Substrate execution layer (native Astar pallets and runtime), with smart contract data from Astar's WASM smart contract layer, within the same SubQuery project and into the same dataset. A very similar approach can be take with indexing Astar's EVM layer too.

Previously, in the 1. Create a New Project section, 3 key files were mentioned. Let's take a closer look at these files.

1. GraphQL Schema File

The schema.graphql file determines the shape of your data from SubQuery due to the mechanism of the GraphQL query language. Hence, updating the GraphQL Schema file is the perfect place to start. It allows you to define your end goal right at the start.

The Astar-wasm-starter project has four entities. A Transaction, Approval, DApp, and DAppReward (which has a foreign key to Dapp). These index basic block data such as the timestamp, heigh and hash along with from and contract addresses and the value.

type Transaction @entity {
  id: ID! # Transaction hash
  transactionHash: String
  blockHeight: BigInt
  blockHash: String
  timestamp: Date
  value: BigInt
  from: String!
  to: String!
  contractAddress: String!
}

type Approval @entity {
  id: ID! # Transaction hash
  blockHeight: BigInt
  value: BigInt
  hash: String
  owner: String!
  spender: String!
  contractAddress: String!
}

type DApp @entity {
  id: ID! #EVM is a required field
  accountID: String!
  totalStake: BigInt!
}

type DAppReward @entity {
  id: ID!
  dApp: DApp!
  accountID: String!
  eraIndex: Int!
  balanceOf: BigInt!
}

Important

When you make any changes to the schema file, please ensure that you regenerate your types directory.

You will find the generated models in the /src/types/models directory.

Check out the GraphQL Schema documentation to get in-depth information on schema.graphql file.

2. The Project Manifest File

The Project Manifest (project.yaml) file works as an entry point to your project. It defines most of the details on how SubQuery will index and transform the chain data. For Substrate/Polkadot chains, there are three types of mapping handlers:

BlockHanders: On each and every block, run a mapping function
EventHandlers: On each and every Event that matches optional filter criteria, run a mapping function
CallHanders: On each and every extrinsic call that matches optional filter criteria, run a mapping function

For EVM and WASM data processors on Substrate/Polkadot chains, there are only two types of mapping handlers:

EventHandlers: On each and every Event that matches optional filter criteria, run a mapping function
CallHanders: On each and every extrinsic call that matches optional filter criteria, run a mapping function

Substrate Manifest section

Since we are planning to index all Polkadot transfers, we need to update the datasources section as follows:

dataSources:
  - kind: substrate/Runtime
    # This is the datasource for Astar's Native Substrate processor
    startBlock: 1
    mapping:
      file: ./dist/index.js
      handlers:
        - handler: handleNewContract
          kind: substrate/EventHandler
          filter:
            module: dappsStaking
            method: NewContract
        - handler: handleBondAndStake
          kind: substrate/EventHandler
          filter:
            module: dappsStaking
            method: BondAndStake
        - handler: handleUnbondAndUnstake
          kind: substrate/EventHandler
          filter:
            module: dappsStaking
            method: UnbondAndUnstake
        - handler: handleReward
          kind: substrate/EventHandler
          filter:
            module: dappsStaking
            method: Reward

This indicates that you will be running a handleNewContract mapping function whenever there is an event emitted from the NewContract method on the dappsStaking pallet. Similarly we will run other mapping functions for the three other events being emitted from the dappsStaking to other mapping functions. This covers most interactions with the dApp staking feature that we are interested in.

Check out our Manifest File documentation to get more information about the Project Manifest (project.yaml) file.

WASM Manifest Section

If you're not using the WASM starter templateopen in new window then please add the Wasm Datasource as a dependency using yarn add @subql/substrate-wasm-processor.

We are indexing all transfers and approve contract call events from the Astar contract bZ2uiFGTLcYyP8F88XzXa13xu5Mmp13VLiaW1gGn7rzxktc. First, you will need to import the contract ABI defintion. You can copy the entire JSON and save it as a file ./erc20Metadata.json in the abis directory.

This section in the Project Manifest now imports all the correct definitions and lists the triggers that we look for on the blockchain when indexing. We add another section the datasource beneath the above substrate manifest section.

dataSources:
  - kind: substrate/Runtime
    # This is the datasource for Astar's Native Substrate processor
    ...
  - kind: substrate/Wasm
    # This is the datasource for Astar's Wasm processor
    startBlock: 3281780
    processor:
      file: ./node_modules/@subql/substrate-wasm-processor/dist/bundle.js
      options:
        abi: erc20
        # contract: "a6Yrf6jAPUwjoi5YvvoTE4ES5vYAMpV55ZCsFHtwMFPDx7H" # Shibuya
        contract: "bZ2uiFGTLcYyP8F88XzXa13xu5Mmp13VLiaW1gGn7rzxktc" # Mainnet
    assets:
      erc20:
        file: ./abis/erc20Metadata.json
    mapping:
      file: ./dist/index.js
      handlers:
        - handler: handleWasmEvent
          kind: substrate/WasmEvent
          filter:
            # contract: "a6Yrf6jAPUwjoi5YvvoTE4ES5vYAMpV55ZCsFHtwMFPDx7H" # Shibuya
            contract: "bZ2uiFGTLcYyP8F88XzXa13xu5Mmp13VLiaW1gGn7rzxktc" # Mainnet
            identifier: "Transfer"
        - handler: handleWasmCall
          kind: substrate/WasmCall
          filter:
            selector: "0x681266a0"
            method: "approve"

The above code indicates that you will be running a handleWasmEvent mapping function whenever there is an Transfer event on any transaction from the Astar contract. Similarly, we will run the handleWasmCall mapping function whenever there is a approve log on the same contract.

Check out our Substrate Wasm documentation to get more information about the Project Manifest (project.yaml) file for Substrate WASM contracts.

3. Mapping Functions

Mapping functions define how chain data is transformed into the optimised GraphQL entities that we previously defined in the schema.graphql file.

Navigate to the default mapping function in the src/mappings directory. There are multiple other exported functions such as handleWasmCall, handleWasmEvent, handleNewContract, handleBondAndStake, handleUnbondAndUnstake, and handleReward.

type ApproveCallArgs = [AccountId, Balance];

export async function handleWasmCall(
  call: WasmCall<ApproveCallArgs>
): Promise<void> {
  logger.info(`Processing WASM Call at ${call.blockNumber}`);
  const approval = new Approval(`${call.blockNumber}-${call.idx}`);
  approval.hash = call.hash;
  approval.owner = call.from.toString();
  approval.contractAddress = call.dest.toString();
  if (typeof call.data !== "string") {
    const [spender, value] = call.data.args;
    approval.spender = spender.toString();
    approval.value = value.toBigInt();
  } else {
    logger.info(`Decode call failed ${call.hash}`);
  }
  await approval.save();
}

The handleWasmCall function receives event data from the WASM execution environment whenever an call matches the filters that was specified previously in the project.yaml. It instantiates a new Approval entity and populates the fields with data from the Wasm Call payload. Then the .save() function is used to save the new entity (SubQuery will automatically save this to the database).

export async function handleBondAndStake(event: SubstrateEvent): Promise<void> {
  logger.info(
    `Processing new Dapp Staking Bond and Stake event at ${event.block.block.header.number}`
  );
  const {
    event: {
      data: [accountId, smartContract, balanceOf],
    },
  } = event;
  // Retrieve the dapp by its ID
  let dapp: DApp = await DApp.get(smartContract.toString());
  if (!dapp) {
    dapp = DApp.create({
      id: smartContract.toString(),
      accountID: accountId.toString(),
      totalStake: BigInt(0),
    });
  }

  dapp.totalStake += (balanceOf as Balance).toBigInt();
  await dapp.save();
}

The handleBondAndStake function receives Substrate event data from the native Substrate environment whenever an event matches the filters that was specified previously in the project.yaml. It extracts the various data from the event payload (in Substrate it's stored as an array of Codecs), then checks if an existing DApp record exists. If none exists (e.g. it's a new dApp), then it instantiates a new one and then updates the total stake to reflect the new staking mount. Then the .save() function is used to save the new/updated entity (SubQuery will automatically save this to the database).

Check out our mappings documentation for Substrate and the Substrate WASM data processor to get detailed information on mapping functions for each type.

4. Build Your Project

Next, build your work to run your new SubQuery project. Run the build command from the project's root directory as given here:

Important

Whenever you make changes to your mapping functions, make sure to rebuild your project.

5. Run Your Project Locally with Docker

SubQuery provides a Docker container to run projects very quickly and easily for development purposes.

The docker-compose.yml file defines all the configurations that control how a SubQuery node runs. For a new project, which you have just initialised, you won't need to change anything.

Run the following command under the project directory:

Tips

It may take a few minutes to download the required images and start the various nodes and Postgres databases.

Visit Running SubQuery Locally to get more information on the file and the settings.

6. Query Your Project

Once the container is running, navigate to http://localhost:3000 in your browser and run the sample GraphQL command provided in the README file. Below is an example query from the Astar-wasm-starter project.

query {
  transactions(first: 3, orderBy: BLOCK_HEIGHT_ASC) {
    totalCount
    nodes {
      id
      timestamp
      blockHeight
      transactionHash
      blockHash
      contractAddress
      from
      value
    }
  }
}

Tips

There is a Docs tab on the right side of the playground which should open a documentation drawer. This documentation is automatically generated and helps you find what entities and methods you can query. To learn more about the GraphQL Query language here.

You should see results similar to below:

{
  "data": {
    "transactions": {
      "totalCount": 17,
      "nodes": [
        {
          "id": "3281781-0",
          "timestamp": "2023-04-04T14:37:54.532",
          "blockHeight": "3281781",
          "transactionHash": "0x4f57e6ab4e8337375871fe4c8f7ae2e71601ea7fbd135b6f8384eb30db31ec44",
          "blockHash": "0x6d65fe39ae469afd74d32e34a61382b1bbda37983dea745ea2afe58e57d4afbc",
          "contractAddress": "bZ2uiFGTLcYyP8F88XzXa13xu5Mmp13VLiaW1gGn7rzxktc",
          "from": "WJWxmJ27TdMZqvzLx18sZpH9s5ir9irFm1LRfbDeByamdHf",
          "value": "25000000000000000000"
        },
        {
          "id": "3281792-0",
          "timestamp": "2023-04-04T14:40:06.386",
          "blockHeight": "3281792",
          "transactionHash": "0xbe8d6f09a96ff44e732315fbeff2862e9bdeb8353612a0bfab10632c410d8135",
          "blockHash": "0xaa09e8060068931a58a162c150ccb73e0b4de528185f1da92b049ab31c299e5a",
          "contractAddress": "bZ2uiFGTLcYyP8F88XzXa13xu5Mmp13VLiaW1gGn7rzxktc",
          "from": "aFNoZEM64m1ifrHAwEPEuhfRM5L7kjnPhmtYjZaQHX2zb6y",
          "value": "32000000000000000000"
        },
        {
          "id": "3281797-1",
          "timestamp": "2023-04-04T14:41:06.786",
          "blockHeight": "3281797",
          "transactionHash": "0xfdb111a314ee4e4460a3f2ab06221d5985c50e8f5cbae5a12f4f73b222d5954c",
          "blockHash": "0xeb4e49463e174fc993417e852f499ddc6e3c4a15f355a576a74772604f2132e5",
          "contractAddress": "bZ2uiFGTLcYyP8F88XzXa13xu5Mmp13VLiaW1gGn7rzxktc",
          "from": "aFNoZEM64m1ifrHAwEPEuhfRM5L7kjnPhmtYjZaQHX2zb6y",
          "value": "57000000000000000000"
        }
      ]
    }
  }
}

What's next?

Congratulations! You have now a locally running SubQuery project that accepts GraphQL API requests for events from the lottery smart contract at bZ2uiFGTLcYyP8F88XzXa13xu5Mmp13VLiaW1gGn7rzxktcopen in new window.

Tip

Find out how to build a performant SubQuery project and avoid common mistakes in Project Optimisation.

Click here to learn what should be your next step in your SubQuery journey.

Astar (WASM) Quick Start

# Astar (WASM) Quick Start

# Goals

# 1. GraphQL Schema File

# 2. The Project Manifest File

# Substrate Manifest section

# WASM Manifest Section

# 3. Mapping Functions

# 4. Build Your Project

# 5. Run Your Project Locally with Docker

# 6. Query Your Project

# What's next?

Astar (WASM) Quick Start

Goals

1. GraphQL Schema File

2. The Project Manifest File

Substrate Manifest section

WASM Manifest Section

3. Mapping Functions

4. Build Your Project

5. Run Your Project Locally with Docker

6. Query Your Project

What's next?