Optimism Quick Start

SubQuery TeamAbout 3 min

Optimism Quick Start

The goal of this quick start guide is to index all claim events from the Optimism airdrop contract. Check out the video or follow the step by step instructions below.

Please initialise an Optimism project

In the earlier Quickstart section , you should have taken note of three crucial files. To initiate the setup of a project from scratch, you can proceed to follow the steps outlined in the initialisation description.

As a prerequisite, you will need to generate types from the ABI files of each smart contract. Additionally, you can kickstart your project by using the EVM Scaffolding approach (detailed here). You'll find all the relevant events to be scaffolded in the documentation for each type of smart contract.

Note

The final code of this project can be found here. We use Ethereum packages, runtimes, and handlers (e.g. @subql/node-ethereum, ethereum/Runtime, and ethereum/*Hander) for Optimism. Since Optimism is a layer-2 scaling solution, we can use the core Ethereum framework to index it.

Your Project Manifest File

The Project Manifest file is an entry point to your project. It defines most of the details on how SubQuery will index and transform the chain data.

For EVM chains, there are three types of mapping handlers (and you can have more than one in each project):

BlockHanders: On each and every block, run a mapping function
TransactionHandlers: On each and every transaction that matches optional filter criteria, run a mapping function
LogHanders: On each and every log that matches optional filter criteria, run a mapping function

As we are indexing all claim events from the Optimism airdrop contract, the first step is to import the contract abi definition which can be obtained from here. Copy the entire contract ABI and save it as a file called airdrop.abi.json in the /abis directory.

Update the datasources section as follows:

{
  dataSources: [
    {
      kind: EthereumDatasourceKind.Runtime,
      startBlock: 100316590, // When the airdrop contract was deployed https://optimistic.etherscan.io/tx/0xdd10f016092f1584912a23e544a29a638610bdd6cb42a3e8b13030fd78334eba
      options: {
        // Must be a key of assets
        abi: "airdrop",
        // this is the contract address for Optimism Airdrop https://optimistic.etherscan.io/address/0xfedfaf1a10335448b7fa0268f56d2b44dbd357de
        address: "0xFeDFAF1A10335448b7FA0268F56D2B44DBD357de",
      },
      assets: new Map([["airdrop", { file: "./abis/airdrop.abi.json" }]]),
      mapping: {
        file: "./dist/index.js",
        handlers: [
          {
            kind: EthereumHandlerKind.Event,
            handler: "handleClaim",
            filter: {
              topics: [
                "Claimed(uint256 index, address account, uint256 amount)",
              ],
            },
          },
        ],
      },
    },
  ],
}

The above code indicates that you will be running a handleClaim mapping function whenever there is a Claimed log on any transaction from the Optimism airdrop contract.

Note

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

Update Your 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.

Remove all existing entities and update the schema.graphql file as follows. Here you can see we are indexing block information such as the id, blockHeight and timestamp along with the value and the total claimed amount.

type Claim @entity {
  id: ID! # Index
  transaction_hash: String!
  account: String!
  value: BigInt!
  block_height: BigInt!
  block_timestamp: BigInt!
  daily_claim_summary: DailyClaimSummary!
}

type DailyClaimSummary @entity {
  id: ID! # this is the ISO string of the day e.g. '2023-03-26'
  total_claimed: BigInt!
}

Note

Importantly, these relationships can not only establish one-to-many connections but also extend to include many-to-many associations. To delve deeper into entity relationships, you can refer to this section. If you prefer a more example-based approach, our dedicated Hero Course Module can provide further insights.

SubQuery simplifies and ensures type-safety when working with GraphQL entities, smart contracts, events, transactions, and logs. The SubQuery CLI will generate types based on your project's GraphQL schema and any contract ABIs included in the data sources.

yarn

yarn codegen

npm

npm run-script codegen

This action will generate a new directory (or update the existing one) named src/types. Inside this directory, you will find automatically generated entity classes corresponding to each type defined in your schema.graphql. These classes facilitate type-safe operations for loading, reading, and writing entity fields. You can learn more about this process in the GraphQL Schema section.

It will also generate a class for every contract event, offering convenient access to event parameters, as well as information about the block and transaction from which the event originated. You can find detailed information on how this is achieved in the EVM Codegen from ABIs section. All of these types are stored in the src/types/abi-interfaces and src/types/contracts directories.

You can conveniently import all these types:

import { Claim, DailyClaimSummary } from "../types";
import { ClaimedLog } from "../types/abi-interfaces/AirdropAbi";

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

Now that you have made essential changes to the GraphQL Schema file, let’s proceed ahead with the Mapping Function’s configuration.

Add a Mapping Function

Mapping functions define how blockchain 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. You will be able to see two exported functions: handleLog, and handleTransaction. Replace these functions with the following code:

import { ClaimedLog } from "../types/abi-interfaces/AirdropAbi";
import assert from "assert";
import { Claim } from "../types/models/Claim";
import { DailyClaimSummary } from "../types/models/DailyClaimSummary";

async function checkGetDailyClaim(
  timestamp: bigint,
): Promise<DailyClaimSummary> {
  // Create the ID from the iso date string (e.g. '2023-03-26')
  // Timestamps are in seconds, need to convert to ms
  const id = new Date(Number(timestamp) * 1000).toISOString().substring(0, 10);
  // Read to see if there is an existing aggregation record
  let dailyClaimSummary = await DailyClaimSummary.get(id);
  if (!dailyClaimSummary) {
    // This is a new day! Create a new aggregation
    dailyClaimSummary = DailyClaimSummary.create({
      id,
      total_claimed: BigInt(0),
    });
  }
  return dailyClaimSummary;
}

export async function handleClaim(log: ClaimedLog): Promise<void> {
  logger.info(`New claimed log at block ${log.blockNumber}`);
  assert(log.args, "No log.args");

  // We make sure we have a daily claim aggregation to update
  const dailyClaimSummary = await checkGetDailyClaim(log.block.timestamp);

  const newClaim = Claim.create({
    id: log.args.index.toString(),
    account: log.args.account,
    transaction_hash: log.transactionHash,
    block_height: BigInt(log.blockNumber),
    block_timestamp: log.block.timestamp,
    value: log.args.amount.toBigInt(),
    daily_claim_summaryId: dailyClaimSummary.id,
  });

  // We update the daily aggregation
  dailyClaimSummary.total_claimed += newClaim.value;

  // Save data to the store
  await dailyClaimSummary.save();
  await newClaim.save();
}

The handleClaim function receives a log parameter of type ClaimedLog which includes transaction log data in the payload. We extract this data, assign it to our newClaim object, and then save this to the store using the .save() function (Note that SubQuery will automatically save this to the database). We also call the checkGetDailyClaim function to retrieve the existing day aggregation (and create a new one if we need to), and the update the total_claimed on it.

Note

For more information on mapping functions, please refer to our Mappings documentation.

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:

yarn

yarn build

npm

npm run-script build

Important

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

Now, you are ready to run your first SubQuery project. Let’s check out the process of running your project in detail.

Whenever you create a new SubQuery Project, first, you must run it locally on your computer and test it and using Docker is the easiest and quickiest way to do this.

Run Your Project Locally with Docker

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.

However, visit the Running SubQuery Locally to get more information on the file and the settings.

Run the following command under the project directory:

yarn

yarn start:docker

npm

npm run-script start:docker

Note

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

Query your Project

Next, let's query our project. Follow these three simple steps to query your SubQuery project:

Open your browser and head to http://localhost:3000.
You will see a GraphQL playground in the browser and the schemas which are ready to query.
Find the Docs tab on the right side of the playground which should open a documentation drawer. This documentation is automatically generated and it helps you find what entities and methods you can query.

Try the following queries to understand how it works for your new SubQuery starter project. Don’t forget to learn more about the GraphQL Query language.

# Write your query or mutation q{here
query {
  claims(first: 5, orderBy: VALUE_DESC) {
    nodes {
      blockHeight
      value
      blockHeight
      blockTimestamp
      account
    }
  }
  dailyClaimSummaries(first: 5) {
    nodes {
      id
      totalClaimed
      claims(first: 5) {
        totalCount
        nodes {
          id
          account
          value
        }
      }
    }
  }
}

You will see the result similar to below:

{
  "data": {
    "claims": {
      "nodes": [
        {
          "blockHeight": "100322581",
          "value": "7477664852469040021504",
          "blockTimestamp": "1684714980",
          "account": "0x85399353400C5B67fD6eE53B1d2cd183bAE7dDdb"
        },
        {
          "blockHeight": "100316590",
          "value": "1746193727981909180416",
          "blockTimestamp": "1684711341",
          "account": "0xfa4d3CD41555d3A0FafD4A97e9ba91882A2f4755"
        }
      ]
    },
    "dailyClaimSummaries": {
      "nodes": [
        {
          "id": "2023-05-21",
          "totalClaimed": "9223858580450949201920",
          "claims": {
            "totalCount": 2,
            "nodes": [
              {
                "id": "247333",
                "account": "0xfa4d3CD41555d3A0FafD4A97e9ba91882A2f4755",
                "value": "1746193727981909180416"
              },
              {
                "id": "129721",
                "account": "0x85399353400C5B67fD6eE53B1d2cd183bAE7dDdb",
                "value": "7477664852469040021504"
              }
            ]
          }
        }
      ]
    }
  }
}

Note

The final code of this project can be found here.

What's next?

Congratulations! You have now a locally running SubQuery project that accepts GraphQL API requests for transferring data.

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.