SubQuery - Example Project for Polkadot

SubQuery is a fast, flexible, and reliable open-source data indexer that provides you with custom APIs for your web3 project across all of our supported networks. To learn about how to get started with SubQuery, visit our docs.

This SubQuery project indexes all asset transfers using the balances pallet on the Polkadot Network

Tl;Dr

npm install -g @subql/cli
npm install
npm run codegen
npm run build
docker-compose pull
docker-compose up --remove-orphans

Or you can use this one-liner which will install dependencies and setup the the indexer after taking user inputs for websocket endpoint and genesis hash.

curl -s https://raw.githubusercontent.com/kaustubhkapatral/avail-indexer/main/setup_indexer.sh -o setup_indexer.sh && bash setup_indexer.sh

Start

First, install SubQuery CLI globally on your terminal by using NPM npm install -g @subql/cli

You can either clone this GitHub repo, or use the subql CLI to bootstrap a clean project in the network of your choosing by running subql init and following the prompts.

Don't forget to install dependencies with npm install or yarn install!

Editing your SubQuery project

Although this is a working example SubQuery project, you can edit the SubQuery project by changing the following files:

The project manifest in project.yaml defines the key project configuration and mapping handler filters
The GraphQL Schema (schema.graphql) defines the shape of the resulting data that you are using SubQuery to index
The Mapping functions in src/mappings/ directory are typescript functions that handle transformation logic

SubQuery supports various layer-1 blockchain networks and provides dedicated quick start guides as well as detailed technical documentation for each of them.

For Kate Testnet:

 genesisHash: '0xd12003ac837853b062aaccca5ce87ac4838c48447e41db4a3dcfb5bf312350c6'
 endpoint: 'wss://kate.avail.tools/ws'

For Biryani Devnet:

 genesisHash: '0x25b7a5d31af1def763db74809b08794c4eb2121c531f8fd8458555be487bebda'
 endpoint: 'wss://biryani-devnet.avail.tools/ws'

Run your project

If you get stuck, find out how to get help below.

The simplest way to run your project is by running yarn dev or npm run-script dev. This does all of the following:

yarn codegen - Generates types from the GraphQL schema definition and contract ABIs and saves them in the /src/types directory. This must be done after each change to the schema.graphql file or the contract ABIs
yarn build - Builds and packages the SubQuery project into the /dist directory
docker-compose pull && docker-compose up - Runs a Docker container with an indexer, PostgeSQL DB, and a query service. This requires Docker to be installed and running locally. The configuration for this container is set from your docker-compose.yml

You can observe the three services start, and once all are running (it may take a few minutes on your first start), please open your browser and head to http://localhost:3000 - you should see a GraphQL playground showing with the schemas ready to query. Read the docs for more information or explore the possible service configuration for running SubQuery.

Query your project

For this project, you can try to query with the following GraphQL code to get a taste of how it works.

# Query blocks (events, logs, ... can be called separately)
{
  blocks(first: 10, orderBy: TIMESTAMP_DESC) {
    nodes {
      number
      hash
      parentHash
      stateRoot
      timestamp
      runtimeVersion
      extrinsics {
        nodes {
          module
          call
        }
      }
      events {
        nodes {
          module
          call
        }
      }
      logs {
        nodes {
          type
          engine
          data
        }
      }
      headerExtensions {
        nodes {
          version
          commitments {
            nodes {
              rows
              cols
              dataRoot
              commitment
            }
          }
        }
      }
    }
  }
}
# Query session and validators
{
  sessions(
    filter: {
      id: {equalTo: "2907"}
    }
    first: 10
    orderBy: ID_DESC
  ) {
    totalCount
    nodes {
      id
      validators
    }
  }
}
# Query accounts
{
  accountEntities(
    filter: { id: { in: ["5CwCDQKRyPnrSHcmxbS9cEDGb4YQxaVrbQmw9RH5yBR9Xnh5"] } }
  ) {
    nodes {
      id
      amount
      amountTotal
      amountRounded
      amountTotalRounded
    }
  }
}

You can explore the different possible queries and entities to help you with GraphQL using the documentation drawer on the right (schema and docs).

Get help from chat GPT (Change the query between "")

Giving this example requests :

# Copy paste the examples from "Query your project" section

And this schema :

# Copy the content of schema.graphql here

And the fact that foreign key such as "Block" becomes blockId in a query

Can you generate me a query to :

"query the first 10 extrinsics where the call is "submitData" ordered by blockId desc ?"

When changing the service file

Put the file in /etc/systemd/system/
sudo systemctl daemon-reload
sudo systemctl enable start_indexer.service
sudo systemctl start start_indexer.service