TLDR

• Lido is a liquid staking solution on Ethereum, and here we build a subgraph to track its approval events.
• We scaffold a subgraph project with The Graph CLI, referencing Lido’s implementation contract address to download the correct ABI.
• By indexing the Approval event, we store each approval record as an entity in our subgraph, then deploy it to Chainstack.
• Finally, we can query approval events via the subgraph’s dedicated endpoint or the GraphQL UI.

Main article

Lido is a liquid staking solution with smart contracts deployed on multiple blockchains, with Ethereum being its main focus.

In this tutorial, we will learn how to deploy a subgraph to Chainstack.

Prerequisites

• A Chainstack account to deploy your subgraph.
• A basic understanding of The Graph protocol. The Graph docs are an excellent place to start.

Overview

To get from zero to a deployed subgraph with Chainstack:

• Create a subgraph in your project.
• Set up a subgraph development environment in your system.
• Configure your subgraph by creating new entities and handler functions.
• Deploy the subgraph using your Chainstack console.
• Query the subgraph using Chainstack’s Query URL or GraphQL UI URL.

Step-by-step

Create a subgraph project

📘

Subgraphs must be associated with a project. If you don’t already have a project to add the subgraph to, see create a project.

1. In Subgraphs, click Add subgraph.
2. In the Choose network section:
   • Choose a Blockchain protocol.
   • Choose the Network.
   • Choose the Type.
   • Click Next. The Create subgraph section is displayed.
3. In the Create subgraph section:
   • Enter a Name for the subgraph.
   • Select the Project that you want to assign your subgraph to.
   • Click Add subgraph. The details page of the new subgraph is displayed.

Set up a subgraph development environment

🚧

Before you begin

You need to have the following packages installed globally:

• A recent version of node.js
• graph-cli to compile and deploy subgraphs from the command line

1. Open up your terminal in the directory you want to create your project in. Then run:

   Shell

   graph init
   

2. This will open up a UI interface inside your command line. Set up your subgraph project with the following prompts:

   Shell

   Protocol: Ethereum
   Product for which to initialize: Subgraph-studio
   Subgraph slug: (**You can leave this empty**)
   Directory to create the subgraph in: LidoChainstack
   Ethereum network: mainnet
   Contract address: 0x47EbaB13B806773ec2A2d16873e2dF770D130b50
   Contract Name: Lido
   Index contract events as entities: Y
   

   The graph-cli will now download the ABI of the smart contract we provided and install all the dependencies of our project automatically. This might take a while.

3. You will now be asked if you want to add another smart contract to your subgraph. This is because a single subgraph can actually index multiple smart contracts. Say false, and then move your terminal into the directory of your newly created project.

Before moving on, let us take a look at what we did here. The original Lido smart contract is deployed here. You will notice that this is different from the address we used just now. This is because the Lido contract uses the EIP-897 DelegateProxy concept to implement an upgradeable smart contract.

This means if we use the actual smart contract address to set up our subgraph project, we will download the ABI of the proxy contract, which is not what we need.
The implementation contract is deployed here.

Configure the subgraph

A subgraph project consists of three main files:

• schema.graphql: this file defines the data sources we actually want to index, and how to query said data.
• subgraph.yaml: the subgraph manifest YAML file contains references to the contract ABIs, Graph QL schemas, and assembly script mappings, amongst other things.
• Subgraph mappings: mappings define event handlers in charge of managing and storing data on The Graph node.

Let us define a query for our subgraph.

1. The graph tries to generate some queries for us automatically by looking at the smart contract. Go to the schema.graphql file and delete everything. Now define a new entity as follows:

   schema.graphql

    type ApprovalQuery @entity(immutable: true) {
      id: ID!
      owner: Bytes!
      spender: Bytes!
      value: BigInt!
    }
   

   An entity can be thought of as an object that contains data. The data in our case comes from the Lido smart contract.

2. Go to subgraph.yaml and delete everything. Paste the following code inside it.

   subgraph.yaml

    specVersion: 0.0.5
    schema:
      file: ./schema.graphql
    dataSources:
      - kind: ethereum
        name: Lido
        network: mainnet
        source:
          address: "0xae7ab96520DE3A18E5e111B5EaAb095312D7fE84"
          abi: Lido
          startBlock: 11473216
        mapping:
          kind: ethereum/events
          apiVersion: 0.0.7
          language: wasm/assemblyscript
          entities:
            - ApprovalQuery
          abis:
            - name: Lido
              file: ./abis/Lido.json
          eventHandlers:
            - event: Approval(indexed address,indexed address,uint256)
              handler: ApprovalHandler
          file: ./src/lido.ts
   

   Here are the major changes we made to the YAML file:

   • Changed the contract address to the original address.
   • Added a start block property. This means that our subgraph will start indexing data only from this specific block number, which saves us indexing time and resources. The Lido contract was deployed at this block number, thus it makes no sense to index data older than this.
   • Referenced the name of our entity under the ‘entities’ object.
   • Our entity will index data that is emitted every time the Approval event is triggered in the Lido contract. For each event handler that is defined in the subgraph.yaml, we need to create a handler function in the src/lido.ts file. This file in each subgraph project is generally referred to as the mappings file.

   Whenever we update the schema file, the graph needs to generate some AssemblyScript code using the updated schema and the contract ABI. To do so, run:

   Shell

   graph codegen
   

3. Go to src/lido.ts and delete everything inside. Now paste the following code inside it:

   src/lido.ts

    import {
      Approval
    } from "../generated/Lido/Lido"
    import {
      ApprovalQuery
    } from "../generated/schema"
   
    export function ApprovalHandler(event: Approval): void {
      let entity = new ApprovalQuery(
        event.transaction.hash.toHex() + '-' + event.logIndex.toString()
      )
   
      entity.owner = event.params.owner
      entity.spender = event.params.spender
      entity.value = event.params.value
   
      entity.save()
    }
   

   The approval event is triggered whenever an address allows another address to spend some tokens on its behalf. In this code, we export a single function. This function declares a new object called entity that has three properties to mirror the emitted data from the approval event. We save this entity using entity.save(). Also, note that we use the transaction hash and logIndex to generate a unique ID for all our entities. You can read more about this in The Graph documentation.

4. Save all your files and run this command in your terminal:

   Shell

   graph build
   

   This command compiles your subgraph. And that’s it. We are now ready to deploy our subgraph.

Please note that this is a basic subgraph built to index data from the Lido smart contract. Lido has several smart contracts deployed on Ethereum, and they also have a GitHub repo for the subgraph they built to monitor their smart contracts. If you want to have a more detailed look at their contracts/subgraph, you can start here.

Deploy to Chainstack Subgraphs

1. Open your Chainstack Subgraphs console.

2. To deploy your subgraph, copy the deployment command and run it in a terminal at the root of your project directory.

   The deployment command from the Chainstack console will look like the following:

   Solidity

   graph deploy --node https://api.graph-eu.p2pify.com/API_KEY/deploy --ipfs https://api.graph-eu.p2pify.com/API_KEY/ipfs PROJECT_NAME
   

3. Run the command. Enter any version number of your choice and press Enter.

4. If your subgraph is successfully deployed, your terminal will look like this:

   Shell

   Deployed to https://chainstack.com/subgraphs/SG-123-456-789
   
   Subgraph endpoints:
   Queries (HTTP):     https://ethereum-mainnet.graph-eu.p2pify.com/3c6e0b8a9c15224a8228b9a98ca1531d/my_subgraph_v1_0
   

Query your Subgraph

You can use the Query URL to interact directly with your subgraph from within the terminal. Alternatively, you can use the GraphQL UI URL from your console to interact with your subgraph using your browser.

To use the Query URL, open your terminal and run the following CURL command:

curl -g \-X POST \-H "Content-Type: application/json" \-d '{"query":"{approvalQueries {id owner spender value} }"}' \<YOUR_CHAINSTACK_QUERY_URL>

To use GraphQL UI URL, copy the URL and open it in your browser.

Now run the following query:

{
  approvalQueries{
    id
    owner
    spender
    value
  }
}

This query will give us the requested data from any transaction that leads to the approval event being invoked from the main Lido contract.

Conclusion

This tutorial guided you through creating a new subgraph project and deploying it to your dedicated, super-fast Chainstack infrastructure.

📘

See also

• A beginner’s guide to getting started with The Graph
• Explaining Subgraph schemas
• Debugging subgraphs with a local Graph Node
• Indexing ERC-20 token balance using Subgraphs
• Indexing Uniswap data with Subgraphs
• Fetching subgraph data using JS

About the author

Priyank Gupta 🥑 Developer Advocate @ Chainstack 🛠️ BUIDLs on Ethereum, zkEVMs, The Graph protocol, and IPFS 🦀 Part-time Rust aficionado