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Version: ArrowSquid

Quickstart: generate from ABI

With the abi template you can generate ready-to-use squids from EVM contract ABIs. Here we make a simple squid that decodes and indexes EVM logs and transactions of a single contract into a local Postgres database. Additionally, it serves the indexed data with a rich GraphQL API supporting pagination and filtering.

It is also possible to generate squids that handle data from multiple contracts and/or save the output to a file-based dataset.

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Squid generation tools are fully documented on this page.

Pre-requisites​

Before getting to work on your very first squid, verify that you have installed the following software:

  • Node v16.x or newer
  • Squid CLI v2.1.0 or newer
  • Docker
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With the exception of sqd init, sqd commands mentioned here are just scripts defined in commands.json that the sqd executable automatically discovers. Take a look at the contents of this file to learn more about how squids work under the hood.

Please note:

  • Squid templates are not compatible with yarn. Use npm instead.

Step 1: Scaffold from a template​

Come up with a new memorable name for your squid and scaffold from squid-abi-template using sqd init:

sqd init my-awesome-squid --template abi
cd my-awesome-squid
# install the dependencies
npm ci

Step 2: Generate the squid​

  • Consult the supported EVM networks page and find an archive endpoint for your network in the list.
  • Prepare the contract ABI and save it into the abi folder, e.g. as abi/usdc.json.
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For public contracts the ABI can be fetched automatically using an Etherscan-like API. To do so omit the --abi flag or, if your contract is a proxy, supply its address via --proxy and the address of the implentation via --address. For a full list of supported CLI options see

sqd generate --help

Generate the squid with

sqd generate \
--address <address> \
--abi <path to contract ABI> \ # optional
--archive <network archive alias or endpoint URL> \
--event '*' \
--function '*' \
--from <starting block>

The tool will attempt to grab the ABI from Etherscan API if --abi is omitted. Other compatible APIs can be used; for example, BSC contracts' ABIs can be retreved from BscScan with --etherscan-api https://api.bscscan.com/.

Example​

sqd generate \
--address 0x6B175474E89094C44Da98b954EedeAC495271d0F \
--archive eth-mainnet \
--event '*' \
--function '*' \
--from 1000000
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Squid generation tools can also be configured with YAML files. This mode unlocks advanced features such as working with multiple contracts and saving the squid data to file-based datasets.

Step 3: Launch Postgres in a detached Docker container​

sqd up

Step 4: Generate the schema migrations​

sqd migration:generate

Step 5: Run the squid processor​

Run the processor with

sqd process

The squid now ingests the contract transactions and event log data, decodes it and stores it in the database.

Step 6: Start the GraphQL server​

In a separate terminal window, run

sqd serve

This starts a GraphQL server serving the indexed events and transactions from the local database. The GraphQL playground is available at http://localhost:4350/graphql. Open it in a browser and run sample queries by applying filters and data selections in the panel to the left.

query MyQuery {
  contractEventTransfers(limit: 10) {
    id
    src
    dst
  }
}

What's next?​