Substrate Indexer Setup Guide

This guide will help you set up and run a Subsquid-based indexer for a Substrate chain. The indexer tracks balance transfers and can be extended to track other events and calls.

Prerequisites

• Node.js (v16 or later)
• Docker

Setup

1. Install dependencies:

npm install

Install sqd command line

npm install -g @subsquid/cli

2. Create a .env file in the root directory with your RPC endpoint:

RPC_ENDPOINT=ws://localhost:9944  # For local node
# or
RPC_ENDPOINT=wss://your-testnet-endpoint  # For testnet

3. Generate types and code for your chain:

sqd typegen
sqd codegen
sqd build

Running the Indexer

InitialSchema1790849787837 replaces InitialSchema1790651935090. TypeORM records applied migrations by name, so a database from the previous migration still looks pending. sqd migration:apply and sqd run refuse to continue while indexer tables are already present. Drop that database and reindex. The processor rebuilds chain totals from chain history.

Clean reindex (required for a database created by an earlier migration):

sqd down
sqd up
sqd migration:apply
sqd run

sqd down removes the local Postgres container. docker-compose-dev.yml does not mount a data volume, so the next sqd up is an empty database.

Resume when InitialSchema1790849787837 is already applied:

sqd up
sqd run

Start the processor and GraphQL API:

sqd run

If you only want to start the processor but not the rest of the system, use this instead

sqd process

Development

• The processor configuration is in src/processor.ts
• The GraphQL schema is in schema.graphql
• The database migrations are in db/migrations

Current Features

• Tracks balance transfers
• Stores transfer amounts, fees, and account information
• Provides GraphQL API for querying the indexed data

Reversible Transfers

This indexer also tracks the full lifecycle of reversible transfers:

• Scheduled: When a new reversible transfer is created.
• Executed: When a scheduled transfer is successfully completed.
• Cancelled: When a scheduled transfer is cancelled before execution.

The indexer creates or updates ReversibleTransfer entities in the database and creates a single Event entity when a transfer is first scheduled.

Querying Data

The GraphQL server provides a flexible API for querying the indexed data. Here are a few examples:

Extending

To add new events or calls to track:

1. Update the processor configuration in src/processor.ts
2. Update the GraphQL schema in schema.graphql
3. Generate new migrations:

sqd migration:generate

Troubleshooting

If you encounter issues:

1. Make sure Docker is running
2. Check that your RPC endpoint is correct in .env
3. Drop the database and reindex:

sqd down
sqd up
sqd migration:apply
sqd run

In case we need to redo this - how to create a new subsquid project

1. Install Subsquid CLI globally:

npm install -g @subsquid/cli

2. Initialize a new Subsquid project:

sqd init substrate-indexer --template substrate
cd substrate-indexer

Additional Resources

For more detailed information about the project structure and advanced features, please refer to the original README in the substrate-indexer directory.

License

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