postgres-integration

PostgreSQL Integration Example

This example demonstrates a production-like setup where PostgreSQL is used for both:

1. Persistence: Saving the scanner's current block height (cursor).
2. Sink: Storing the actual event data into a relational table.

Prerequisites

• A running PostgreSQL instance.
• Set the PG_URL environment variable.

How to Run

1. Start Postgres (using Docker):

   docker run --name some-postgres -e POSTGRES_PASSWORD=postgres -p 5432:5432 -d postgres
   

2. Run the example:

   export PG_URL="postgres://postgres:postgres@localhost:5432/postgres?sslmode=disable"
   go run main.go
   

What happens?

• The scanner will automatically create two tables:
  • demo_cursors: To track the last scanned block.
  • contract_events: To store decoded (or raw) logs with a unique constraint on (tx_hash, log_index) to prevent duplicates.
• You can query the data using:

  SELECT * FROM contract_events ORDER BY block_number DESC;