Please read over the Uniswap v3 documentation to understand the basics of Uniswap v3.
The Uniswap v3 API Provider allows you to interact with the Uniswap v3 pools - otherwise known as concentrated liquidity pools (CLPs) - on the Ethereum blockchain. The provider utilizes JSON-RPC to interact with an ethereum node - batching multiple requests into a single HTTP request to reduce latency and improve performance.
Uniswap v3 shows the current price of the pool in slot0 of the pool contract. slot0 is where most of the commonly accessed values are stored, making it a good starting point for data collection. You can get the price from two places; either from the sqrtPriceX96 or calculating the price from the pool tick value. Using sqrtPriceX96 should be preferred over calculating the price from the current tick, because the current tick may lose precision due to the integer constraints. As such, this provider uses the sqrtPriceX96 value to calculate the price of the pool.
Based on the analysis of various approaches for querying EVM state, this implementation utilizes BatchCallContext available on any client that implements the go-ethereum's ethclient interface. This allows for multiple requests to be batched into a single HTTP request, reducing latency and improving performance. This is preferable to using the multicall contract, which is a contract that aggregates multiple calls into a single call.
To generate the ABI for the Uniswap v3 pool contract, you can use the abigen tool provided by the go-ethereum library. The ABI is used to interact with the Uniswap v3 pool contract.
abigen --sol ./contracts/UniswapV3Pool.sol --pkg uniswap --out ./uniswap_v3_pool.go