feat: events fetcher & indexer client

[0xkenj1]

🤖 Linear

Closes GIT-53 GIT-84 GIT-85

Description

Implementation of

• data-flow => EventsFetcher
• indexer-client => EnvioIndexerClient

Checklist before requesting a review

• I have conducted a self-review of my code.
• I have conducted a QA.
• If it is a core feature, I have included comprehensive tests.

[linear]

GIT-53 EventsFetcher

GIT-84 indexer-client

GIT-85 data-flow => `EventsFetcher`

[0xnigir1]

add natspec

[0xnigir1]

does this library provide a way to type the response?

[0xkenj1]

will investigate about that , maybe we can use some generics :)

[jahabeebs]

I think this is ok for now but rather than using string interpolation we can use variables which also prevent injection issues

see variables:
https://graphql.org/learn/queries/

in this case I think you could do this

const query = gql`
    query getEventsByChainIdBlockNumberAndLogIndex($chainId: Int!, $blockNumber: Int!, $logIndex: Int!, $limit: Int!) {
        raw_events(
            where: {
                chain_id: { _eq: $chainId }
                block_number: { _gte: $blockNumber }
                log_index: { _gt: $logIndex }
            }
            limit: $limit
        ) {
            block_number
            block_timestamp
            chain_id
            contract_name
            event_name
            log_index
            params
            src_address
        }
    }
`;

const response = await this.client.request(query, {
    chainId, blockNumber, logIndex, limit,
});

[0xkenj1]

thanks for this recommendation, this makes lot more sense :)

[0xyaco]

Starting to get deep into the core of the project 🫡

[0xyaco]

Should blockNumber be a BigInt?

[0xyaco]

Now I'm thinking if ProtocolEvent["block_number"] should also be bigint 🤔

[0xkenj1]

Not sure if we need it actually. Number.MAX_SAFE_INTEGER = 9007199254740991 :rofl

[0xnigir1]

Viem treats it like bigint, we will have an inconsistency here. We need to define a common type at least to the internal limits of our backend, and only convert to number or bigint when interfacing with external (IndexerClient, Viem lib, etc)

[0xyaco]

Along the lines of Nigiri's comment, it's more of a semantic type thingy.

Whenever you get a block number out of viem or any other client, you as a dev will need to know (and be extremely sure) that you are working with a particular set of block numbers that can be safely casted from bigint to number. By using a bigint, you just forget about that problem in the future. You move from a "it will probably work" scenario to a "it works" scenario.

[0xyaco]

Super small detail but feels like it could be more descriptive to name this method as

Suggested change

	public async getEventsByBlockNumberAndLogIndex(
	public async getEventsAfterBlockNumberAndLogIndex(

[0xyaco]

Interested in seeing if it's possible to type gql requests, would be awesome

[0xnigir1]

as Yaco said, would be great to type the GraphQL queries (maybe defining the queries in a separate .gql file or the schemas)