enhancement: generate GraphQL schema from JSON ABI

[lostman]

Description

Closes #846.

This PR adds a --json-abi flag to forc index new which facilitates automatic generation of the GraphQL schema from the given JSON ABI.

Testing steps

Create a new indexer:

cargo run -p forc-index -- new --json-abi ./packages/fuel-indexer-tests/trybuild/abi/DAO-contract-abi.json dao-indexer

Copy the JSON ABI:

cp ./packages/fuel-indexer-tests/trybuild/abi/DAO-contract-abi.json /tmp/dao-indexer

Set the abi in the Manifest

abi: DAO-contract-abi.json

Change lib.rs to refer to types from the generated schema:

extern crate alloc;
use fuel_indexer_utils::prelude::*;

#[indexer(manifest = "dao_indexer.manifest.yaml")]
pub mod dao_indexer_index_mod {

    fn dao_indexer_handler(ie: InitializeEvent) {
        info!("author: {:?}", ie.author);
        let iee = InitializeEventEntity::new(ie.author, ie.token);
        iee.get_or_create();
    }
}

Verify that it builds:

forc index build

Changelog

• Add generate_schema(), which generates a GraphQL schema from JSON ABI.
• Add documentation.
• Move some functions from packages/fuel-indexer-macros/src/helpers.rs to packages/fuel-indexer-lib/src/helpers.rs because they are now used in both places.

[ra0x3]

@lostman

• Left some feedback
• Mainly about restructuring this a bit, and using fuel_indexer_macro_utils

[ra0x3]

This should go int the Designing a schema section maybe under a section called Automatic Schema Generation (or something that makes it clear what this section is about).

[ra0x3]

• I think this has to be re-written.
• @lostman We spent weeks on the docs, combing through every single line making sure they read properly and that all examples are informative and work
  • It sucked, it wasn't fun, but the docs are so much better now
  • Let's keep this trend going with the docs in this PR.
  • Ideally the docs should:
    1. Show me the tiniest Sway smart contract with various simple types (struct, enum, etc)
    2. Show me how to use forc index new --json-abi
    3. Show me the resultant schema that gets produced from that command ☝🏼
  • I think we have an example of this in the docs already here (again, I want to be very clear that I realize this is a PITA 😅 )

[ra0x3]

@lostman

• Ah ok, yea, as I mentioned in the "Is there any particular reason..." comment...
  • All of this codegen logic needs to be moved to fuel-indexer-macros (we're duplicating a ton of logic here)

So maybe something like:

• fuel_indexer_macros::schema_gen
  • This is where you put all the logic related to auto-creating this schema
    • And you would just pull in fuel_indexer_macros::helpers instead of duplicating this stuff
    • We already have a fuel_indexer_macro_utils crate
      • This was previously being used for indexer-internal proc macros (as opposed to public macros)
      • You could potentially move that #[metrics] macro out of fuel_indexer_macro_utils and into fuel_indexer_macros (so now fuel_indexer_macros would export #[metrics] and #[indexer]
      • Then that would allow you to put your macro logic in fuel_indexer_macro_utils (after you make it a non-proc-macro crate)
      • Finally, this would allow you to import the macro functions into forc_index::new via use fuel_indexer_macro_utils::schema_gen::*
        • I think this solves a lot of problems but let me know what you think

[lostman]

The issue is that fuel-indexer-macros is a proc-macro crate and can only export macros.

So, fuel_indexer_macros::schema_gen doesn't work.

we're duplicating a ton of logic here

Not duplicating. I moved the code from fuel_indexer_macros::helpers.

Finally, this would allow you to import the macro functions into forc_index::new via use fuel_indexer_macro_utils::schema_gen::*

This is fine. I can move this logic there and make it non-proc-macro.

[ra0x3]

@lostman I mentioned in my previous comment

Then that would allow you to put your macro logic in fuel_indexer_macro_utils (after you make it a non-proc-macro crate)

[ra0x3]

👌🏼