reinhardt-graphql-macros

Derive macros for GraphQL-gRPC integration in Reinhardt framework

Overview

reinhardt-graphql-macros provides procedural macros to simplify the integration between gRPC and GraphQL in the Reinhardt framework. These macros automatically generate conversion code and subscription implementations to reduce boilerplate.

Important

This is an internal subcrate of reinhardt-graphql. Users should depend on reinhardt (the parent crate) instead of this crate directly.

# ✅ Correct - use the reinhardt parent crate
[dependencies]
reinhardt = { version = "0.1.0-alpha.1", features = ["graphql"] }

# Or use a preset:
# reinhardt = { version = "0.1.0-alpha.1", features = ["standard"] }  # Recommended
# reinhardt = { version = "0.1.0-alpha.1", features = ["full"] }      # All features

# ❌ Incorrect - don't depend on this crate directly
[dependencies]
reinhardt-graphql-macros = "0.1.0-alpha.1"

The macros are automatically re-exported by reinhardt::graphql:

// ✅ Correct - import from the reinhardt parent crate
use reinhardt::graphql::{GrpcGraphQLConvert, GrpcSubscription};

// Or use the macros module
use reinhardt::graphql::macros::{GrpcGraphQLConvert, GrpcSubscription};

Features

Implemented ✓

• GrpcGraphQLConvert - Automatic type conversion between Protobuf and GraphQL types

  • Derives From<proto::T> for T and From<T> for proto::T
  • Field renaming with #[graphql(rename_all = "camelCase")]
  • Conditional field inclusion with #[graphql(skip_if = "...")]
  • Custom protobuf type mapping with #[proto(...)] attributes

• GrpcSubscription - Automatic GraphQL subscription from gRPC streams

  • Maps gRPC streaming methods to GraphQL subscriptions
  • Service and method specification with #[grpc(service = "...", method = "...")]
  • Optional filtering with #[graphql(filter = "...")]
  • Rust 2024 lifetime compatibility

Usage

Type Conversion

use reinhardt::graphql::GrpcGraphQLConvert;

#[derive(GrpcGraphQLConvert)]
#[graphql(rename_all = "camelCase")]
struct User {
    id: String,
    name: String,
    #[graphql(skip_if = "Option::is_none")]
    email: Option<String>,
}

This generates:

• From<proto::User> for User
• From<User> for proto::User

gRPC Subscriptions

use reinhardt::graphql::GrpcSubscription;

#[derive(GrpcSubscription)]
#[grpc(service = "UserEventsServiceClient", method = "subscribe_user_events")]
#[graphql(filter = "event_type == Created")]
struct UserCreatedSubscription;

This automatically generates a GraphQL subscription implementation that:

• Connects to the gRPC service
• Subscribes to the specified method
• Applies the filter to incoming events
• Converts gRPC messages to GraphQL types

Attributes

GrpcGraphQLConvert Attributes

• #[graphql(rename_all = "...")] - Rename all fields (camelCase, snake_case, PascalCase)
• #[graphql(skip_if = "...")] - Skip field if predicate is true
• #[proto(type = "...")] - Specify custom protobuf type
• #[proto(rename = "...")] - Rename field in protobuf

GrpcSubscription Attributes

• #[grpc(service = "...")] - gRPC service client name
• #[grpc(method = "...")] - gRPC method name
• #[graphql(filter = "...")] - Filter expression for events

License

Licensed under either of Apache License, Version 2.0 or MIT license at your option.