Crate graphql_codegen_rust 

GraphQL Code Generator for Rust ORMs

Transform GraphQL schemas into production-ready Rust code for Diesel and Sea-ORM. Automatically generates entities, migrations, and schema definitions from your GraphQL API’s introspection.

Key Features

• Dual ORM Support: Generate code for both Diesel and Sea-ORM
• Database Agnostic: Support for SQLite, PostgreSQL, and MySQL
• Type Safety: Compile-time guarantees with full GraphQL type mapping
• Migration Ready: Automatic database migration generation
• Introspection Powered: Works with any GraphQL API that supports introspection
• Flexible Configuration: TOML and YAML config support (with feature flag)

Quick Start

1. Install the CLI

cargo install graphql-codegen-rust

2. Initialize your project

graphql-codegen-rust init --url https://api.example.com/graphql

3. Generate code

graphql-codegen-rust generate

Library Usage

For programmatic use in your Rust applications:

use graphql_codegen_rust::{CodeGenerator, Config};
use graphql_codegen_rust::cli::{OrmType, DatabaseType};

// Create configuration programmatically
let config = Config {
    url: "https://api.example.com/graphql".to_string(),
    orm: OrmType::Diesel,
    db: DatabaseType::Postgres,
    output_dir: "./generated".into(),
    headers: std::collections::HashMap::new(),
    type_mappings: std::collections::HashMap::new(),
    scalar_mappings: std::collections::HashMap::new(),
    table_naming: Default::default(),
    generate_migrations: true,
    generate_entities: true,
};

// Generate code
let generator = CodeGenerator::new(&config.orm);
generator.generate_from_config(&config).await?;

Configuration

TOML Configuration (graphql-codegen-rust.toml)

url = "https://api.example.com/graphql"
orm = "Diesel"
db = "Postgres"
output_dir = "./generated"

[headers]
Authorization = "Bearer your-token-here"

[type_mappings]
# Custom type mappings if needed

YAML Configuration (codegen.yml) - Requires yaml-codegen-config feature

schema:
  url: https://api.example.com/graphql
  headers:
    Authorization: Bearer your-token-here

rust_codegen:
  orm: Diesel
  db: Postgres
  output_dir: ./generated

Generated Code Structure

generated/
├── src/
│   ├── schema.rs          # Diesel schema definitions
│   ├── entities/
│   │   ├── user.rs       # Entity structs and implementations
│   │   └── post.rs
│   └── mod.rs            # Sea-ORM module definitions
└── migrations/
    └── 0001_create_users_table/
        ├── up.sql
        └── down.sql

Error Handling

The library uses anyhow for error handling, providing detailed error messages with context. Common error scenarios:

• Network errors: GraphQL endpoint unreachable or authentication failures
• Schema errors: Invalid GraphQL schema or introspection disabled
• Configuration errors: Missing or invalid configuration files
• Generation errors: Unsupported GraphQL types or ORM constraints

Feature Flags

• yaml-codegen-config: Enable YAML configuration file support
• Default features include TOML support and both Diesel and Sea-ORM generators

Requirements

• Rust 1.86+
• A GraphQL API that supports introspection
• Appropriate database dependencies based on your ORM choice

Re-exports

pub use config::Config;

pub use generator::create_generator;

Modules

cli

config

generator

introspection

parser

Structs

CodeGenerator

High-level interface for generating Rust ORM code from GraphQL schemas.

Functions

generate_all_code

generate_from_config_file

Generates ORM code directly from a configuration file path.