graphql-go

The goal of this project is to provide full support of the GraphQL draft specification with a set of idiomatic, easy to use Go packages.

While still under heavy development (internal APIs are almost certainly subject to change), this library is safe for production use.

Features

• minimal API
• support for context.Context
• support for the OpenTracing standard
• schema type-checking against resolvers
• resolvers are matched to the schema based on method sets (can resolve a GraphQL schema with a Go interface or Go struct).
• handles panics in resolvers
• parallel execution of resolvers

Roadmap

We're trying out the GitHub Project feature to manage graphql-go's development roadmap. Feedback is welcome and appreciated.

(Some) Documentation

Basic Sample

package main

import (
        "log"
        "net/http"

        graphql "github.com/graph-gophers/graphql-go"
        "github.com/graph-gophers/graphql-go/relay"
)

type query struct{}

func (_ *query) Hello() string { return "Hello, world!" }

func main() {
        s := `
                schema {
                        query: Query
                }
                type Query {
                        hello: String!
                }
        `
        schema := graphql.MustParseSchema(s, &query{})
        http.Handle("/query", &relay.Handler{Schema: schema})
        log.Fatal(http.ListenAndServe(":8080", nil))
}

To test:

$ curl -XPOST -d '{"query": "{ hello }"}' localhost:8080/query

Resolvers

A resolver must have one method for each field of the GraphQL type it resolves. The method name has to be exported and match the field's name in a non-case-sensitive way.

The method has up to two arguments:

• Optional context.Context argument.
• Mandatory *struct { ... } argument if the corresponding GraphQL field has arguments. The names of the struct fields have to be exported and have to match the names of the GraphQL arguments in a non-case-sensitive way.

The method has up to two results:

• The GraphQL field's value as determined by the resolver.
• Optional error result.

Example for a simple resolver method:

func (r *helloWorldResolver) Hello() string {
	return "Hello world!"
}

The following signature is also allowed:

func (r *helloWorldResolver) Hello(ctx context.Context) (string, error) {
	return "Hello world!", nil
}

Community Examples

tonyghita/graphql-go-example - A more "productionized" version of the Star Wars API example given in this repository.

deltaskelta/graphql-go-pets-example - graphql-go resolving against a sqlite database

OscarYuen/go-graphql-starter - a starter application integrated with dataloader, psql and basic authentication