alesr/gqlerrordemo

gqlerrordemo is a Go-based demonstration repository that illustrates handling GraphQL errors in a layered architecture.

gqlerrordemo

Overview

gqlerrordemo is a Go-based demonstration repository that illustrates handling GraphQL errors in a layered architecture. This project focuses on providing clear error handling within GraphQL operations.

Structure

• main.go: Initializes the server and integrates the GraphQL setup with custom error handling.
• gqlgen.yml: Configuration for gqlgen, a tool for building GraphQL servers in Go.
• schema.resolvers.go: Implements resolvers for the GraphQL schema.
• errors.go: Custom GraphQL error definitions and handling logic.
• resolver.go: Root resolver setup for the GraphQL API, integrating services and error handling.
• foo.go: Demonstrates domain logic with the Foo service.
• fakedb.go: Simulates database functionality, aiding in error generation and handling.

Features

• GraphQL Server: Utilizes gqlgen for server setup and operations.
• Custom Error Handling: Showcases creation and management of custom GraphQL errors.
• Layered Architecture: Demonstrates separation of concerns in service, resolver, and database simulation layers.
• Error Presenter: Customizes how errors are formatted and presented in GraphQL responses.

Using gqlerrordemo

Start the server (go run main.go) and access the GraphQL playground (http://localhost:8080).

Example Queries and Mutations

Create a Foo with Missing ID

mutation {
  createFoo(id: "") {
    id
  }
}

Response:

{
  "errors": [
    {
      "message": "Foo missing id",
      "path": ["createFoo"],
      "extensions": { "code": "FOO_MISSING_ID" }
    }
  ],
  "data": { "createFoo": null }
}

Create a Foo with an ID that Already Exists

mutation {
  createFoo(id: "alreadyexists") {
    id
  }
}

Response:

{
  "errors": [
    {
      "message": "Foo already exists",
      "path": ["createFoo"],
      "extensions": { "code": "FOO_ALREADY_EXISTS" }
    }
  ],
  "data": { "createFoo": null }
}

Successful Creation of a Foo

mutation {
  createFoo(id: "123") {
    id
  }
}

Response:

{
  "data": { "createFoo": { "id": "123" } }
}

Retrieving a Foo

query {
  getFoo(id: "123") {
    id
  }
}

Response:

{
  "data": { "getFoo": { "id": "foo" } }
}

Retrieving a Non-Existent Foo

query {
  getFoo(id: "notfound") {
    id
  }
}

Response:

{
  "errors": [
    {
      "message": "Foo not found",
      "path": ["getFoo"],
      "extensions": { "code": "FOO_NOT_FOUND" }
    }
  ],
  "data": { "getFoo": null }
}

Retrieving a Foo with Missing ID

query {
  getFoo(id: "") {
    id
  }
}

Response:

{
  "errors": [
    {
      "message": "Foo missing id",
      "path": ["getFoo"],
      "extensions": { "code": "FOO_MISSING_ID" }
    }
  ],
  "data": { "getFoo": null }
}

Conclusion

gqlerrordemo provides a hands-on experience with effective error handling in a GraphQL server using a layered architecture in Go. The included examples in the GraphQL playground demonstrate the handling of various scenarios, offering insights into implementing similar structures in your own projects.