lychee

A simple example of GraphQL microservices federated in Golang. This project will soon provide some CMS features.

This repository is a work in progress...

Setup

go get -u github.com/aquiseb/lychee
go get ./...

Start

Open each microservice in a separate terminal tab. Start each of them with

cd micro-xxxxx
./start.sh

The federation of each of these microservices is done with the micro-federation module.

cd micro-federation
go run main.go

Failed downloading ...

https://github.com/oxequa/realize/issues/253#issuecomment-532045314

or

go get -v gopkg.in/urfave/cli.v2 \
&& go get -v github.com/oxequa/realize

Configuration

The configuration is handled by viper. Add a _config file in your microservice.

Versioning

Versioning is handled by govvv. To change the version, edit the VERSION file.

Build

Each microservice must be built separately. Add a VERSION file and specify the version of the microservice.

govvv build

Static assets

lychee uses go-bindata to convert any file into managable Go source code. Useful for embedding binary data (like GraphQL schemas) into a go program.

Write your microservice schema package, then generate bindata.go.

go-bindata -ignore=\.go -pkg=schema -o=schema/bindata.go schema/...

Here's how to use it from within main.go.

// GetSchema returns the schema of Post
func GetSchema() string {
	s, _ := schema.Asset("schema/schema.graphql")
	stringSchema := string(s)

	return stringSchema
}

Graphql Queries

Post

Simple

{
    post(id: "2") {
        title
        reviews {
        edges {
            node {
                id
                stars
            }
        }
    }
}

Advanced

{
  post(id: "1") {
    id
    title
    reviews {
      edges {
        node {
          id
          stars
          post {
            id
            title
            reviews {
              edges {
                node {
                  id
                  stars
                }
              }
            }
          }
        }
      }
    }
  }
}

lastname is provided by micro-post for the moment! This is an awesome federation feature.

{
  allUsers {
    id
    firstname
    lastname
  }
}

Troubleshooting

graphql: panic occurred: runtime error: invalid memory address or nil pointer dereference

Chances are that you forgot to pass DB to a resolver. Passing DB enables underlying connections (like ReviewConnection) or infinite subqueries to use DB.

s := PostReviewsResolver{
    DB:      p.DB,
    reviews: reviews,
}

Inspirations

• https://github.com/deltaskelta/graphql-go-pets-example