johninvictus / graphql_over_nsq

Absinthe Graphql over a message queue instead of HTTP

GraphQL over NSQ

An exploration of using a message queue as a GraphQL transport via elixir, absinthe, conduit and nsq. Checkout the corresponding article for more context.

Setup

This uses docker-compose to set everything up:

docker-compose up

Take note that everytime the services are up, do note it also resets the data so subsequent runs might require different ids.

Ports

The exposed ports to visit:

• http://localhost:14151/stats - NSQ Daemon Statistics

• http://localhost:14000/graphiql - Main API Gateway GraphiQL

• http://localhost:15000/graphiql - Account Service GraphiQL

• http://localhost:16000/graphiql - Product Service GraphiQL

• http://localhost:17000/graphiql - Transaction Service GraphiQL

GraphiQL

When using the api_gateway, you can execute the following queries:

List Users

List available users. By default, 5 random users are seeded.

query {
  users {
    id
    email
    firstName
    lastName
  }
}

Register User

Register a user.

mutation {
  registerUser($email: String!, $firstName: String!, $lastName: String!)
  {
    errors {
      field
      message
    }
    user {
      id
      email
      firstName
      lastName
    }
  }
}

Variables:

{
  "email": "[e-mail]",
  "firstName": "MY,
  "lastName": "NAME
}

List Products

List products. By default, 10 random products are seeded.

query {
  products {
    id
    code
    name
    price
  }
}

Create Transaction

Given an user and products, create a transaction for that person. The most complicated operation in this list.

To pretend we have authentication, we will use an user's email ($USER_EMAIL) from the users query as an OAuth token. In the GraphiQL interface

1. Click the Standard > OAuth 2 Bearer Token
2. In the dialog box, put the $USER_EMAIL after the Bearer text. You should have something like this.

Name:    Authorization
Value:   Bearer [e-mail]

mutation($items: [CreateTransactionItem!]!) {
  create_transaction(
    input: {
      items: $items
    }
  ) {
    errors {
      field
      message
    }
    transaction {
      id
      code
      items {
        id
        product_id
        price
        quantity
      }
    }
  }
}

Variables:

Replace $PRODUCT_ID with a Product.id from the products query.

{
  "itens": [
    {
      "productId": "$PRODUCT_ID",
      "quantity": 1
    }
  ]
}

User Transactions

Like listing all users, this also includes their transactions made.

query {
  users {
    id
    email
    transactions {
      id
      code
      items {
        product {
          id
          code
          name
          price
        }
        price
        quantity
      }
    }
  }
}