jrhuerga / wecodefest-graphql

GraphQL using AWS App Sync

This tutorial explains how to take advantage of the GraphQL features of AWS App Sync.

DynamoDB Setup

Create two tables in AWS DynamoDB:

• Movies - Primary key: 'id' (number)
• Reviews - Primary key: 'id' (number)

Lambda Functions

Import in Lambda the following six functions (Node.js 8.x):

• MovieList - Used to list all the entries in the table Movies
• MovieAdd - Used to add a new entry in the table Movies
• MovieGet - Used to retrieve a single element in the table Movies
• ReviewList - Used to list all the entries in the table Reviews
• ReviewAdd - Used to add a new entry in the table Reviews
• ReviewGet - Used to retrieve a single element in the table Reviews

During the creation of the first lambda, you will need to create a new custom role. Edit that role in the IAM console and attach to it the policy AmazonDynamoDBFullAccess.

API Gateway

Create in AWS API Gateway the Movies API with the following resources and methods:

• /
  • /movies
    • GET - Associate it with MovieList lambda
    • POST - Associate it with MovieAdd lambda
    • /{id}
      • GET - Associate it with MovieGet lambda

Be careful to always select "Use Lambda Proxy integration". Create as well the Reviews API with this list of resources and methods:

• /
  • /reviews
    • GET - Associate it with ReviewList lambda. Add a URL query string parameter named 'idMovie'
    • POST - Associate it with ReviewAdd lambda
    • /{id}
      • GET - Associate it with ReviewGet lambda

Deploy both APIs in a new stage named 'beta'.

Populate data

Use this Postman collection to interact with the APIs and create an initial dataset. You will need to create a new Postman environment with these variables:

• movies - link to the Movies API in the beta stage created in previous step.
• reviews - link to the Reviews API

Use the different requests in the collection to verify that all the endpoints are working properly.

App Sync

Create a new AWS App Sync API named Movies. Use the file schema.graphql to create the Schema.

Create two datasources of type HTTP:

• movies - Linking to the URL in API Gateway of the Movies API
• reviews - Linking to the URL in API Gateway of the Reviews API

Define resolvers for the following types, queries and mutations:

• Movie.reviews - Data Source: reviews. Configure the request mapping template using this file
• Mutation.newMovie - Data Source: movies.Configure the request mapping template using this file
• Query.getMovie - Data Source: movies. Configure the request mapping template using this file
• Query.getMovies - Data Source: movies. Configure the request mapping template using this file
• Query.getReviews - Data Source: reviews. Configure the request mapping template using this file

Test GraphQL API

Use the file queries.graphql to verify the GraphQL API using the Queries tab provided by AWS App Sync

Alternatively you can use the GraphQL Playground of Prisma ( https://github.com/prisma/graphql-playground ) to test the GraphQL API. You will need to get the API Key from the Settings tab and pass it as a x-api-key header.