graphql-example

GraphQL Endpoint and DynamoDB

Inspired by Kevin Old's project, this is a sample implementation a GraphQL service on AWS Lambda using Claudia. The service offers CRUD operations via just 1 endpoint. The data persistence is done via DynamoDB, similar to the dynamodb-example.

Prerequisites

Create a table in DynamoDB, with a string primary key called userid. You can do that from the DynamoDB web console, or using the AWS CLI command line. Here is an example command that will create the table with the minimal provisioned throughput:

aws dynamodb create-table --table-name claudia-graphql-example \
  --attribute-definitions AttributeName=userid,AttributeType=S \
  --key-schema AttributeName=userid,KeyType=HASH \
  --provisioned-throughput ReadCapacityUnits=1,WriteCapacityUnits=1 \
  --query TableDescription.TableArn --output text

This example project includes an IAM access policy that will grant the lambda function access to all your DynamoDB tables, to make it easier to get started. If you wish, you can edit the policies/access-dynamodb.json file and restrict the access to your new table only.

Get started

To set this up, first set up the credentials, then:

1. run npm install to grab the dependencies
2. run npm run create to create the lambda project under the default name on AWS.
3. run ./test/run.sh to execute cURL scripts to test the CRUD operations against the lambda endpoint.

For subsequent updates, use the npm run deploy command.

The API

With GraphQL, there is only 1 endpoint /latest/graphql for all CRUD operations. User construct a GraphQL query string based on the schema definition defined in src/schema.js, and post the string to the endpoint.

Create and Update

Post application/graphql that looks like this:

mutation {
  addUser (userid:"2", name:"John Doe", age:29) {
    userid
    name
    age
  }
}

Read

Post application/graphql that looks like this:

user (userid:"4") {
  userid
  name
  age
}

DELETE

Post application/graphql that looks like this:

mutation {
  deleteUser (userid:"4") {
    userid
    name
    age
  }
}

Testing

Via cURL

Run ./test/run.sh to launch the cURL scripts that perform the various operations.

Via GraphiQL

GraphiQL is an IDE that help user edit and test queries and discover the schema. You can download a GraphiQL app at https://github.com/skevy/graphiql-app