I will introduce then AppSync service and its characteristics. AppSync is an AWS managed service that has a lot of really interesting functionalities out of the box, for example, authentication or native connection with DynamoDB. Then we will move to a practical part where I will show you how to get started with your first Serverless GraphQL application using AppSync.

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Marcia Villalba – AWS Technical Evangelist
@mavi888uy
Serverless 🧡 GraphQL
A match made in heaven
Highload fwdays’19 – 5th Oct 2019

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About me
AWS since September 2019
Coding for more than 15 years
Serverless since 2016
Content creator
Before AWS I was working in gaming

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Speed to market
GraphQL? Serverless? 🤔

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Serverless
Brief introduction

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Serverless promises
No managing infrastructure High availability built in
Pay for what you useScales automagically

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Serverless
Backend as a service
(BAAS)
Function as a service
(FAAS)

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AWS Buildings blocks for serverless applications
Compute Storage Databases
API management Messaging Analytics
Orchestration Monitoring User Management
API Gateway
AWS Lambda
AppSync
Step functions Event Brigde
Amazon S3
Amazon SNS Amazon SQS
CloudWatch
DynamoDB
Amazon Kinesis Amazon Athena
Amazon Cognito

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What is GraphQL?
Let’s talk about the most important concepts

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GraphQL is a specification
Not a framework
Not a database
Not a server

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Graphql schema
Describe all the data the
client has available and what
the client can do using a type
system

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Graphql characteristics
Ask for what you need an get
exactly that.
No over fetching

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Graphql characteristics
Get many resources in one request.
No under fetching

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Graphql characteristics
Evolve your API without
versions

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Graphql - Characteristics
Connect to multiple
datasources Heroes database
Planets HTTP service
Species non relational
database

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What are datasources?
• A Database
• Another service with an API
• A HTTP request that return data
• A call to a search service
• Can be anything!

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GraphQL query language

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Graphql – Query Language
Everything is a type
Fields can be scalar or other types

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Graphql – Query Language
There are special types

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Graphql – Query Language
Entry point to the graphql query

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Graphql – Query Language
The client can write a query like this And get exactly what it needs

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Graphql – Query Language
Very complete language
Read more about it here: https://graphql.org/learn/

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How GraphQL works?

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How GraphQL works?
Client
GraphQL
SQL datasource
1.
Create the schema.
Describe all the available types and
operations

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How GraphQL works?
Client
GraphQL
SQL datasource
2.
Define all your resolvers, to be able
to serve all the operations defined in
the schema

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How GraphQL works?
Client
GraphQL
SQL datasource
3.
The client makes a request

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How GraphQL works?
Client
GraphQL
SQL datasource
4.
GraphQL uses the request resolver to
translate the client query and get
data from the datasource Translate GraphQL query into
SELECT video_id, video_name FROM videos

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How GraphQL works?
Client
GraphQL
SQL datasource
5.
GraphQL uses the response resolver
to return data from the datasource
to the client
In this case the resolver will
translate SQL into JSON

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How GraphQL works?
Client
GraphQL
SQL datasource
6.
GraphQL returns the JSON response
to the client

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GraphQL
or REST

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So when to use GraphQL?
- Creating a single entry point for your clients
Client
GraphQL
Orders service
Customers service
Product service

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So when to use GraphQL?
- When you want to add more functionality to an old service
Client
GraphQL
Old customers service

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So when to use GraphQL?
- When you want to simplify a complex API
Client
GraphQL
Very complex API

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Implementing GraphQL
Implement your own GraphQL server
Use an existing GraphQL server library
Use an existing GraphQL platform

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Existing GraphQL platforms
Apollo Platform (https://www.apollographql.com/platform/)
GraphCMS (https://graphcms.com/)
GraphCool (https://www.graph.cool/)
AppSync (https://aws.amazon.com/appsync/)

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AWS AppSync
Serverless GraphQL platform

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Appsync
AWS AppSync is a managed service for application data using GraphQL
with real-time capabilities and offline programming model
Real time Offline support Support for many
different Databases
Fine grained access
control

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AppSync Security
- API KEY authorization
- Amazon Cognito User Pools authorization
- OPEN ID Connect Authorization
- AWS IAM
- Fine grained access control

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AppSync Datasources
- Amazon DynamoDB
- AWS Lambda
- Amazon Elastic Search
- Amazon Aurora
- HTTP services

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AppSync Resolvers
- A resolver must be attached for every operation
- Velocity template language (VTL)
- Takes requests as inputs and outputs a JSON document containing
the instructions to the data source
- VTL allows quite complex operations over the data – loops,
conditions, filters.

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How Appsync works?
Creates a schema

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How Appsync works?
Connect to different
datasources
Creates a schema

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How Appsync works?
Connect to different
datasources
Creates a schema
Updates data in real time
in different devices

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Customer story using Appsync??

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Infrastructure as code
• AWS Cloudformation
• Serverless Framework
• Serverless Framework plugin for AppSync
(https://github.com/sid88in/serverless-appsync-plugin)

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AWS Cloud
Client
AWS
AppSync
AWS
Lambda
Amazon
DynamoDB
VLT mappers
for request
and response
VLT mappers
for request
and response

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How the client uses this?
• AWS Amplify
• Client library for building cloud apps
• More info: https://aws-amplify.github.io/docs/js/api#aws-appsync-
sdk

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Configure the client

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Run a Query

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Best practices when working with AppSync
- Think about how to implement search
- Be careful when doing a lot of HTTP requests
- Use as much VLT resolvers as possible
- Use subscriptions appropriately
- Paginate your large responses

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Q&AMarcia Villalba
AWS Loft in Kyiv
14-18 October
https://aws-loft.provectus.com
Marcia Villalba
@mavi888uy
Practical examples on AppSync and more on
serverless
https://www.youtube.com/foobar_codes

57. © 2019, Amazon Web Services, Inc. or its Affiliates.© 2019, Amazon Web Services, Inc. or its Affiliates.
Thank you!
Marcia Villalba
@mavi888uy
AWS Loft in Kyiv
14-18 October
https://aws-loft.provectus.com
Practical examples on AppSync and more on
serverless
https://www.youtube.com/foobar_codes