/database-api-for-trivia-app

Primary LanguageJavaScript

Serverless REST API

This is a RESTful Web Services allowing you to create, list, get, update and delete Players for a trivia app. DynamoDB is used to store the data. This is just an example and of course you could use any data storage as a backend.

Structure

This service has a separate directory for all the player operations. For each operation exactly one file exists e.g. players/delete.js. In each of these files there is exactly one function which is directly attached to module.exports.

The idea behind the players directory is that in case you want to create a service containing multiple resources e.g. games, questions, comments you could do so in the same service. While this is certainly possible you might consider creating a separate service for each resource. It depends on the use-case and your preference.

Setup

npm install

Deploy

In order to deploy the endpoint simply run

serverless deploy

The expected result should be similar to:

Serverless: Packaging service…
Serverless: Uploading CloudFormation file to S3…
Serverless: Uploading service .zip file to S3…
Serverless: Updating Stack…
Serverless: Checking Stack update progress…
Serverless: Stack update finished…

Service Information
service: serverless-rest-api-with-dynamodb
stage: dev
region: us-east-1
api keys:
  None
endpoints:
  POST - https://45wf34z5yf.execute-api.us-east-1.amazonaws.com/dev/players
  GET - https://45wf34z5yf.execute-api.us-east-1.amazonaws.com/dev/players
  GET - https://45wf34z5yf.execute-api.us-east-1.amazonaws.com/dev/players/{id}
  PUT - https://45wf34z5yf.execute-api.us-east-1.amazonaws.com/dev/players/{id}
  DELETE - https://45wf34z5yf.execute-api.us-east-1.amazonaws.com/dev/players/{id}
functions:
  create: trivia-service-dev-create
  list: trivia-service-dev-list
  get: trivia-service-dev-get
  update: trivia-service-dev-update
  delete: trivia-service-dev-delete

Usage

You can create, retrieve, update, or delete todos with the following commands:

Create a Player

curl -X POST --url "https://XXXXXXX.execute-api.us-east-2.amazonaws.com/dev/players/Korey Boone" --data '{score": 1}'

Example Result:

{"createdAt":1564759441508,"score":3,"id":"Korey Boone","updatedAt":1564760589253}%

List all Players

curl https://XXXXXXX.execute-api.us-east-2.amazonaws.com/dev/players

Example output:

[{"score":0,"createdAt":1564775446831,"id":"tommy","updatedAt":1564775446831},{"score":0,"createdAt":1564776181202,"id":"kduen","updatedAt":1564776181202},{"createdAt":1564759441508,"score":3,"id":"Korey Boone","updatedAt":1564760589253},{"createdAt":1564764146906,"score":77,"id":"dana","updatedAt":1564767168452},{"score":0,"createdAt":1564776042757,"id":"Justin","updatedAt":1564776042757},{"score":0,"createdAt":1564776011612,"id":"Aaron","updatedAt":1564776011612},{"score":0,"createdAt":1564767876710,"id":"Phil","updatedAt":1564767876710},{"score":0,"createdAt":1564775935833,"id":"Hope","updatedAt":1564775935833},{"score":0,"createdAt":1564775972391,"id":"Alex","updatedAt":1564775972391}]%

Get one Player

# Replace the <id> part with a real id from your players table
curl https://XXXXXXX.execute-api.us-east-2.amazonaws.com/dev/players/<id>

Example Result:

{"score":0,"createdAt":1564775446831,"id":"tommy","updatedAt":1564775446831}%

Update a Player

# Replace the <id> part with a real id from your palyers table
curl -X PUT --url "https://XXXXXXXX.execute-api.us-east-2.amazonaws.com/dev/players/<id>" --data '{"score": 3}'

Example Result:

{"createdAt":1564759441508,"score":3,"id":"Korey Boone","updatedAt":1564760589253}%

Delete a Player

# Replace the <id> part with a real id from your todos table
curl -X DELETE https://XXXXXXX.execute-api.us-east-1.amazonaws.com/dev/todos/<id>

No output

Scaling

AWS Lambda

By default, AWS Lambda limits the total concurrent executions across all functions within a given region to 100. The default limit is a safety limit that protects you from costs due to potential runaway or recursive functions during initial development and testing. To increase this limit above the default, follow the steps in To request a limit increase for concurrent executions.

DynamoDB

When you create a table, you specify how much provisioned throughput capacity you want to reserve for reads and writes. DynamoDB will reserve the necessary resources to meet your throughput needs while ensuring consistent, low-latency performance. You can change the provisioned throughput and increasing or decreasing capacity as needed.

This is can be done via settings in the serverless.yml.

  ProvisionedThroughput:
    ReadCapacityUnits: 1
    WriteCapacityUnits: 1

In case you expect a lot of traffic fluctuation we recommend to checkout this guide on how to auto scale DynamoDB https://aws.amazon.com/blogs/aws/auto-scale-dynamodb-with-dynamic-dynamodb/