Tutorial developed for FEUP students at "Semana de Informática" conference on the 1st of November 2018 by Pedro Costa.

Files - Download All

• bucketpolicypermissions.json
• convertoaudio.py
• getposts.py
• index.html
• lambdapolicy.json
• mappings.json
• newposts.py
• sample.json

Architecture

• Two S3 (Simple Storage Service) Buckets
  • - Storing the static website
  • - Storing the MP3 files
• Gateway - Connects the HTTP Requests to lambda functions
• DynamoDB - No-SQL database for storing the notes
• Polly - Amazon service to turn text to voice
• Lambda functions
  • - GetPosts - Searchs the DB for the posts
  • - NewPost - Adds new post to DB and creates notification for turning that text into voice
  • - ConvertToAudio - Retrieves text from DB, converts it to audio, storages the file on S3 and updates DB post record
• SNS (Simple Notification System) - Decouples the architecture, separating the new post function from the convert to audio

Steps

• Go to dynamo db

  • Create dynamoDB table
    • Table Name: posts
    • Primary key: id
    • Click create

• Go to S3

  • Create s3 bucket
    • Bucket name: sinf-[your_name]
    • Click “Create” button
    • Click on the created bucket
    • Go to properties tab
    • Click on “Static website hosting”
    • Select “Use this bucket to host a website” and type “index.html” and then save
  • Create another bucket
    • Bucket name: sinf-mp3-[your_name]
    • Click “Create” button

• Go to IAM (Identity Access Management)

  • Go to “Roles” on the left side panel
    • Click create a Role
      • Under “Choose the services that will use this role”, click “Lambda”
      • Click “Next: Permissions”
      • Click “Create policy”
      • Click on the “JSON” tab
      • Copy the code from lambdapolicy.json to the editor
      • Click “Review Policy”
      • Write “myLambdaPollyPolicy” in the name and descriptions
      • Click “Create”

• Go to IAM (Identity Access Management)

  • Go to “Roles” on the left side panel
    • Click create a Role
      • Under “Choose the services that will use this role”, click “Lambda”
      • Search for the policy “myLambdaPollyPolicy”
      • Select that policy
      • CLick next
      • Write “MyLambdaRole” in the role name and description

• Go to S3

  • Click on the bucket sinf-[your_name]
  • Go to “Permissions” tab
  • Click on “Bucket Policy”
  • Copy the code from bucketpolicypermissions.json to the editor
  • Change “BUCKET_NAME” in your code to your bucket name
  • Click “Save”

• Go to SNS (Simple Notification Service)

  • Create a topic
    • Write “new_posts” on the Topic name
    • Write “SNSpolly” on the Display name
    • Click “Create topic”
    • Copy the “Topic ARN” to here

• Go to Lambda

  • Click “Create function”
    • Write “PostReader_NewPosts” in the name field
    • Select Python 2.7 on Runtime
    • On “Role” select "Choose an existing role
    • On “Existing role” select “myLambdaPollyRole”
    • Click “Create function”
    • Copy the code from newposts.py to the editor
    • Click “Save”
    • Scroll down to Environment variables
      • Add variable “DB_TABLE_NAME” with value “posts”
      • Add variable “SNS_TOPIC” with the preivous saved Topic ARN
    • Scroll down to description
      • Write: “This function inserts data into DynamoDB”
    • Scroll up and hit Save
  • Click on test
    • Select “Create new test event”
    • Copy the code from sample.json to the editor
    • Hit “Create”
    • Click on “Test”

• Go to Lambda

  • Click “Create Function”
    • Write "PostReader_ConvertToAudio
    • Select Python 2.7 on Runtime
    • On “Role” select "Choose an existing role
    • On “Existing role” select “myLambdaPollyRole”
    • Click “Create function”
    • Copy the code from convertoaudio.py to the editor
    • Click “Save”
    • Scroll down to Environment variables
      • Add variable “DB_TABLE_NAME” with value “posts”
      • Add variable “BUCKET_NAME” with the name of the bucket “sinf-mp3-[your_name]”
    • Scroll down to description
      • Write: “This function generates our MP3s ans stores them in S3”
      • Change the timeout to 5min (max duration is now 15min)
    • Scroll up and hit Save
    • On the designer scroll down untill SNS and click
    • Click on the SNS trigger
    • Select the SNS topic “new_posts”

• Go to the top

  • Click on functions
  • Click on “Create new function”
    • Write “PostReader_GetPosts” on function name
    • Select Python 2.7 on Runtime
    • On “Role” select "Choose an existing role
    • On “Existing role” select “myLambdaPollyRole”
    • Click “Create function”
    • Copy the code from getposts.py to the editor
    • Click “Save”
    • Scroll down to Environment variables
      • Add variable “DB_TABLE_NAME” with value “posts”
    • Scroll down to description
      • Write: “This function retrieves my posts”
    • Scroll up and hit Save

• Go to API Gateway

  • Click “Create API”
  • Write “PostReaderAPI” on the API name field
  • Write “My API for Polly” on the API description field
  • Click on “Create API”
  • Click on “Actions”
    • Select “Create Method”
    • Select “GET”
    • In “Lambda Funcion” filerd type GetPosts and select “PostReader_GetPosts”
    • Hit “Save”
  • Click on “Actions”
    • Select “Create Method”
    • Select “POST”
    • In “Lambda Funcion” filerd type NewPost and select “PostReader_NewPost”
    • Hit “Save”
  • Click on “Actions”
    • Select “Enable CORS”
    • Click "Enable CORS and replace existing CORS headers
    • Click “Yes”
  • Click on “GET”
    • Click on "Method Request
    • Select “URL Query String Parameters”
      • Add “postsId”
  • Click on “GET”
    • Select “Body Mapping Templates”
    • Select “When there are no templates defined (recommended)”
    • Click “Add mapping template” and type “application/json”
    • Click on the right arrow
    • Click on “application/json”
    • Copy the code from mappings.json to the editor and click “Save”
  • Click on /
    • Actions and Deploy API
    • On Deployment stage select “New Stage” and write prod on all fields
    • Copy the “Invoke Url”

• Go to index.html and replace “YOUR-API-GATEWAY-HERE” with the Invoke Url

• Go to S3

  • Select the sinf-[your_name] bucket
  • Click on Upload button and the “Add files” and select the index.html and hit “Upload”
  • Click on index.html and copy the Link in the button to the url bar