Moodboard App

What is Moodboard (Digital pinboard) = ID App by Amo

Suppose you are going on vacation and you created pinboard where you will pin (photos, videos, text)

Requirements

Functional (CRUD)

1. Create. User can create the pinboard
2. Read. User can see the created pinboard
3. Update. User can add/delete/update text/video/image on pinboard
4. Delete. User can delete pinboard

Non-Functional

1. Reliable. Once board created, it should be not autoremove image,text,video on board
2. Latency: No latency in viewing/editing the Moodboard
3. Secure: Board should be visible to friends only

BOE

BW requirements not huge, User can create video(upload), then photo(upload) etc.

System APIs (CRUD)

REST API?
REST API Versioning(v1,v2)

1. Create	2. Read	3. Update	4. Delete
`curl -X POST -H "Content-Type: application/json" -d '{"name": "board_us"}' http://127.0.0.1:8080/v1/board/create -vvv`	`curl -X GET http://127.0.0.1:8080/v1/board/get -vvv`	`curl -X PUT -H "Content-Type: application/json" -d '{"old_name": "board", "new_name": "NewBoard2"}' http://127.0.0.1:8080/v1/board/update -vvv`	`curl -X DELETE -H "Content-Type: application/json" -d '{"old_name": "board_us"}' http://127.0.0.1:8080/v1/board/delete -vvv`
`POST https://url/v1/board/create //url=id.amo.com header { Authorization: {Bearer "API_KEY_TOKEN"}, /Mandatory added by HTTP Start/ Content-len: 0 Host: //Calculated when req is sent UserAgent: Postman Accept: / Accept-Encoding: gzip, deflate, br Connection: Keepalive /Mandatory added by HTTP End/ } body { //JSON //Suppose travelling to US name: us_board }`	`//All boards of a user GET https://url/v1/boards header { Authorization: {Bearer "API_KEY_TOKEN"}, ..other fields.. } body { //JSON "old_name": "Board", "new_name": "NewBoard2" }`	`// Update existing board name PUT http://url/v1/board/update header { Authorization: {Bearer "API_KEY_TOKEN"}, ..other fields.. }`	`// Delete existing board name Delete http://url:8080/v1/board/delete header { Authorization: {Bearer "API_KEY_TOKEN"}, ..other fields.. } body { //JSON "old_name": "Board_to_be_deleted", "new_name": "test" }`

1. Create

2. Read

3. Update

4. Delete


curl -X POST -H "Content-Type: application/json" 
-d '{"name": "board_us"}' http://127.0.0.1:8080/v1/board/create -vvv


curl -X GET http://127.0.0.1:8080/v1/board/get -vvv


curl -X PUT -H "Content-Type: application/json" -d 
'{"old_name": "board", "new_name": "NewBoard2"}' 
http://127.0.0.1:8080/v1/board/update -vvv


curl -X DELETE -H "Content-Type: application/json" 
-d '{"old_name": "board_us"}' 
http://127.0.0.1:8080/v1/board/delete -vvv


POST https://url/v1/board/create   //url=id.amo.com
header {
  Authorization: {Bearer "API_KEY_TOKEN"},

  /*Mandatory added by HTTP Start*/
  Content-len: 0                        
  Host:        //Calculated when req is sent
  UserAgent: Postman
  Accept: */*       
  Accept-Encoding: gzip, deflate, br
  Connection: Keepalive
  /*Mandatory added by HTTP End*/
}
body {  //JSON
  //Suppose travelling to US
  name: us_board
}


//All boards of a user
GET https://url/v1/boards
header {
  Authorization: {Bearer "API_KEY_TOKEN"},
  ..other fields..
}
body {  //JSON
  "old_name": "Board", 
  "new_name": "NewBoard2"
}


// Update existing board name
PUT http://url/v1/board/update
header {
  Authorization: {Bearer "API_KEY_TOKEN"},
  ..other fields..
}


// Delete existing board name
Delete http://url:8080/v1/board/delete
header {
  Authorization: {Bearer "API_KEY_TOKEN"},
  ..other fields..
}
body {  //JSON
  "old_name": "Board_to_be_deleted", 
  "new_name": "test"
}

DB Schema

Graph DB


user Table
| userid(pk) | username | created_at(timestamp) | enabled |

password Table 
| user_id(pk) | password_hash | created_at | expiry_at |

- Photos, Videos will be stored in Object Store
- Friends list, comments would be stored in Graph DB.
 
Photo Table
| photo_id(pk) | photo_url(url on object store) | user_id (fk) | comment_id |

MoodBoard Table
| moodboard_id(pk) | user_id(fk) |

HLD

1. Reading moodboard
2. Updating moodboard (ie upload photo)

1 user

1 Million users

            @startuml
            actor User as u
            box "Data Center"   #Cyan
            participant LoadBalancer as lb
            participant AppServer as as
            queue Kafka as kafka  #LightPink
            participant "Photo\nProcessor" as pa
            participant Diesel as diesel
            database DB as db
            end box
            database "ObjectStore\nAmazon S3" as os  #Brown
            
            u -> lb: HTTP GET moodboard
            lb -> as: HTTP GET moodboard
            as -> diesel: "SELECT * FROM"
            diesel -> db: "SELECT * FROM"
            db -> as: content
            note over as
            Create HTTP Response
            Body(moodboard)
            end note
            as -> u: moodboard
            
            note over u
            moodboards shown
            to user
            end note
            
            note over u
            User selects
            moodboard2 and
            drop photo on
            coordinates (x,y)
            end note
            
            u -> lb: HTTP PUT(Update)\nuserId=1, moodboardId=2\n content=image, location=(x,y)\nphoto url
            u -> lb: photo
            lb -> as: HTTP PUT(Update)\nuserId=1, moodboardId=2\n content=image, location=(x,y)\nphoto url
            lb -> as: photo
            
            note over as
            validate photo:
            - acceptable format(jpg,png)
            - acceptable size
            - not virus
            end note
            
            as -> kafka: photo
            kafka -> pa: photo
            note over pa
            resize, compress
            end note
            
            pa -> os: photo
            pa -> db: Metadata of photo
            note over db
            URLs/
            Thumbnails
            end note
            
            as -> diesel: INSERT INTO\nmoodboard table
            diesel -> db: INSERT INTO\nmoodboard table
            
            as -> u: ACK, Update success
            
            @enduml

Issue	Solution
Single Point of Failure 1 Application Server, 1 DB might fail	Multiple Application Servers. Autoscaling using Helm Chart Multiple Database Replication
Scalabilty Issues	On heavy load in addition to Load Balancing, Sharding would be helpful