System requirements
Functional:
List functional requirements for the system (Ask the chat bot for hints if stuck.)...
User authentication for admin purposes
Occupy/ Release Parking places
Analytics
Parking places optimization Service
Non-Functional:
List non-functional requirements for the system...
availability should be highest 99.999% since parking disruptions can have domino effect on traffic and business.
should be scalable since peek time would have alot of demand
should be secure so it could mitigate the risk of DDOS and other such attacks
performance should be high to give real time free parking spaces
Monitoring to check for unhealthy services
Cost efficient that we don't overwhelm the budget.
Capacity estimation
Estimate the scale of the system you are going to design...
lets take an estimation of medium size and we can increase or decrease services on the basis of demand
let suppose.
in Pakistan there are 25million people , lets consider
10% of them owns a vehicle.
2.5million users
and lets consider 25% of the are Daily active user
that will be 625k users
operations will be read of parking lots
almost similar number will be the sensors who will be using write operations available or unavailable parking lots
2 * 1250k
2500k dailly
for seconds 60*60*24 = 86400 ~ 100000 to simplify
2500000/100000 ~ 25 req per second
25 per second request
if performance of each server is 0.5ms
servers required = 13 servers
Storage capacity
location
boolean 5 ,6 bytes
2500k * 10bytes = 25MB daily
2.5 million * 30*12*5 = 2.5tb for 5years
API design
Define what APIs are expected from the system...
get v1/find_parking?location={coordinates}
respone { locationUrl }
put v1/parking_lot?parkingId={}
request: {
status : available/ unavailable
}
response {
success : true
}
Database design
Defining the system data model early on will clarify how data will flow among different components of the system. Also you could draw an ER diagram using the diagramming tool to enhance your design...
user :
id
username
hashPassword
parkingArea:
id
location
status
sensor:
id
status: active/failed healthcheak
parkingId
High-level design
You should identify enough components that are needed to solve the actual problem from end to end. Also remember to draw a block diagram using the diagramming tool to augment your design. If you are unfamiliar with the tool, you can simply describe your design to the chat bot and ask it to generate a starter diagram for you to modify...
Request flows
Explain how the request flows from end to end in your high level design. Also you could draw a sequence diagram using the diagramming tool to enhance your explanation...
Detailed component design
Dig deeper into 2-3 components and explain in detail how they work. For example, how well does each component scale? Any relevant algorithm or data structure you like to use for a component? Also you could draw a diagram using the diagramming tool to enhance your design...
Trade offs/Tech choices
Explain any trade offs you have made and why you made certain tech choices...
Failure scenarios/bottlenecks
Try to discuss as many failure scenarios/bottlenecks as possible.
Future improvements
What are some future improvements you would make? How would you mitigate the failure scenario(s) you described above?