System requirements
Functional:
- create tiny url and redirect from tiny url to general url
- allow user to customiz tiny url
- delete tiny url
- update tiny url
- epxire date
Non-Functional:
List non-functional requirements for the system...
- high available
- scable when usages increase
- low latency to provide smooth experience
- high reliable -> not lose user data
- read heavily system
Capacity estimation
- Data storage
- 1M tiny url generated
- Original url size: 100 char. 200 byte
- tiny url: 30 char -> 60 byte
- each url: 300 bytes
- all storage ->
- 300 * 1M = 300 MB data storage
- TPS
- read - write ratio = 5:1
- write
- DAU: 1M
- 1M read per day -> (100K second/day) = 10 TPS
- write 2TPS:
- traffic distributed evenly
- Bandwidth
API design
Define what APIs are expected from the system...
POST
/v1/createTinyURL
(user_token, original_url, customized_url(optional), expire_date)
GET
/v1/redirectURL
(user_token, tiny_url)
DELETE
/v1/deleteURL
(user_token, tiny_url)
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...
no relation needed
recommend NoSQL database example (dynamoDB)
primary key
- tiny url
secondary KEY
- original url
- expiry date
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...
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...
- how to generate tiny url
- UUID generate unique tiny url. Encode, shorten
- MD5, SHA256 hash function
- key generator
- how to handle expired url
- lazy cleanup
- Whenever a user tries to access an expired link, we can delete the link and return an error to the user.
- A separate cleanup service can run periodically to remove expired links from our storage and cache. This service should be very lightweight and can
- how to do redirect
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?
- cache