System requirements

Functional:

List functional requirements for the system (Ask the chat bot for hints if stuck.)...

1. Allow users to acquire a lock
2. Allow users to release a lock
3. Allow users to know that there is already a lock in place
4. Allow fairness of acquisition of lock

Non-Functional:

List non-functional requirements for the system...

1. System should be available
2. Low latency
3. Consistent response to avoid deadlocks

Capacity estimation

Estimate the scale of the system you are going to design...

API design

Define what APIs are expected from the system...

POST - /v1/user/resource/lock

{

user_id:

resource_id:

// acquisition_time:

}

201 created

{

lock_id

}

DELETE v1/user/resource/lock

{

lock_id

}

{

200 OK

}

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...

Table to store lock information on resources

Shard on resource_id

User_id

resource_id

is_lock -yes

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...

1. Client calls locking server POST API - /v1/user/resource/lock to acquire the lock
2. locking server takes the request and publishes to kafka
3. kafka consumer picks it up puts it in a queue and at the same time write to DB and cache.

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...

I will talk about the datamodel and the queue

how lockserver picks up the message and write into DB

client_id

resource_id

expiration_time

Once the message is picked up and is wriiten into the DB with an expiration _time. and it gets pushed into the queue again at the end of the queue.

consumer picks up the next message and checks in the cache if the resource already has a lock with an expiration time in the future.it will not do anything. But if the lock is expired, it will push this message back into the queue and acquire the lock.

It updates the row of the resource_id with this user/client_id and sets a newer expiration time.

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?