Coinbase DevOps Engineer System Design Questions

With numerous microservices, it’s crucial for Coinbase to have a robust service health monitoring system to ensure uptime and reliability.
Problem Statement: Design a ServiceHealthMonitor class that can check the health of services and report their status. This monitor should allow dynamic addition of services and periodic health checks.
Method Signatures:
- def add_service(name: str, check_func: Callable[[], bool]) -> None: - Adds a service to be monitored along with its health check function.
- def check_health() -> Dict[str, bool]: - Checks the health of all services and returns a dictionary mapping service names to health status.
- def report_status() -> None: - Reports the health status of the services, ideally logging or sending alerts for any down services.Example 1:
Input: add_service('auth_service', lambda: True)
Output: None
Explanation: Adds the auth_service with a successful health check.Example 2:
Input: check_health()
Output: {'auth_service': True}
Explanation: Returns the health status of the services.Constraints:
- 1 <= name.length <= 50
- The number of services monitored will not exceed 100.

To improve performance and reduce latency, Coinbase needs a sophisticated caching mechanism for frequently accessed API responses.
Problem Statement: Design and implement an LRUCache class that supports the following operations: get and put. The operations should be efficient enough to meet the demands of high-frequency API access.
Method Signatures:
- def get(key: int) -> int: - Returns the value of the key if the key exists, otherwise returns -1.
- def put(key: int, value: int) -> None: - Updates the value of the key if the key exists and if it doesn't, adds the key-value pair to the cache. When the cache reaches its capacity, it should invalidate the least recently used item before inserting a new item.Example 1:
Input: put(1, 1)
Output: None
Explanation: Cache updated with key 1 and value 1.Example 2:
Input: get(1)
Output: 1
Explanation: Returns the cached value 1 for key 1.Constraints:
- capacity must be a positive integer.
- The number of calls to get and put will not exceed 10000.
- 1 <= key, value <= 1000.