Key Value DB (Redis) code feedback

Key Value DB (Redis) code feedback

Think of the feedback below as PR comments on your code. I have reviewed several implementations written by many developers and condensed my common PR comments below. When you implement this keyvaluedb in Go, these are some things you should look into. These will help you evaluate whether your solution is good enough or not.
 
Code formatting and tooling
  • Auto-formatting: Set up your code editor to auto-format using gofmt for consistency.
  • Unit Test Integration: Enable easy one-click execution of unit tests in your IDE. Ensure that unit tests cover the TCP server implementation's critical code paths and error scenarios.
  • Encourage modular design by separating distinct functionalities into well-organized packages.
  • Consider organizing your project into separate command handling (business logic), storage, and networking (handler/adaptor) directories.
TCP Server Implementation
  • TCP Server Design: Consider using Go's built-in net package to implement the TCP server. Ensure that the server listens on a specific port and accepts incoming connections.
  • Concurrency: Implement concurrent handling of incoming client connections. Each client connection should run in its goroutine to ensure concurrent client interactions.
Unit testing
  • Write extensive unit tests for each command to cover different scenarios, including valid inputs, edge cases, and error conditions. Example: Run this keyvaluedb and input the set command with the wrong number of arguments. How does your program behave in that case? Does it fail with a proper error message or panic abruptly? Can you write a unit test for this scenario? What other error scenarios can you think of?
  • Can you identify the test scenarios for the keyvaluedb and refactor the code to use table-driven tests? Did you know you can use the VS Code feature to generate test cases by right-clicking the method name? It will auto-generate table-driven tests for that function.
  • Have you tried testing your program with a large number of keys? (e.g., 10k key-value pairs? Does it work as expected, or does it fail silently? Does it go out of memory (if you try to run it with some memory limits)? How are you load-testing your implementation?
  • Have you written test cases to verify that your TCP server can handle multiple connections simultaneously?
Error handling
  • Implement proper error handling throughout the codebase. Consider using the errors package to create descriptive error messages. Ensure your keyvaluedb program behaves similarly to Redis regarding command input/output, error cases, etc.
  • Implement robust input validation at various levels, such as command parsing and storage operations. This prevents unexpected behavior and enhances the system's reliability.
  • Implement robust error handling for TCP server operations, including connection establishment, data reading, and writing. Provide meaningful error messages to clients when errors occur.
Data Storage and Retrieval
  • Data Structures: Choose appropriate data structures for storing key-value pairs in memory. Consider using Go maps or other data structures that provide efficient key-based retrieval.
  • Be aware of the potential for concurrent access to the storage, especially given that it's shared among multiple clients. This situation could lead to data races, where multiple goroutines access the same data simultaneously without synchronization. To handle this, consider exploring techniques like using read-write locks. These locks allow multiple readers or a single writer to access the data simultaneously while preventing concurrent read-write access.
  • Leveraging the Go tooling to detect data races during development is highly recommended. You can use the go run -race your_program.go command. This will run your program with the race detector enabled, helping you identify and address any data race issues. Ensuring concurrent safety is crucial for the reliability of your application.