rusty-cache

Distributed cache in Rust

This is a learning project, and it will never become anything production ready. It's almost first Rust code I'm writing in my life.

Planned:

• distributed cache
• multiple servers
• no replication
• each can accept values and pass them to correct node

What should be implemented:

• accepting data from TCP messages
• setting TTL on set
• background process to evict keys after TTL
• additional data types

How would functionality be distributed

• server
  • accepts lists of other servers on start
  • knows which server is responsible for which key
  • can act as a proxy to answer any client request
• client
  • can connect to any server in cluster and send commands to it

Details - server addition

• server 1 (leader) comes up, only server in cluster, handles all requests
  • it has server channel and client channel
  • server has hashmap bucket_id (16) -> list of keys
• each server has a map bucket_id -> tcp connections
• server 2 comes up, connects to server 1, sends join_cluster request
• server 1 updates bucket_id -> server map, assigns buckets to server 2
  • need to update other servers with fresh cluster_state

Details - client-server interaction

• client can join any server in the cluster
• when client sends request, server
  • checks if it can serve the request
  • if it can't, it acts as a proxy, sending request to server 2, and returning response
• this makes client totally oblivious to state of cluster and interactions with it

What can be added further

• monitoring
• replication (secondary node stores keys from next bucket, can answer requests)
• additional data types
• bloom filters for key existence check