About

Distributed key value store built on top of a Raft implementation with eio from scratch. I started working on this to practice OCaml. I'll stop working on it as soon as I lose interest.

Not every module uses eio because I started without it.

Running locally

Start the replicas.

# Terminal 1
ID=0 dune exec server

# Terminal 2
ID=1 dune exec server

# Terminal 3
ID=2 dune exec server

Sends requests

# Replica 1
curl -XPOST http://localhost:8100 -d '{"key": "a", "value": "1"}'
curl http://localhost:8100/key

# Replica 2
curl -XPOST http://localhost:8101 -d '{"key": "a", "value": "1"}'
curl http://localhost:8101/key

# Replica 3
curl -XPOST http://localhost:8102 -d '{"key": "a", "value": "1"}'
curl http://localhost:8102/key

TODO

• After an user request is received and replicated to a quorum, a response must be sent to the client.
• Check that the replica append one entry to its log when it becomes a leader
• Use eio in the network and storage layer
• Check that data is correctly stored in the state file (look at the file contents and ensure there's nothing weird stored in there)
• Heartbeat timeout handling. Reset timeout
• Persist last applied index to avoid reapplying the whole log
• Handle exceptions
• Stop using lists
• Remove completed todos
• Clean up inflight requests, add request queue