goraft

A minimal implementation of Raft in Go. Demo video.

NOT FOR PRODUCTION USE.

Things that are missing:

Client serial identifier for each message (maybe the most obvious missing function/actual bug)
- Search for "session" in Diego Ongaro's thesis for more details.
Snapshotting/checkpointing and associated state transfer
Configuration change protocol
Rigged up to Jepsen
Surely much else

Stress

Not particularly aggressive yet but does basic correctness and stress testing.

Read more about the details of what it tests in the README.

$ cd cmd/stress
$ go run main.go util.go

With the go-deadlock package turned off and the default sync package on, I get throughput of around 20k-40k entries/second with this stress test.

Distributed Key-Value Store API

Try out the builtin distributed key-value API.

$ cd cmd/kvapi && go build
$ rm *.dat

Terminal 1

$ ./kvapi --node 1 --http :2021 --cluster "0,:3030;1,:3031;2,:3032"

Terminal 2

$ ./kvapi --node 1 --http :2021 --cluster "0,:3030;1,:3031;2,:3032"

Terminal 3

$ ./kvapi --node 2 --http :2021 --cluster "0,:3030;1,:3031;2,:3032"

Terminal 4

Remember that requests will go through the leader (except for if we turn that off in the /get request). So you'll have to try sending a message to each server until you find the leader.

To set a key:

$ curl http://localhost:2020/set?key=y&value=hello

To get a key:

$ curl http://localhost:2020/get\?key\=y

References

In Search of an Understandable Consensus Algorithm: The Raft paper.
raft.tla: Diego Ongaro's TLA+ spec for Raft.
Jon Gjengset's Students' Guide to Raft
Jack Vanlightly's Detecting Bugs in Data Infrastructure using Formal Methods (TLA+ Series Part 1): An intro to TLA+.

And useful implementations I looked at for inspiration and clarity.

Hashicorp's Raft implementation in Go: Although it's often quite complicated to learn from since it actually is intended for production.
Eli Bendersky's Raft implementation in Go: Although it gets confusing because it uses negative numbers for terms whereas the paper does not.
Jing Yang's Raft implementation in Rust.

aocsa / goraft