Raft implements Raft. Raft servers use cluster service to send and receive messages. This project currently includes only election component and not log messages. The server term and voted for information is persisted on stable storage.

Raft servers use LevelDB for log storage. LevelDB installation should be done prior to using this package. This package uses [Levigo] (https://github.com/jmhodges/levigo). See Levigo's README for building LevelDB.

$ go get github.com/pkhadilkar/raft
$ # cd into directory containing raft/raftImpl
$ go test

If you want to create logs and stable directories at different path, please change paths RaftConfig object in test files. Please see installation instructions for cluster as cluster uses ZeroMQ libs and zmq4 by pebbe.

• Message scale test (msgScale_test.go): This test sends 1000 messages to leader and verifies that a follower receives all the entries. Note that each of the message is doing a disk write and all Raft servers run locally.

• Leader Partition and Rejoining (leaderSeparation_test.go) : This test case first waits for Raft to elect a leader. It then simulates leader crash by ignoring all messages to/from leader and checks that the remaining servers elect a new leader. It then re-introduces old leader into the cluster and checks that the old leader reverts back to the follower.

• Majority Minority Partition (part_test.go) : This test case first waits for Raft to elect a leader. It then creates a minority network partition that contains leader and a follower and checks that the servers in majority partition elect a new leader.

Configuration file contains configuration for both cluster and Raft leader election. Please see cluster for cluster specific fields. Raft configuration include TimeoutInMillis which is base timeout for election and HbTimeoutInMillis - timeout to send periodic heart beats. Raft recommends that general relation between timeouts should be "msg_send_time << election_timeout". Also heartbeat time should be much less than election timeout to avoid frequent elections. LogDirectoryPath contains the path to directory used by servers to create log files. Please ensure that this directory is created before using raft-leader-elect. Each server creates a file with name <server's pid>.log in this directory. RaftLogDirectoryPath is the path of the directory that Raft servers should use to create LevelDB database key value store stable storage.

Please see raftImpl/simple_test.go test case which serves as a simple example of use of raft.