Algorep project

Authors

• Hugo BOIS
• Nathan CABASSO
• Jeremy CROISET
• Ferdinand MOM
• Erwan VIVIEN

Implementation of RAFT consensus algorithm in Rust. We followed the paper.
This is a school project for the course Algorep at EPITA (School of Engineering and Computer Science).

Running the project

To run the project, you need to have cargo installed.
Then, you can run the project by running the following command in the root directory of the project: cargo run --release.

You can interract with servers by using the following commands:

• REPL <server_id> <command> with <server_id> in the range of [0; node_count - 1] and <command> being one of the following:

  • CRASH: Crash the server (ignores messages)
  • START: Allows the clients to send messages to the servers
  • SHUTDOWN: Shutdown the server (stops the server, server is no longer reachable)
  • RECOVERY: Reload the data from the disk and remove volatile state
  • TIMEOUT: Force the server to start an election
  • DISPLAY: Display the state of the server

You can act as a client by using the following commands:

• <command> [content] with <command> being one of the following:

  • LOAD <filename>: Creates a file in the store
  • GET <UID>: Get the content of the file in the store
  • DELETE <UID>: Delete the key-value pair associated with the key
  • APPEND <key> [message]: Append the message to the content of the file in the store with a new line

Note: The client does not automaticaly retry to send a message if it fails. You need to resend the message manually. This is the design we chose for the client.

Server configuration

The configuration file is a RON file (Rusty Object Notation) that can be found in the config directory and is named config.ron.
What can be configured is the following:

• node_count: the number of nodes(servers) in the cluster
• election_timeout: a range of ConfigTime enum (see config.rs for more details). This range is what is used by servers to generated a random timer.
• client_count: the number of clients that will be spawned by the main.rs file

Running the tests

To run the tests, you need to have cargo installed.
Then, you can run the tests by running the following command in the root directory of the project: cargo test.

The following tests are implemented:

• should_accept_vote: Checks if a server accepts a vote request from another server if valid
• should_receive_election: Checks that a server timeouts and starts an election in the beginning of the simulation
• should_retry_election: Checks that a server timeouts and starts an election. If we reply with an AppendEntries message with a higher term, the first server should accept it
• should_elect_first: If two servers do not have the same election timeout, the first one to timeout should be elected
• setup_server_client_no_recv: Checks that a server can be setup and a client can be setup. If no interaction the client should not receive any message
• client_send_request: Checks that a client can send a request to a server and that the server can receive it
• client_server_should_receive_entry: Checks that a client can append an entry to a server and an other server receives the entry followed by empty entries.
• should_timeout: Checks that a server timeouts if it does not receive correct messages. e.g. if a server receives an AppendEntries message with a lower term, it should not reset it's timer
• should_handle_append_entries: Checks that a server can handle an AppendEntries message and reply with the correct message. This is the end-to-end test. A client generates requests to create/modify fiels, the server replicates them and applies them to the state machine. After that, if a client GET a file, it should receive the correct value.