This is an implementation of a distributed system using the Raft consensus algorithm. The library used for the implementation is gRPC and the programming language used is C++.
The code defines a node_details struct to represent each node in the distributed system. The struct contains the node_id, node_status, term_no, and a static hasVoted boolean to indicate if the node has already voted in the current term.
The server side of the system is implemented using the RaftService class, which extends dummyRaftService::Service. This class implements two methods - send_message and vote_request. Both methods increment the TERM_NO global variable to indicate that a new term has begun.
The send_message method receives a MessageContent object from a client and prints the message to the console. It also appends the message to a log file. The method then creates a MessageReply object and increases its term_no attribute before returning the object.
The vote_request method receives a VoteRequest object from a client and prints the message to the console. It also appends the message to a log file. If the node has not yet voted in the current term, it creates a VoteReply object and sets its vote_granted attribute to true. It then sets the hasVoted attribute of the node_details struct to true and returns the VoteReply object. If the node has already voted in the current term, it creates a VoteReply object and sets its vote_granted attribute to false before returning the object.
The main function of the code reads in a configuration file containing the addresses of all the nodes in the system. It then creates a node_details object for each node and initializes its attributes. It also creates a RaftService object and starts a server on each node. The main function then enters a loop where it listens for user input. If a user enters a message, it sends the message to all other nodes in the system using the send_message method. If a user enters a vote request, it sends the request to all other nodes in the system using the vote_request method.
- Install gRPC by following their offical documentation.
- Clone this repo in grpc/examples/cpp/
- Open the given directory in terminal and run the following commands:
- $ mkdir -p cmake/build
- $ pushd cmake/build
- $ cmake -DCMAKE_PREFIX_PATH=$MY_INSTALL_DIR ../..
- $ make -j 4
- After running the commands, you can execute the node.cc file by typing in the terminal: $ ./node 4001 Follower term_no where term_no can be any number and 4001 is the port number Note that you are supposed to run this executable in multiple terminals (max 4) in order to simulate the distributed environment. You can only the following port numbers: 4001, 4002, 4003, 4004.