nodeway-raft/lib/client.js

It is an implementation of the Raft consensus algorithm in Nodeway.

'use strict';

var sequenceNum = 0;  // FIFO scheduling algorithm used
var clientStack = []; // client request stack

function isOwner(entry) {
    return clientStack.length && clientStack[0].serverId===entry.serverId;
}

function push(args, cb) {
    args.sequenceNum = ++sequenceNum;
    clientStack.push({
        serverId: args.serverId,
        sequenceNum: args.sequenceNum,
        callback: cb
    });
}

function cb(entry, err, response) {
    while(isOwner(entry) && clientStack[0].sequenceNum<=entry.sequenceNum) {
        let request = clientStack.shift();
        if (request.sequenceNum===entry.sequenceNum) {
            request.callback(err, response);
            break;
        }
        request.callback(new Error('SESSION_EXPIRED'));
    }
}

module.exports = {
    isOwner,
    push,
    cb
};