level-party-hyper/test/election.js

open a leveldb handle multiple times

var test = require('tape');
var level = require('../');
var path = require('path');
var os = require('os');
var tmpdir = require('osenv').tmpdir();
var datadir = path.join(tmpdir, 'level-party-' + Math.random());

test('failover election party', function (t) {
    var keys = [ 'a', 'b', 'c', 'e', 'f', 'g' ];
    var len = keys.length;
    t.plan(len * (len + 1) / 2);
    var pending = keys.length;
    var handles = {};
    
    keys.forEach(function (key) {
        var h = open(key);
        h.on('open', function () {
            if (--pending === 0) spinDown();
        });
    });
    
    function open (key) {
        var h = handles[key] = level(datadir, { encoding: 'json' });
        return h;
    }
    
    function spinDown () {
        var alive = keys.slice();
        (function next () {
            if (alive.length === 0) return;
            
            check(alive, function () {
                var key = alive.shift();
                handles[key].close();
                next();
            });
        })();
    }
    
    function check (keys, cb) {
        var pending = keys.length;
        if (pending === 0) return cb();
        for (var i = 0; i < keys.length; i++) (function (a, b) {
            var value = Math.random();
            handles[a].put(a, value, function (err) {
                if (err) t.fail(err);
                handles[b].get(a, function (err, x) {
                    if (err) t.fail(err);
                    t.equal(x, value);
                    if (--pending === 0) cb();
                });
            });
        })(keys[i], keys[(i+1) % keys.length]);
    }
});