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'use strict';
var async = require('async');
var _ = require('lodash');
var EventEmitter = require('events').EventEmitter;
function LimitedQueue(worker) {
var base = new EventEmitter();
var maxQueueLength = 100000;
var queueClearingThreshold = 0.8;
var throwLogsAway = false;
var joiners = []; // List of callbacks to call when we're empty
var queue = async.cargo(function (s, callback) {
var queueLowerThreshold = (maxQueueLength * queueClearingThreshold);
if (throwLogsAway && queue.length() < queueLowerThreshold) {
var notification = {
'name':'rfs',
'time':new Date(Date.now()).toISOString(),
'event': 'desaturated',
'message': 'Write queue clearing, allowing new log events',
'v':0
};
var inplace = _.extend(
{},
{immediatelog: false},
notification
);
queue.push(JSON.stringify(inplace) + '\n');
var immediate = _.extend(
{},
{immediatelog: true},
notification
);
queue.unshift(JSON.stringify(immediate) + '\n');
console.log(notification.message);
throwLogsAway = false;
base.emit('caughtup');
}
worker(s, callback);
}, 2000);
function push(s) {
if (!throwLogsAway) {
if (queue.length() > maxQueueLength) {
var notification = {
'name':'rfs',
'time':new Date(Date.now()).toISOString(),
'event': 'saturated',
'message': 'Write queue saturated, stopping logging',
'v':0
};
var inplace = _.extend(
{},
{immediatelog: false},
notification
);
queue.push(JSON.stringify(inplace) + '\n');
var immediate = _.extend(
{},
{immediatelog: true},
notification
);
queue.unshift(JSON.stringify(immediate) + '\n');
console.log(notification.message);
throwLogsAway = true;
base.emit('losingdata');
} else {
queue.push(s);
}
}
return queue.length();
}
queue.drain = function () {
if (throwLogsAway) {
var notification = {
'name':'rfs',
'time':new Date(Date.now()).toISOString(),
'event': 'desaturated',
'message': 'Write queue cleared, allowing new log events',
'v':0
};
var message = _.extend({}, {immediatelog: false}, notification);
queue.push(JSON.stringify(message) + '\n');
console.log(notification.message);
throwLogsAway = false;
base.emit('caughtup');
}
if (joiners.length > 0) {
for (var i = 0; i < joiners.length; i += 1) {
joiners[i]();
}
joiners = [];
}
}
function isEmpty() {
return queue.length() === 0;
}
function paused() {
return queue.paused;
}
function join(cb) {
if (queue.length() === 0) {
cb();
} else {
joiners.push(cb);
}
}
return _.extend({}, {
push: push,
paused: paused,
pause: queue.pause,
resume: queue.resume,
unshift: queue.unshift,
join: join,
isEmpty: isEmpty,
length: queue.length
}, base);
}
module.exports = LimitedQueue;
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