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#!/usr/bin/node
/* jshint esnext:true */
"use strict";
/*
* cruncher calculates global_point and player_point for stats.
* It listens to the queue `crunch` and expects a JSON with
* a string that is a `participant.api_id`.
* cruncher will update the sums of points
* and send a notification to web.
*/
const amqp = require("amqplib"),
Promise = require("bluebird"),
fs = Promise.promisifyAll(require("fs")),
winston = require("winston"),
loggly = require("winston-loggly-bulk"),
Seq = require("sequelize"),
sleep = require("sleep-promise");
const RABBITMQ_URI = process.env.RABBITMQ_URI,
DATABASE_URI = process.env.DATABASE_URI,
LOGGLY_TOKEN = process.env.LOGGLY_TOKEN,
// size of connection pool
MAXCONNS = parseInt(process.env.MAXCONNS) || 3,
// number of participants to calculate at once
BATCHSIZE = parseInt(process.env.BATCHSIZE) || 1000,
LOAD_TIMEOUT = parseInt(process.env.LOAD_TIMEOUT) || 5; // s
const logger = new (winston.Logger)({
transports: [
new (winston.transports.Console)({
timestamp: true,
colorize: true
})
]
});
// loggly integration
if (LOGGLY_TOKEN)
logger.add(winston.transports.Loggly, {
inputToken: LOGGLY_TOKEN,
subdomain: "kvahuja",
tags: ["backend", "cruncher"],
json: true
});
(async () => {
let seq, rabbit, ch;
// connect to rabbit & db
while (true) {
try {
seq = new Seq(DATABASE_URI, {
logging: false,
max: MAXCONNS
}),
rabbit = await amqp.connect(RABBITMQ_URI, { heartbeat: 320 }),
ch = await rabbit.createChannel();
await ch.assertQueue("crunch", {durable: true});
break;
} catch (err) {
logger.error("Error connecting", err);
await sleep(5000);
}
}
// load update SQL scripts; scripts use sequelize replacements
// for the `participant_api_id` array
const player_script = fs.readFileSync("crunch_player.sql", "utf8"),
global_script = fs.readFileSync("crunch_global.sql", "utf8");
// fill a buffer and execute an SQL on a bigger (> 1o) batch
const participants_player = new Set(),
participants_global = new Set(),
// store the msgs that should be ACKed
buffer = new Set();
let timeout = undefined;
// set maximum allowed number of unacked msgs
await ch.prefetch(BATCHSIZE);
ch.consume("crunch", (msg) => {
const api_id = msg.content.toString();
if (msg.properties.type == "global")
participants_global.add(api_id);
if (msg.properties.type == "player")
participants_player.add(api_id);
buffer.add(msg);
if (timeout == undefined) timeout = setTimeout(crunch, LOAD_TIMEOUT*1000);
if (buffer.size >= BATCHSIZE) crunch();
}, { noAck: false });
// execute the scripts
async function crunch() {
const profiler = logger.startTimer();
logger.info("crunching");
// prevent async issues
const api_ids_player = [...participants_player],
api_ids_global = [...participants_global],
msgs = new Set(buffer);
participants_global.clear();
participants_player.clear();
buffer.clear();
clearTimeout(timeout);
timeout = undefined;
if (api_ids_global.length > 0)
await seq.query(global_script, {
replacements: { participant_api_ids: api_ids_global },
type: seq.QueryTypes.UPSERT
});
if (api_ids_player.length > 0)
await seq.query(player_script, {
replacements: { participant_api_ids: api_ids_player },
type: seq.QueryTypes.UPSERT
});
// ack
await Promise.map(msgs, async (m) => await ch.ack(m));
// notify web
// TODO notify for player too
await ch.publish("amq.topic", "global", new Buffer("points_update"));
profiler.done("crunched", { size: msgs.size });
}
})();
process.on("unhandledRejection", function(reason, promise) {
logger.error(reason);
});
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