gristlabs_grist-core/app/server/lib/ServerMetrics.js

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const _ = require('underscore');
const net = require('net');
const Promise = require('bluebird');
const log = require('./log');
const MetricCollector = require('app/common/MetricCollector');
const metricConfig = require('app/common/metricConfig');
const shutdown = require('./shutdown');
const version = require('app/common/version');
const crypto = require('crypto');
// Grist Metrics EC2 instance host and port
const host = 'metrics.getgrist.com';
const port = '2023'; // Plain-text port of carbon-aggregator
// Global reference to an instance of this class established in the constuctor.
var globalServerMetrics = null;
/**
* Server-facing class for initializing server metrics collection.
* Establishes interval attempts to push measured server metrics to the prometheus PushGateway
* on creation.
* @param {Object} user - Instance of User.js server class, which contains config settings.
*/
function ServerMetrics() {
MetricCollector.call(this);
this.socket = null;
// Randomly generated id to differentiate between metrics from this server and others.
this.serverId = crypto.randomBytes(8).toString('hex');
this.serverMetrics = this.initMetricTools(metricConfig.serverMetrics);
this.clientNames = null;
this.enabled = false;
// Produce the prefix string for all metrics.
// NOTE: If grist-rt is used instead of grist-raw for some metrics, this must be changed.
let versionStr = version.version.replace(/\W/g, '-');
let channelStr = version.channel.replace(/\W/g, '-');
this._prefix = `grist-raw.instance.${channelStr}.${versionStr}`;
globalServerMetrics = this;
// This will not send metrics when they are disabled since there is a check in pushMetrics.
shutdown.addCleanupHandler(null, () => this.attemptPush());
}
_.extend(ServerMetrics.prototype, MetricCollector.prototype);
/**
* Checks the given preferences object from the user configuration and starts pushing metrics
* to carbon if metrics are enabled. Otherwise, ends the socket connection if there is one.
*/
ServerMetrics.prototype.handlePreferences = function(config) {
config = config || {};
this.enabled = config.enableMetrics;
Promise.resolve(this.enabled && this._connectSocket())
.then(() => {
if (this.enabled) {
this._push = setTimeout(() => this.attemptPush(), metricConfig.SERVER_PUSH_INTERVAL);
} else if (this.socket) {
this.socket.end();
}
});
};
ServerMetrics.prototype.disable = function() {
this.enabled = false;
if (this._push) {
clearTimeout(this._push);
this._push = null;
}
if (this._collect) {
clearTimeout(this._collect);
this._collect = null;
}
}
/**
* Returns a promise for a socket connection to the Carbon metrics collection server.
* The promise will not fail because of connection errors, rather it will be continuously
* re-evaluated until it connects. The retry rate is specified in metricConfig.js
*/
ServerMetrics.prototype._connectSocket = function() {
if (!this.enabled) { return Promise.resolve(); }
var socket = null;
log.info('Attempting connection to Carbon metrics server');
return new Promise((resolve, reject) => {
socket = net.connect({host: host, port: port}, () => {
log.info('Connected to Carbon metrics server');
this.socket = socket;
resolve();
});
socket.setEncoding('utf8');
socket.on('error', err => {
log.warn('Carbon metrics connection error: %s', err);
if (this.socket) {
this.socket.end();
this.socket = null;
}
reject(err);
});
})
.catch(() => {
return Promise.delay(metricConfig.CONN_RETRY)
.then(() => this._connectSocket());
});
};
// Returns a map from metric names (as entered in metricConfig.js) to their metricTools.
ServerMetrics.prototype.getMetrics = function() {
return this.serverMetrics;
};
// Pushes ready server and client metrics to the aggregator
ServerMetrics.prototype.pushMetrics = function(metrics) {
if (this.enabled) {
return this._request(metrics.join(""))
.finally(() => {
this._push = setTimeout(() => this.attemptPush(), metricConfig.SERVER_PUSH_INTERVAL);
});
}
};
ServerMetrics.prototype._request = function(text) {
return new Promise(resolve => {
if (!this.enabled) {
resolve();
return;
}
this.socket.write(text, 'utf8', () => {
log.info('Pushed metrics to Carbon');
resolve();
});
})
.catch(() => {
return this._connectSocket()
.then(() => this._request(text));
});
};
/**
* Function exposed to comm interface to provide server with client list of metrics.
* Used so that ServerMetrics can associate indices to client metric names.
* @param {Array} metricNames - A list of client metric names in the order in which values will be sent.
*/
ServerMetrics.prototype.registerClientMetrics = function(client, metricNames) {
this.clientNames = metricNames;
};
/**
* Function exposed to comm interface to allow client metrics to be pushed to this file,
* so that they may in turn be pushed to Carbon with the server metrics.
* @param {Array} data - A list of client buckets as defined in ClientMetrics.js's createBucket
*/
ServerMetrics.prototype.pushClientMetrics = function(client, data) {
// Merge ready client bucket metrics into ready server buckets.
if (!this.clientNames) {
throw new Error("Client metrics must be registered");
}
data.forEach(clientBucket => {
// Label the bucket with the client id so that clients' metrics do not replace one another
let clientData = clientBucket.values.map((val, i) => {
return this._stringifyMetric(this.clientNames[i], client.clientId, val, clientBucket.startTime);
}).join("");
this.queueBucket(clientData);
});
};
ServerMetrics.prototype.get = function(name) {
this.prepareCompletedBuckets(Date.now());
return this.serverMetrics[name];
};
/**
* Creates string bucket with metrics in carbon's text format.
* For details, see phriction documentation: https://phab.getgrist.com/w/metrics/
*/
ServerMetrics.prototype.createBucket = function(bucketStart) {
var data = [];
var bucketEnd = bucketStart + metricConfig.BUCKET_SIZE;
this.forEachBucketMetric(bucketEnd, tool => {
if (tool.getValue(bucketEnd) !== null) {
data.push(this._stringifyMetric(tool.getName(), this.serverId, tool.getValue(bucketEnd), bucketStart));
}
});
return data.join("");
};
// Helper to stringify individual metrics for carbon's text format.
ServerMetrics.prototype._stringifyMetric = function(name, id, val, startTime) {
// Server/client id is added to name for differentiating inputs to aggregator
return `${this._prefix}.${name}.${id} ${val} ${startTime/1000}\n`;
};
/**
* Static get method to retreive server metric recording tools.
* IMPORTANT: Usage involves the side effect of updating completed buckets and
* adding them to a ready object. get() results should not be assigned to variables and
* reused, rather get() should be called each time a metric is needed.
*/
ServerMetrics.get = function(name) {
if (!globalServerMetrics) {
throw new Error('Must create ServerMetrics instance to access server metrics.');
}
return globalServerMetrics.get(name);
};
module.exports = ServerMetrics;