Meteor server info

• A NPM version (derivative work) of percolate:server-info
• Rewritten in TypeScript 3 for Meteor 1.6-1.8.1
• Without the AWS-specific and extra sections, not relevant for most usages.
• With 3 original Node.JS EventLoop metrics collectors (see "Configuration")

Usage

Once installed and configured, the package provides

• a public metrics documentation route, available by default on /serverInfo/doc where all exposed metrics are documented
• a metrics values route available with HTTP Basic authentication, by default on /serverInfo, like the following one:

Installation

• Like the original version, this project needs the MDG Facts package, but not the facts-uipackage. So from the project directory, add both dependencies:

meteor add facts
meteor yarn add meteor_server_info

• Then, in the main JS file of the server part of the application, add code to initialize the package:

import { ServerInfo } from "meteor_server_info";

Meteor.startup(function () {
  const serverInfo = new ServerInfo(Meteor, WebApp, MongoInternals, Facts);
  serverInfo.register();
});

• Edit the Meteor settings, at least to change the user and password.
• Run your application normally.

Development installation

To work on the package, you will probably not want to use it via NPM/Yarn. In that case:

• do NOT add it to your package.json
• clone it in the import/server/ directory of your project,
• import its dependencies with meteor yarn
• build documentation with yarn && yarn doc. The documentation will be built in the out/ directory.
• compile with meteor yarn ts-compile, lint with meteor yarn ts-lint and run tests with meteor yarn test-ci

To use your development version of the module, import it locally in your application code. You will have access to serverInfo from meteor shell.

// Heed the "./" import.
import { ServerInfo } from "./meteor_server_info";

Meteor.startup(function () {
  const serverInfo = new ServerInfo(Meteor, WebApp, MongoInternals, Facts);
  serverInfo.register();
  global.serverInfo = serverInfo;
});

That way, any time you recompile the module, you application will notice the JS changes and rebuild/restart itself.

Configuration

The packages takes configuration from Meteor.settings, in which it uses the following server keys:

• path: the path on which the information is made available. Defaults to /serverInfo, unlike the original version which defaulted to /info.
• user: the user account for the HTTP Basic authentication securing access. Defaults to insecure.
• pass: the password for the user account. Defaults to secureme.
• verbose: enable console logging. Defaults to false.
• eventLoopStrategy: the strategy to use to instrument the event loop and/or statistical CPU usage
  • "els": a set of event-loop metrics provided by the event-loop-stats package. Cheap and accurate, this is the recommended collector.
  • "nr": inspired by NewRelic "CPU time per tick", an intuitive metric collecting instantaneous CPU usage across ticks, based on a Dynatrace article, tracing each tick of the event loop in JavaScript code, which makes it rather costly since it disables the event loop "poll phase wait" optimization to achieve accuracy: expect 8% CPU load.
  • false, the event loop metrics collection is disabled, to keep costs at an absolute minimum like the legacy MeteorServerInfo.

The package previously included a "cheap" collector based on the PM2 / pebble/event-loop-lag logic, but this has been superseded by the ELS collector.

Usage note

Metrics exposed by the module can easily be imported to Grafana using the http plugin and a Telegraf import. Be sure to import data from all your Meteor server instances, since metrics are reported per-server, not per-database.

Note that since the nr collector disables the event loop poll phase wait optimization, the idle ticks/second rate will be around 900 and go lower with increased load. There is a tradeoff to be done: CPU cost vs accuracy.

The high cost of this strategy is a consequence of the limitations of the Node.JS event loop JavaScript API, requiring workarounds. For accurate metrics with lower metric acquisition cost, a binary agent is required, like the ELS collector, or commercial offerings: AppDynamics, Dynatrace, NewRelic and others offer this type of solution, the tradeoff in that case being CPU cost vs monthly SaaS cost.

License

As the original percolate:server-info package was licensed under the permissive MIT license, this derivative work has been relicensed under the General Public License version 3 or later (SPDX: GPL-3.0+).

Changelog

• 1.2.7
  • Use base version of event-loop-stats now that fork has been merged.
• 1.2.6
  • ElsCounter now includes a LoopCountPerSecondSinceLastFetch building an average between fetches, and reset on each fetch.
  • BC break: Removed CheapCounter and CostlyCounter, entirely superseded by ElsCounter
  • Garbage collection now uses gc-stats 1.4.0 stable version.
  • tickLagMax renamed to loopLagMaxMsecSinceLastFetch
  • New doc/NodeCounters.md detailing the rationale for the changes since 1.2.5.
  • TypeScript 3.5, Node 12 types, other minor dependency updates.
• 1.2.5
  • Native event loop metrics from package event-loop-stats as a more efficient alternative to CostlyCounter and NrCounter.
  • As a consequence, those are now deprecated and will be removed no later than version 1.3.
  • CheapCounter metrics now return a high-resolution duration instead of a struct.
  • Dev API: interface ICounter removed,
• 1.2.4
  • Same as 1.2.3, but also working on Meteor 1.8.1
  • Session info are no longer null on Meteor 1.8.1
  • Socket metrics also work in meteor run mode on Meteor 1.8.1
• 1.2.3
  • New garbage collector metrics from package gc-stats.
  • TypeScript 3.4.
• 1.2.2
  • New tickLagMax in NrCounter. Other metrics renamed and reworded for intelligibility.
  • TypeScript 3.3.
  • Over 70% new test coverage for NrCounter and CounterBase.
• 1.2.1
  • Node.JS EventLoop and CPU metrics, 3 strategies at different accuracy and cost levels
  • TypeScript 3.2.
  • Documentation converted from Jsdoc to Typedoc.
  • 100% test coverage of NodeInfo and SessionInfo.
• 1.2.0
  • Converted to TypeScript 3, with increased coverage
  • Compatibility with Meteor 1.7 and 1.8.
• 1.1.2
  • updated documentation.
  • Travis CI tests.
  • CodeCov coverage analysis.
• 1.1.1
  • include RAM / CPU metrics.
• 1.0.1
  • added an explicit dev dependency on marked 0.3.9 to work around https://github.com/jsdoc3/jsdoc/issues/1489 - can be removed once jsdoc updates its dependency to that level.
  • updated JsDoc to 3.5.5.
  • fixed JsDoc configuration so that npm run doc actually works
• 1.0.0: initial version
  • For Meteor 1.6.x