❯ Why

You want to log service metrics from your application on Cloud Foundry? - Yes? - Here you are 🙌 !!

❯ Table of Contents

• Supported Services
• Quick Start
• API
• Development
• Project Structure

❯ Supported Services

| Service | Version | | ----------- | ------- | | MongoDB | >=3.6.6 | | Redis | >=2.3.9 |

❯ Quick Start

Installation

Install library by using npm

npm install cf-service-metrics-logger

or by using yarn

yarn add cf-service-metrics-logger

How to use

Step 1: Import CfServiceMetricsLogger

Using CommonJS module loader:

const CfServiceMetricsLogger = require('cf-service-metrics-logger');

Using ES6 module loader:

import { CfServiceMetricsLogger } from 'cf-service-metrics-logger';

Step 2: Create new instance of CfServiceMetricsLogger

Create new instance of CfServiceMetricsLogger and provide options:

const options = {
  mongoDB: {
    serverStatusInterval: 10000,
    dbStatsInterval: 20000,
  },
  redis: {
    infoInterval: 100000
  }
};

const cfServiceMetricsLogger = new CfServiceMetricsLogger(options);

Step 3: Subscribe to receive service metrics and general logs

Subscribe metrics to receive service metrics data:

cfServiceMetricsLogger.subscribe('metrics', data => {
  // do some fancy stuff with your metrics
});

Subscribe logs to receive general application logs:

cfServiceMetricsLogger.subscribe('logs', {message, level} => {
  console[level](message));
});

Step 3: Start and stop service metrics logging

Start service metrics logging:

cfServiceMetricsLogger.start();

Stop service metrics logging:

cfServiceMetricsLogger.stop();

❯ API

Options

| Option | Description | Default Value | | ----------------------------------------- | -------------------------------------------------------------- | ------------: | | mongoDb.serverStatusInterval (optional) | MongoDb database status polling interval in ms | 10000 | | mongoDb.dbStatsInterval (optional) | MongoDB storage statistics polling interval in ms | 10000 | | redis.infoInterval (optional) | Redis statistics polling interval | 10000 | | vcap (optional) | Provide local VCAP_SERVICES and/or VCAP_APPLICATION values | {} | | vcapFile (optional) | Provide local VCAP_SERVICES and/or VCAP_APPLICATION file | '' |

Methods

| Method | Description | | -------------------------------- | ---------------------- | | start() | Start service metrics | | stop() | Stop service metrics | | subscribe(eventId, callback) | Subscribe an event | | unsubscribe(eventId, callback) | Unsubscribe an event | | unsubscribeAll() | Unsubscribe all events |

Subscription event id's

| Id | Description | | --------- | ---------------------------------------------------------------------- | | metrics | Service metrics | | logs | General application logs for levels debug, info, warn and error |

❯ Development

Getting Started

Step 1: Set up the Development Environment

You need to set up your development environment before you can do anything.

Install Node.js and NPM

• on OSX use homebrew brew install node
• on Windows use chocolatey choco install nodejs

Install yarn globally

yarn install yarn -g

Step 2: Set up Environment Variables

Copy the vcap.example.json file and rename it to vcap.json. This file provides VCAP_SERVICES and/or VCAP_APPLICATION for local development. More information is provided here.

Step 3: Install dependencies

Install all dependencies with yarn.

yarn install

Scripts and Tasks

Install

• Install all dependencies with yarn install

Linting

• Run code quality analysis using yarn run lint. This runs tslint.

Tests

• Run unit test using yarn run test.

Building the project

• Run yarn run build to generate commonJS and ES6 modules as well as declaration from the TypeScript source.
• Builded sources are located in dist folder.

Debugger

VS Code

Just set a breakpoint in source or unit test and hit F5 in your Visual Studio Code to execute and debug all unit tests.

❯ Project Structure

| Name | Description | | --------------------------------- | ----------- | | .vscode/ | VSCode tasks, launch configuration and some other settings | | dist/ | Compiled and bundled source files will be placed here | | src/ | Source files | | src/types/ *.d.ts | Custom type definitions and files that aren't on DefinitelyTyped | | test/ | Tests | | test/unit/ *.test.ts | Unit tests | | vcap.example.json | Provides VCAP_SERVICES and/or VCAP_APPLICATION for local development | | vcap.test.json | Provides VCAP_SERVICES and/or VCAP_APPLICATION for unit tests | | rollup.config.js | Config for Rollup module bundler |