fastify-health-info

Health check and info endpoints for fastify, with support for build and git details.

Install

npm install fastify-health-info

Usage

Register the plugin and your application will server /info, /health, and /metrics endpoints.

const fastify = require('fastify')()

fastify.register(require('fastify-health-info'))

They will give the following responses:

GET /health

{
  "status": "UP"
}

GET /info

{
  "node": {
    // the version of node your application is running
    "version": "20.0.0"
  },
  "application": {
    // the name of your app from package.json
    "name": "movies",
    // the description of your app from package.json
    "description": "movies database API",
    // the version of your app from package.json
    "version": "1.5.0"
  }
}

GET /metrics

{
  "uptime": 200,
  "cpu": {
    "user": 45,
    "system": 55
  },
  "memory": {
    "rss": 1000,
    "heapTotal": 3000,
    "heapUsed": 2000,
    "external": 4000,
    "arrayBuffers": 5000
  }
}

Disabling endpoints

You can turn off any of the endpoints you don't want with the following options:

fastify.register(require('fastify-health-info'), {
  // Disable /health endpoint
  disableHealth: true,
  // Disable /info endpoint
  disableInfo: true,
  // Disable /metrics endpoint
  disableMetrics: true
})

Context path

You can add a context path to the fastify-health-info endpoints by using the prefix option:

// Will now serve on /checks/health, for example
fastify.register(require('fastify-health-info'), {
  prefix: '/checks'
})

Git details

Commit details included in /info

You can able to reporting of some git commit information in the /info endpoint by setting the commitDetailsFrom option:

fastify.register(require('fastify-health-info'), {
  commitDetailsFrom: 'git'
})

A value of git will load commit information live from git on application startup. Alternatively you can load pre-built commit details from a file path, after first generating them using the gitdetails command line tool that comes with this pacakge. This is more useful where git will not be available and want details from build time.

npx gitdetails .git-details.json

fastify.register(require('fastify-health-info'), {
  commitDetailsFrom: './.git-details.json'
})

The JSON response from /info will now contain some commit information:

{
  "node": {
    "version": "20.0.0"
  },
  "application": {
    "name": "movies",
    "description": "movies database API",
    "version": "1.5.0"
  },
  "git": {
    "branch": "main",
    "commit": {
      "id":"12969afe5ff6b56ee47a4dd823a0c275dbe5fe66",
      "time":"2024-05-01T12:13:22.000Z"
    }
  },
  "build":{
    // Build time is only included when loading commit details from a built
    // git-details JSON file.
    "time":"2024-05-02T22:08:49.586Z"
  }
}

If HEAD is a tag commit, the application version will be the tagged version, otherwise it will be the last tag with a commit shorthash:

{
  ...
  "application": {
    // Tag commit at head
    "version": "1.5.0"
    // Commit not tagged
    "version": "1.5.0-g12969af"
  },
  ...
}

The git details are made available via the decorator app.commitDetails for use in your application:

Accessing git details from decorated app

const fastify = require('fastify')()

fastify.register(require('fastify-health-info'), {
  commitDetailsFrom: './.git-details.json'
})

fastify.get('/', function (request, reply) {
  reply.send(`We're on branch ${fastify.commitDetails.branch}!`)
})

Health check

This package comes with a health check script which you can use in docker images to call /health, which could be useful if curl or wget is not available inside your container.

The script will log healthy and exit on code 0 on receipt of a 200 sucess response, otherwise will log an error and exit with code 1.

By default the script will call http://localhost/health on port 8080 or the value of the PORT environment variable:

ENV PORT=3000

# GET http://localhost:3000/health
HEALTHCHECK CMD ./node_modules/.bin/healthcheck

If you have set a custom prefix you can set it using the path argument or the HEALTH_PATH environment variable:

ENV HEALTH_PATH=/checks/health

# GET http://localhost:8080/checks/health
HEALTHCHECK CMD ./node_modules/.bin/healthcheck

You can also set a separate HEALTH_BASE_PATH var:

ENV HEALTH_PATH=/checks/health
ENV HEALTH_BASE_PATH=/context-path

# GET http://localhost:8080/context-path/checks/health
HEALTHCHECK CMD ./node_modules/.bin/healthcheck

You can change the names of the variables the script will look for with the --port-var, --path-var and --base-var arguments - if you want to load a value from a pre-existing env var:

# GET http://localhost:${APP_PORT}/health
HEALTHCHECK CMD ./node_modules/.bin/healthcheck --port-var=APP_PORT