System Watcher

Setup

1. Add NPM package

npm init
npm install --save sys-watcher

2. Create watcher.js with following code as an example

const SysWatcher = require('sys-watcher');

let watcher = new SysWatcher();

watcher.start();

3. Create config.js with following code as an example

module.exports =
  { caching: {
      file3min: {
        type: 'FileCache'
      , settings: {
          lifespan: '3 min'
        }
      }
    , redis3min: {
        type: 'RedisCache'
      , settings: {
          lifespan: '3 min'
        }
      }
    }
  , loggers: {
      email: {
        type: 'MailLogger'
      , settings: {
          recipients: [ '<your e-mail address>' ]
        , sender: '<sender e-mail address>'
        }
      , composing: {
          format: 'text'
        , hostInfo: true
        , locationInSubject: true
        , subject: 'Error report'
        }
      }
    , slackChannel: {
        type: 'SlackLogger'
      , settings: {
          kind: 'webhook'
        , webHooks: [ '<url to channel webhook>' ]
        }
      , composing: {
          hostInfo: true
        }
      }
    , slackDirect: {
        type: 'SlackLogger'
      , settings: {
          kind: 'direct'
        , token: '<slack app token>'
        , recipients: [ '<slack recipient>' ]
        }
      , composing: {
          hostInfo: true
        }
      }
    , telegram: {
        type: 'TelegramLogger'
      , settings: {
          token: '<telegram bot token>'
        , recipients: [ <telegram user ID> ]
        }
      , composing: {
          hostInfo: true
        }
      }
    , AWSFreeSpaceCloudWatch: {
        type: 'AWSCloudWatchLogger'
      , settings: {
          metricName: 'FreeSpace'
        , nameSpace: 'TESTING'
        , units: 'Bytes'
        , AWS: {
            region: 'us-east-1'
          , accessKeyId: '<AWS Access Key>'
          , secretAccessKey: '<AWS Secret>'
          }
        }
      , composing: {
          hostInfo: true
        , locationInfo: true
        }
      }
    }
  , globals: {
      location: '<Name of your server>'
    , onStart: {
        composing: {
          hostInfo: true
        }
      , loggers: [ 'email', 'slackDirect' ]
      , cache: 'file3min'
      }
    , onError: {
        loggers: [ 'slackChannel', 'telegram' ]
      , composing: {
          hostInfo: true
        }
      , cache: 'redis3min'
      }
    }
  , watchers: {
      freeSpaceWatcher: {
        type: 'FreeSpaceWatcher'
      , settings: {
          path: '/'
        , threshold: '1 Gb'
        }
      , loggers: [ 'email', 'slackDirect' ]
      , scheduling: {
          interval: '5 min'
        }
      }
    , freeRAMWatcher: {
        type: 'FreeRAMWatcher'
      , settings: {
          threshold: '16 Gb'
        }
      , loggers: [ 'email', 'slackDirect' ]
      , scheduling: {
          interval: '1 min'
        }
      }
    , apacheErrorLog: {
        type: 'FileWatcher'
      , settings: {
          path: [ '/var/log/httpd/error_log' ]
        , rules: {
            all: {
              match: [ '([0-9]+[/][0-9]+[/][0-9]+ [0-9]+\:[0-9]+\:[0-9]+ \[error\] [0-9#]+\: [0-9*]+) (.+)' ]
            , cacheKey: '$2'
            }
          }
        }
      , loggers: [ 'email', 'slackDirect' ]
      , cache: 'redis3min'
      }
    , CMWatcher: {
        type: 'ConfigurationWatcher'
      , settings: {
          rules:[
            { cmd: 'node -v', check: '(8|10).16.(0|1|2)' }
          ]
        }
      , scheduling: {
          interval: '60 minutes'
        }
      , loggers: [ 'email', 'slackDirect' ]
      , cache: 'redis'
      }
    }
  };

4. Run the watcher

node watcher.js start

Run using pm2 http://pm2.keymetrics.io.

The best way to make sure watcher is always up and running is to use pm2.

1. Create ecosystem.config.yml using following code as an example:

apps:
  - script      : ./watcher.js
    name        : 'Watcher'
    cwd         : '/usr/local/node/sys-watcher/'
    args        : 'start --config config.js'
    treekill    : false
    watch       : true
    watch_delay : 1000
    ignore_watch:
      - .git
      - node_modules
    error_file  : '/var/log/node/sys-watcher.err'
    out_file    : '/var/log/node/sys-watcher.log'
    combine_logs: true
    max_memory_restart: '200M'

2. Run watcher through pm2

pm2 start

3. Check it's running using

pm2 ls

4. Check logs using

pm2 logs

Components

Watchers

• AWSSQSWatcher
• ConfigurationWatcher
• CronWatcher
• DirectoryWatcher
• FileWatcher
• FreeRAMWatcher
• FreeSpaceWatcher
• GitHubWebHookWatcher
• HTTPWatcher
• MailQueueWatcher
• MySQLWatcher
• ProcessWatcher
• RabbitMQWatcher
• SSLCertificateWatcher
• WebWatcher

Caching engines

• FileCache
• RedisCache

Loggers

• AWSCloudWatchLogger
• ConsoleLogger
• MailLogger
• RabbitMQLogger
• SlackLogger
• TelegramLogger