Class: Recmon::Monitor

Inherits:
Object
  • Object
show all
Defined in:
lib/recmon/monitor.rb

Overview

The Monitor manages the list of sensors, and calls on them periodically to report their results.

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(log = "/var/log/recmon.log", name = "recmond", freq = 10) ⇒ Monitor

Creates a new monitor, writing to the given log file. The default frequency of 10 seconds is frequent enough to be near-real-time without any burden on the processor. This is the frequency on which the monitor checks if any sensors are due - not the frequency for each sensor. The name is used in the process list (ps, top).



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# File 'lib/recmon/monitor.rb', line 18

def initialize(log="/var/log/recmon.log", name="recmond", freq=10)
  @logfile = log
  @name = name
  @freq = freq  # seconds
  @log = ""
  @sensors = []
end

Instance Attribute Details

#sensors ⇒ Object (readonly)

Returns an array of sensors



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# File 'lib/recmon/monitor.rb', line 11

def sensors
  @sensors
end

Instance Method Details

#command(name, command, freq = 120) ⇒ Object

Adds a CommandSensor



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# File 'lib/recmon/monitor.rb', line 82

def command(name, command, freq=120)
  @sensors << Recmon::CommandSensor.new(name, command, freq)
end

#diskfree(name, freq = 1200) ⇒ Object

Adds a DiskfreeSensor



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# File 'lib/recmon/monitor.rb', line 87

def diskfree(name, freq=1200)
  @sensors << Recmon::DiskfreeSensor.new(name, freq)
end

#diskspace(name, path, freq = 1200) ⇒ Object

Adds a DiskspaceSensor



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# File 'lib/recmon/monitor.rb', line 92

def diskspace(name, path, freq=1200)
  @sensors << Recmon::DiskspaceSensor.new(name, path, freq)
end

#filesize(name, path, freq = 1200) ⇒ Object

Adds a FilesizeSensor



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# File 'lib/recmon/monitor.rb', line 97

def filesize(name, path, freq=1200)
  @sensors << Recmon::FilesizeSensor.new(name, path, freq)
end

#log(message) ⇒ Object

Logs a message to the log file



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# File 'lib/recmon/monitor.rb', line 77

def log(message)
  @log.puts("#{Time.now.iso8601} #{message}")
end

#monitor ⇒ Object

Checks the list of sensors to see if any are due to report



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# File 'lib/recmon/monitor.rb', line 71

def monitor()
  @sensors.each { |s| log(s.sense()) if s.check()  }
  @log.flush()
end

#open_log ⇒ Object

opens the log file - occurs on starting, and if HUP signal is received



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# File 'lib/recmon/monitor.rb', line 55

def open_log()
  begin
    @log = File.new(@logfile, 'a')
  rescue
    exit 1
  end
end

#ping(name, ip, freq = 120) ⇒ Object

Adds a PingSensor



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# File 'lib/recmon/monitor.rb', line 102

def ping(name, ip, freq=120)
  @sensors << Recmon::PingSensor.new(name, ip, freq)
end

#proc(name, pattern, freq = 60) ⇒ Object

Adds a ProcSensor



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# File 'lib/recmon/monitor.rb', line 107

def proc(name, pattern, freq=60)
  @sensors << Recmon::ProcSensor.new(name, pattern, freq)
end

#ssh(name, user, port = 22, freq = 120) ⇒ Object

Add an SSHSensor



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# File 'lib/recmon/monitor.rb', line 112

def ssh(name, user, port=22, freq=120)
  @sensors << Recmon::SSHSensor.new(name, user, port, freq)
end

#start ⇒ Object

Starts the monitor running until an INT signal is received.



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# File 'lib/recmon/monitor.rb', line 27

def start()
  trap("HUP") {  # defer monitoring for a minute and reopen log files
    @log.close() unless @log.nil? or @log.closed?
    sleep(60)
    open_log()
  }
  trap("INT") {
    stop()
  }
  open_log()
  # daemonise the process
  $0 = @name
  fork do
    Process.setsid
    exit if fork
    File.umask 0027 # default mode => 0750
    STDIN.reopen "/dev/null"
    STDOUT.reopen @log
    STDERR.reopen @log
    log("Recmon is monitoring.")
    monitor()
    while sleep(@freq)
      monitor()
    end
  end
end

#stop ⇒ Object

Stops the monitor



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# File 'lib/recmon/monitor.rb', line 64

def stop()
  log("Recmon is exiting.")
  @log.close() unless @log.nil? or @log.closed?
  exit 0
end

#web(name, url, freq = 120) ⇒ Object

Adds a WebSensor



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# File 'lib/recmon/monitor.rb', line 117

def web(name, url, freq=120)
  @sensors << Recmon::WebSensor.new(name, url, freq)
end