Class: MonitorType

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

Overview

Base class for Monitors

Given that this is a DSL, it extracts named parameters from a hash in order to provide more precise reporting of errors, without spewing syntax errors at a user

Direct Known Subclasses

MonitorType_Threshold

Instance Method Summary collapse

Constructor Details

#initialize(params) ⇒ MonitorType

Check that all required parameters have been passed in Make sure that any errors encountered are reported in a way that fixing the error is made easier



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# File 'lib/MonitorType.rb', line 21

def initialize( params )
    if params[:name].nil? then
        puts "*** Monitor parameter missing, name"
        puts "*** :name => <name of monitor>"
        abort
    end
    @name = params[:name]
    @email = params[:email]
    if !@email.nil? then
        if params[:email_sender].nil? then
            if ENV["EMAIL_SENDER"].nil? then
                puts "*** Alert parameter missing, email_sender"
                puts "*** An email recipient has been specified for monitor, #{@name}, but no email sender has been specified"
                puts "*** :email_sender => <email of sender>"
                puts "*** or, a catch all environment variable"
                puts "*** EMAIL_SENDER=<email of sender>"
                abort
            else
                @admin_email = ENV["EMAIL_SENDER"]
            end
        else
            @admin_email = params[:admin_email]
        end
    end
    
    cron_string = params[:cron] || "0 1 * * *"
    @cron = CronParser.new(cron_string)
    @next = Time.now - 1
    
    log "Loaded Monitor, #{@name}."
end

Instance Method Details

#alert(string) ⇒ Object

Called when a monitor has been tripped

Parameters:

  • string (String) —

    A description of the trip that occurred



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# File 'lib/MonitorType.rb', line 82

def alert( string )
       body = "#{@name} tripped.\n#{string}"
       puts "*** "
  if !@email.nil? then
    Alert_Email.new( @email, body ).Send
           puts "Emailed, #{@email}"
           else
           puts body
  end
end

#process ⇒ Object

Check if the monitor has tripped



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# File 'lib/MonitorType.rb', line 58

def process
    raise "Method needs to be overridden"
end

#run ⇒ Object

An extention of the main run loop. Each monitor is responsible for knowing when it should run, so this function is called pretty much continuosuly.



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# File 'lib/MonitorType.rb', line 66

def run
    if Time.now > @next then
        begin
            @next = @cron.next( Time.now )
            log "Monitor, #{@name}, next run time, #{@next}"
            self.sanitise
            self.process
            rescue MonitorTypeExceptionHandled => e
            self.alert( e.message )
        end
    end
end

#sanitise ⇒ Object

Overload this method if any parameters should be checked in context



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# File 'lib/MonitorType.rb', line 54

def sanitise
end