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 30

def initialize( params )
    if params[:name].nil? then
        string = "*** Monitor parameter missing, name"
        string = "#{string}*** :name => <name of monitor>"
        raise MonitorTypeMustHaveNameError.new(string)
    end
    @params = params
    @block = params[:block] unless params[:block].nil?
    @name = params[:name]
    @email = params[:email]
    @url = params[:url] unless params[:url].nil?

    if !@email.nil? then
        #Sender email address from ENV allows for a single sender across all alerts
        #Checking params before ENV allows a particular entry to be different
        if params[:email_sender].nil? then
            if ENV["EMAIL_SENDER"].nil? then
                string = "*** Alert parameter missing, email_sender"
                string = "#[string}*** An email recipient has been specified for monitor, #{@name}, but no email sender has been specified"
                string = "#[string}*** :email_sender => <email of sender>"
                string = "#[string}*** or, a catch all environment variable"
                string = "#[string}*** EMAIL_SENDER=<email of sender>"

                raise MonitorTypeMustHaveSenderEmailAddressForEmailAlertError.new(string)
                else
                @sender_email = ENV["EMAIL_SENDER"]
            end
            else
            @sender_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 108

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

#extractParams ⇒ Object

Overload this method if any parameters should be checked in context



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# File 'lib/MonitorType.rb', line 70

def extractParams
end

#process ⇒ Object

Check if the monitor has tripped



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

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 90

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

#setup ⇒ Object

Overload this method if any parameters should be checked in context



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# File 'lib/MonitorType.rb', line 74

def setup
end

#teardown ⇒ Object

Overload this method if any parameters should be checked in context



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# File 'lib/MonitorType.rb', line 78

def teardown
end