Module: Perus::Server::DB

Defined in:
lib/perus/server/db.rb

Constant Summary collapse

MAX_VACUUM_ATTEMPTS = 
5

Class Method Summary collapse

Class Method Details

.cleanup ⇒ Object 



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# File 'lib/perus/server/db.rb', line 114

def self.cleanup
    puts 'Cleaning old values and metrics'
    keep_hours = Server.options.keep_hours

    # remove old values
    min_timestamp = Time.now.to_i - (keep_hours * 60 * 60)
    values = Value.where("timestamp < #{min_timestamp}")
    puts "Deleting #{values.count} values"
    values.each(&:destroy)

    # remove metrics from systems if they no longer have any values
    empty_deleted = 0
    file_deleted = 0

    Metric.each do |metric|
        if metric.file
            path = metric.path
            if !File.exists?(path) || File.mtime(path).to_i < min_timestamp
                metric.destroy
                file_deleted += 1
            end
        elsif metric.values_dataset.empty?
            metric.destroy
            empty_deleted += 1
        end
    end

    puts "#{empty_deleted} metrics were deleted as they had no values"
    puts "#{file_deleted} metrics were deleted as they had old files"
end

.db ⇒ Object 



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# File 'lib/perus/server/db.rb', line 9

def self.db
    @db
end

.start ⇒ Object 



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# File 'lib/perus/server/db.rb', line 13

def self.start
    puts 'Loading database'
    Sequel.extension :migration
    Sequel.extension :inflector

    # connect/create the database and run any new migrations
    @db = Sequel.sqlite(Server.options.db_path, integer_booleans: true)
    Sequel::Migrator.run(@db, File.join(__dir__, 'migrations'))

    # load models - these rely on an existing db connection
    Dir.chdir(File.join(__dir__, 'models')) do
        require './system'
        require './config'
        require './value'
        require './group'
        require './error'
        require './alert'
        require './action'
        require './metric'
        require './script'
        require './command_config'
        require './script_command'
        require './config_metric'
        require './active_alert'
    end
end

.start_timers ⇒ Object 



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# File 'lib/perus/server/db.rb', line 40

def self.start_timers
    # attempt to run vacuum twice a day. this is done to increase
    # performance rather than reclaim unused space. as old values and
    # metrics are deleted the data become very fragmented. vacuuming
    # restructures the db so system records in the values index should
    # be sequentially stored
    vacuum_task = Concurrent::TimerTask.new do
        attempts = 0
        complete = false

        while !complete && attempts < MAX_VACUUM_ATTEMPTS
            begin
                puts "Vacuuming, attempt #{attempts + 1}"
                start = Time.now
                @db.execute('vacuum')
                Stats.vacuumed!(Time.now - start)
                complete = true
                puts "Vacuuming complete"
                
            rescue
                attempts += 1
                if attempts < MAX_VACUUM_ATTEMPTS
                    puts "Vacuum failed, will reattempt after short sleep"
                    sleep(5)
                end
            end
        end

        if !complete
            puts "Vacuum failed more than MAX_VACUUM_ATTEMPTS"
            Stats.vacuumed!('failed')
        end
    end

    # fire every 12 hours
    vacuum_task.execution_interval = 60 * 60 * 12
    vacuum_task.execute

    # a fixed number of hours of data are kept in the database. once an
    # hour, old values and files are removed. if all values of a metric
    # are removed from a system, the accompanying metric record is also
    # removed.
    cleanup_task = Concurrent::TimerTask.new do
        begin
            start = Time.now
            Perus::Server::DB.cleanup
            Stats.cleaned!(Time.now - start)
        rescue
            Stats.cleaned!('failed')
        end
    end

    # fire every hour
    cleanup_task.execution_interval = 60 * 60
    cleanup_task.execute

    # alerts can be process intensive, so to keep page refreshes
    # responsive the 'active' state of an alert for each system is
    # cached so lookups can be done against the db, rather than running
    # each alert for each system on a page load.
    cache_alerts_task = Concurrent::TimerTask.new do
        begin
            start = Time.now
            Perus::Server::Alert.cache_active_alerts
            Stats.alerts_cached!(Time.now - start)
        rescue
            Stats.alerts_cached!('failed')
        end
    end

    cache_alerts_task.execution_interval = Server.options.cache_alerts_secs
    cache_alerts_task.execute
end