Class: ScoutApm::Capacity

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

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize ⇒ Capacity

Returns a new instance of Capacity.



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# File 'lib/scout_apm/capacity.rb', line 6

def initialize
  @processing_start_time = Time.now
  @lock ||= Mutex.new # the transaction_entry_time could be modified while processing a request or when #process is called.
  @accumulated_time = 0.0
end

Instance Attribute Details

#accumulated_time ⇒ Object (readonly)

Returns the value of attribute accumulated_time.



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# File 'lib/scout_apm/capacity.rb', line 4

def accumulated_time
  @accumulated_time
end

#processing_start_time ⇒ Object (readonly)

Returns the value of attribute processing_start_time.



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# File 'lib/scout_apm/capacity.rb', line 4

def processing_start_time
  @processing_start_time
end

#transaction_entry_time ⇒ Object (readonly)

Returns the value of attribute transaction_entry_time.



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# File 'lib/scout_apm/capacity.rb', line 4

def transaction_entry_time
  @transaction_entry_time
end

Instance Method Details

#finish_transaction! ⇒ Object

Called when a transaction completes to record its time used.



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# File 'lib/scout_apm/capacity.rb', line 20

def finish_transaction!
  @lock.synchronize do
    if transaction_entry_time
      @accumulated_time += (Time.now - transaction_entry_time).to_f
    else
      ScoutApm::Agent.instance.logger.warn "No transaction entry time. Not recording capacity metrics for transaction."
    end
    @transaction_entry_time = nil
  end
end

#process ⇒ Object

Ran when sending metrics to server. Reports capacity usage metrics.



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# File 'lib/scout_apm/capacity.rb', line 32

def process
  process_time = Time.now
  ScoutApm::Agent.instance.logger.debug "Processing capacity usage for [#{@processing_start_time}] to [#{process_time}]. Time Spent: #{@accumulated_time}."
  @lock.synchronize do
    time_spent = @accumulated_time
    @accumulated_time = 0.0
    # If a transaction is still running, capture its running time up to now and
    # reset the +transaction_entry_time+ to now.
    if @transaction_entry_time
      time_spent += (process_time - @transaction_entry_time).to_f
      ScoutApm::Agent.instance.logger.debug "A transaction is running while calculating capacity. Start time: [#{transaction_entry_time}]. Will update the entry time to [#{process_time}]."
      @transaction_entry_time = process_time # prevent from over-counting capacity usage. update the transaction start time to now.
    end
    time_spent = 0.0 if time_spent < 0.0

    window = (process_time - processing_start_time).to_f # time period we are evaulating capacity usage.
    window = 1.0 if window <= 0.0 # prevent divide-by-zero if clock adjusted.
    capacity = time_spent / window
    ScoutApm::Agent.instance.logger.debug "Instance/Capacity: #{capacity}"
    ScoutApm::Agent.instance.store.track_one!("Instance", "Capacity", capacity)

    @processing_start_time = process_time
  end
end

#start_transaction! ⇒ Object

Called when a transaction is traced.



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# File 'lib/scout_apm/capacity.rb', line 13

def start_transaction!
  @lock.synchronize do
    @transaction_entry_time = Time.now
  end
end