Class: RailsErrorDashboard::Services::CascadeDetector

Inherits:
Object
  • Object
show all
Defined in:
lib/rails_error_dashboard/services/cascade_detector.rb

Overview

Detects cascade patterns by analyzing error occurrences

Runs periodically to find errors that consistently follow other errors, indicating a causal relationship.

Constant Summary collapse

DETECTION_WINDOW =

Time window to look for cascades (errors within this window may be related)

60.seconds
MIN_CASCADE_FREQUENCY =

Minimum times a pattern must occur to be considered a cascade

3
MIN_CASCADE_PROBABILITY =

Minimum probability threshold (% of time parent leads to child)

0.7

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(lookback_hours: 24) ⇒ CascadeDetector

Returns a new instance of CascadeDetector.



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# File 'lib/rails_error_dashboard/services/cascade_detector.rb', line 23

def initialize(lookback_hours: 24)
  @lookback_hours = lookback_hours
  @detected_count = 0
end

Class Method Details

.call(lookback_hours: 24) ⇒ Object 



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# File 'lib/rails_error_dashboard/services/cascade_detector.rb', line 19

def self.call(lookback_hours: 24)
  new(lookback_hours: lookback_hours).detect_cascades
end

Instance Method Details

#detect_cascades ⇒ Object 



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# File 'lib/rails_error_dashboard/services/cascade_detector.rb', line 28

def detect_cascades
  return { detected: 0, updated: 0 } unless can_detect?

  # Get recent error occurrences
  start_time = @lookback_hours.hours.ago
  occurrences = ErrorOccurrence.where("occurred_at >= ?", start_time).order(:occurred_at)

  # For each error occurrence, find potential children
  patterns_found = Hash.new { |h, k| h[k] = { delays: [], count: 0 } }

  occurrences.each do |parent_occ|
    # Find occurrences within detection window
    potential_children = ErrorOccurrence
      .where("occurred_at > ? AND occurred_at <= ?",
             parent_occ.occurred_at,
             parent_occ.occurred_at + DETECTION_WINDOW)
      .where.not(error_log_id: parent_occ.error_log_id)

    potential_children.each do |child_occ|
      key = [ parent_occ.error_log_id, child_occ.error_log_id ]
      delay = (child_occ.occurred_at - parent_occ.occurred_at).to_f

      patterns_found[key][:delays] << delay
      patterns_found[key][:count] += 1
    end
  end

  # Filter and save cascade patterns
  updated_count = 0
  patterns_found.each do |(parent_id, child_id), data|
    next if data[:count] < MIN_CASCADE_FREQUENCY

    # Find or create cascade pattern
    pattern = CascadePattern.find_or_initialize_by(
      parent_error_id: parent_id,
      child_error_id: child_id
    )

    avg_delay = data[:delays].sum / data[:delays].size

    if pattern.new_record?
      pattern.frequency = data[:count]
      pattern.avg_delay_seconds = avg_delay
      pattern.last_detected_at = Time.current
      pattern.save
      @detected_count += 1
    else
      # Update existing pattern
      pattern.increment_detection!(avg_delay)
      updated_count += 1
    end

    # Calculate probability
    pattern.calculate_probability!
  end

  { detected: @detected_count, updated: updated_count }
end