Class: DeadBro::ViewRenderingSubscriber

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

Constant Summary collapse

RENDER_TEMPLATE_EVENT =

Rails view rendering events

"render_template.action_view"
RENDER_PARTIAL_EVENT = 
"render_partial.action_view"
RENDER_COLLECTION_EVENT = 
"render_collection.action_view"
THREAD_LOCAL_KEY = 
:dead_bro_view_events
MAX_TRACKED_EVENTS = 
1000

Class Method Summary collapse

Class Method Details

.add_view_event(view_info) ⇒ Object 



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# File 'lib/dead_bro/view_rendering_subscriber.rb', line 81

def self.add_view_event(view_info)
  if Thread.current[THREAD_LOCAL_KEY] && should_continue_tracking?
    Thread.current[THREAD_LOCAL_KEY] << view_info
  end
end

.analyze_view_performance(view_events) ⇒ Object

Analyze view rendering performance



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# File 'lib/dead_bro/view_rendering_subscriber.rb', line 116

def self.analyze_view_performance(view_events)
  return {} if view_events.empty?

  total_duration = view_events.sum { |event| event[:duration_ms] }

  # Group by view type
  by_type = view_events.group_by { |event| event[:type] }

  # Find slowest views
  slowest_views = view_events.sort_by { |event| -event[:duration_ms] }.first(5)

  # Find most frequently rendered views
  view_frequency = view_events.group_by { |event| event[:identifier] }
    .transform_values(&:count)
    .sort_by { |_, count| -count }
    .first(5)

  # Calculate cache hit rates for partials
  partials = view_events.select { |event| event[:type] == "partial" }
  cache_hits = partials.count { |event| event[:cache_key] }
  cache_hit_rate = partials.any? ? (cache_hits.to_f / partials.count * 100).round(2) : 0

  # Collection rendering analysis
  collections = view_events.select { |event| event[:type] == "collection" }
  total_collection_items = collections.sum { |event| event[:count] || 0 }
  total_cached_items = collections.sum { |event| event[:cached_count] || 0 }
  collection_cache_hit_rate = (total_collection_items > 0) ?
    (total_cached_items.to_f / total_collection_items * 100).round(2) : 0

  {
    total_views_rendered: view_events.count,
    total_view_duration_ms: total_duration.round(2),
    average_view_duration_ms: (total_duration / view_events.count).round(2),
    by_type: by_type.transform_values(&:count),
    slowest_views: slowest_views.map { |view|
      {
        identifier: view[:identifier],
        duration_ms: view[:duration_ms],
        type: view[:type]
      }
    },
    most_frequent_views: view_frequency.map { |identifier, count|
      {
        identifier: identifier,
        count: count
      }
    },
    partial_cache_hit_rate: cache_hit_rate,
    collection_cache_hit_rate: collection_cache_hit_rate,
    total_collection_items: total_collection_items,
    total_cached_collection_items: total_cached_items
  }
end

.safe_identifier(identifier) ⇒ Object 



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# File 'lib/dead_bro/view_rendering_subscriber.rb', line 105

def self.safe_identifier(identifier)
  return "" unless identifier.is_a?(String)

  # Extract meaningful parts of the file path
  # e.g., "/app/views/users/show.html.erb" -> "users/show.html.erb"
  identifier.split("/").last(3).join("/")
rescue
  identifier.to_s
end

.should_continue_tracking? ⇒ Boolean

Check if we should continue tracking based on count and time limits

Returns:

  • (Boolean) 


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# File 'lib/dead_bro/view_rendering_subscriber.rb', line 88

def self.should_continue_tracking?
  events = Thread.current[THREAD_LOCAL_KEY]
  return false unless events

  # Check count limit
  return false if events.length >= MAX_TRACKED_EVENTS

  # Check time limit
  start_time = Thread.current[DeadBro::TRACKING_START_TIME_KEY]
  if start_time
    elapsed_seconds = Time.now - start_time
    return false if elapsed_seconds >= DeadBro::MAX_TRACKING_DURATION_SECONDS
  end

  true
end

.start_request_tracking ⇒ Object 



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# File 'lib/dead_bro/view_rendering_subscriber.rb', line 71

def self.start_request_tracking
  Thread.current[THREAD_LOCAL_KEY] = []
end

.stop_request_tracking ⇒ Object 



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# File 'lib/dead_bro/view_rendering_subscriber.rb', line 75

def self.stop_request_tracking
  events = Thread.current[THREAD_LOCAL_KEY]
  Thread.current[THREAD_LOCAL_KEY] = nil
  events || []
end

.subscribe!(client: Client.new) ⇒ Object 



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# File 'lib/dead_bro/view_rendering_subscriber.rb', line 15

def self.subscribe!(client: Client.new)
  # Track template rendering
  ActiveSupport::Notifications.subscribe(RENDER_TEMPLATE_EVENT) do |name, started, finished, _unique_id, data|
    duration_ms = ((finished - started) * 1000.0).round(2)

    view_info = {
      type: "template",
      identifier: safe_identifier(data[:identifier]),
      layout: data[:layout],
      duration_ms: duration_ms,
      virtual_path: data[:virtual_path],
      rendered_at: Time.now.utc.to_i
    }

    add_view_event(view_info)
  end

  # Track partial rendering
  ActiveSupport::Notifications.subscribe(RENDER_PARTIAL_EVENT) do |name, started, finished, _unique_id, data|
    duration_ms = ((finished - started) * 1000.0).round(2)

    view_info = {
      type: "partial",
      identifier: safe_identifier(data[:identifier]),
      layout: data[:layout],
      duration_ms: duration_ms,
      virtual_path: data[:virtual_path],
      cache_key: data[:cache_key],
      rendered_at: Time.now.utc.to_i
    }

    add_view_event(view_info)
  end

  # Track collection rendering (for partials rendered in loops)
  ActiveSupport::Notifications.subscribe(RENDER_COLLECTION_EVENT) do |name, started, finished, _unique_id, data|
    duration_ms = ((finished - started) * 1000.0).round(2)

    view_info = {
      type: "collection",
      identifier: safe_identifier(data[:identifier]),
      layout: data[:layout],
      duration_ms: duration_ms,
      virtual_path: data[:virtual_path],
      cache_key: data[:cache_key],
      count: data[:count],
      cached_count: data[:cached_count],
      rendered_at: Time.now.utc.to_i
    }

    add_view_event(view_info)
  end
rescue
  # Never raise from instrumentation install
end