Module: RailsNexus::Breadcrumbs

Defined in:
lib/rails_nexus/breadcrumbs.rb

Overview

Breadcrumbs capture activity trail before a crash. Uses ActiveSupport::Notifications to subscribe to SQL, controller, cache, and other instrumentation events.

Constant Summary collapse

RING_BUFFER_SIZE = 
50

Class Method Summary collapse

Class Method Details

.add(type:, name:, payload: nil, duration: nil) ⇒ Object

Capture a breadcrumb manually



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# File 'lib/rails_nexus/breadcrumbs.rb', line 23

def add(type:, name:, payload: nil, duration: nil)
  buffer << {
    type: type,
    name: name,
    payload: payload,
    duration: duration,
    timestamp: Time.current.iso8601(3)
  }
  # Keep only last N entries
  buffer.shift if buffer.size > RING_BUFFER_SIZE
end

.buffer ⇒ Object

Thread-local ring buffer of breadcrumbs



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# File 'lib/rails_nexus/breadcrumbs.rb', line 14

def buffer
  Thread.current[:rails_nexus_breadcrumbs] ||= []
end

.buffer=(val) ⇒ Object 



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# File 'lib/rails_nexus/breadcrumbs.rb', line 18

def buffer=(val)
  Thread.current[:rails_nexus_breadcrumbs] = val
end

.flush ⇒ Object

Flush buffer and return captured breadcrumbs



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# File 'lib/rails_nexus/breadcrumbs.rb', line 36

def flush
  crumbs = buffer.dup
  self.buffer = []
  crumbs
end

.reset! ⇒ Object

Reset state (for testing)



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# File 'lib/rails_nexus/breadcrumbs.rb', line 155

def reset!
  self.buffer = []
  @subscribed = false
end

.subscribe! ⇒ Object

Start subscribing to instrumentation events



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# File 'lib/rails_nexus/breadcrumbs.rb', line 43

def subscribe!
  return if @subscribed

  # SQL queries
  ActiveSupport::Notifications.subscribe("sql.active_record") do |_name, _start, _finish, _id, payload|
    next if payload[:name] == "SCHEMA"
    next if payload[:sql]&.start_with?("SET")
    next if payload[:sql]&.start_with?("SELECT 1")

    add(
      type: "sql",
      name: payload[:sql]&.truncate(200),
      payload: {
        connection_id: payload[:connection_id],
        cached: payload[:cached]
      },
      duration: payload[:runtime]
    )
  end

  # Controller action
  ActiveSupport::Notifications.subscribe("process_action.action_controller") do |_name, _start, _finish, _id, payload|
    add(
      type: "controller",
      name: "#{payload[:controller]}##{payload[:action]}",
      payload: {
        format: payload[:format],
        status: payload[:status],
        view_runtime: payload[:view_runtime]&.round(2),
        db_runtime: payload[:db_runtime]&.round(2)
      },
      duration: payload[:runtime]&.round(2)
    )
  end

  # Cache reads/writes
  ActiveSupport::Notifications.subscribe("cache_read.active_support") do |_name, _start, _finish, _id, payload|
    next unless payload[:hit]  # Only log cache hits

    add(
      type: "cache",
      name: "Cache read: #{payload[:key]}",
      payload: { hit: true, super: payload[:super] }
    )
  end

  ActiveSupport::Notifications.subscribe("cache_write.active_support") do |_name, _start, _finish, _id, payload|
    add(
      type: "cache",
      name: "Cache write: #{payload[:key]}",
      payload: { hit: false }
    )
  end

  # Active Job
  ActiveSupport::Notifications.subscribe("perform_start.active_job") do |_name, _start, _finish, _id, payload|
    add(
      type: "job",
      name: "Job started: #{payload[:job_class]}",
      payload: {
        job_id: payload[:job_id],
        queue: payload[:queue_name],
        arguments: payload[:arguments]&.first(200)
      }
    )
  end

  ActiveSupport::Notifications.subscribe("perform.active_job") do |_name, _start, _finish, _id, payload|
    add(
      type: "job",
      name: "Job completed: #{payload[:job_class]}",
      payload: {
        job_id: payload[:job_id],
        queue: payload[:queue_name],
        error: payload[:exception_object]&.message
      },
      duration: payload[:runtime]&.round(2)
    )
  end

  # Action Mailer
  ActiveSupport::Notifications.subscribe("deliver.action_mailer") do |_name, _start, _finish, _id, payload|
    add(
      type: "mailer",
      name: "Mail delivered: #{payload[:mailer]}##{payload[:message_id]}",
      payload: {
        mailer: payload[:mailer],
        message_id: payload[:message_id]
      }
    )
  end

  # Render partials
  ActiveSupport::Notifications.subscribe("render_partial.action_view") do |_name, _start, _finish, _id, payload|
    add(
      type: "render",
      name: "Render: #{payload[:identifier]}",
      payload: {
        cache_hits: payload[:cache_hit]
      },
      duration: payload[:duration]&.round(2)
    )
  end

  @subscribed = true
end

.subscribed? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/rails_nexus/breadcrumbs.rb', line 150

def subscribed?
  @subscribed
end