Class: Errorgap::SpanCollector

Inherits:
Object
  • Object
show all
Defined in:
lib/errorgap/span_collector.rb

Constant Summary collapse

THREAD_KEY = 
:errorgap_spans
NORMALIZE_PATTERN =

Quoted strings and standalone numeric literals → ?

/
  '(?:[^'\\]|\\.)*'   # single-quoted string literals
  |
  \b\d+(?:\.\d+)?\b   # integer and float literals
/x
SKIP_NAMES = 
%w[SCHEMA EXPLAIN CACHE].freeze
LIB_ROOT = 
File.expand_path("..", __dir__)
GEM_PATH_MARKERS = 
["/gems/", "/rubygems/", "/lib/ruby/", "/bundler/"].freeze

Class Method Summary collapse

Class Method Details

.app_call_site ⇒ Object

The first backtrace frame belonging to the application — skipping this gem, other gems, and the Ruby standard library — so a query can be attributed to the app code that ran it. Returns [file, line, fn_name] with the file relative to Rails.root when available, or nils when no app frame is present (e.g. queries run from a console or gem).



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# File 'lib/errorgap/span_collector.rb', line 81

def app_call_site
  root = defined?(Rails) && Rails.respond_to?(:root) && Rails.root ? Rails.root.to_s : nil
  location = caller_locations(1, 60)&.find do |loc|
    path = loc.absolute_path || loc.path
    next false unless path
    next false if path.start_with?(LIB_ROOT)
    next false if GEM_PATH_MARKERS.any? { |marker| path.include?(marker) }

    root ? path.start_with?(root) : true
  end
  return [nil, nil, nil] unless location

  path = location.absolute_path || location.path
  path = path.delete_prefix("#{root}/") if root
  [path, location.lineno, location.label]
end

.flush ⇒ Object 



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# File 'lib/errorgap/span_collector.rb', line 62

def flush
  spans = Thread.current[THREAD_KEY] || []
  Thread.current[THREAD_KEY] = nil
  spans
end

.install ⇒ Object

Call once at boot (from Railtie). Subscribers only record while a transaction is being collected (the middleware starts one per request when APM is enabled), so installing unconditionally is safe — and required, since app initializers that enable APM run after railtie initializers.



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# File 'lib/errorgap/span_collector.rb', line 22

def install
  return unless defined?(ActiveSupport::Notifications)
  return if @installed

  @installed = true

  # The 5-arg block form receives the event's start/finish times; the
  # sql.active_record payload itself carries no duration key.
  ActiveSupport::Notifications.subscribe("sql.active_record") do |_name, started, finished, _id, payload|
    next unless Thread.current[THREAD_KEY]
    next if SKIP_NAMES.any? { |n| payload[:name]&.start_with?(n) }
    next if payload[:cached]

    duration_ms = ((finished - started) * 1000.0).to_f
    sql = normalize_sql(payload[:sql].to_s)
    file, line, fn_name = app_call_site

    store << Span.new(
      kind: "db", sql: sql,
      file: file, line: line, fn_name: fn_name,
      duration_ms: duration_ms.round(3)
    )
  end

  # Rails reports view_runtime with database time already subtracted, so
  # this does not double count the db spans above.
  ActiveSupport::Notifications.subscribe("process_action.action_controller") do |*, payload|
    next unless Thread.current[THREAD_KEY]

    view_ms = payload[:view_runtime]
    next unless view_ms&.positive?

    store << Span.new(kind: "view", duration_ms: view_ms.round(3))
  end
end

.normalize_sql(sql) ⇒ Object 



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# File 'lib/errorgap/span_collector.rb', line 72

def normalize_sql(sql)
  sql.gsub(NORMALIZE_PATTERN, "?").gsub(/\s+/, " ").strip
end

.start ⇒ Object 



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# File 'lib/errorgap/span_collector.rb', line 58

def start
  Thread.current[THREAD_KEY] = []
end

.store ⇒ Object 



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# File 'lib/errorgap/span_collector.rb', line 68

def store
  Thread.current[THREAD_KEY] ||= []
end