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

Class Method Summary collapse

Class Method Details

.flush ⇒ Object 



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# File 'lib/errorgap/span_collector.rb', line 55

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

  ActiveSupport::Notifications.subscribe("sql.active_record") do |*, payload|
    next unless Thread.current[THREAD_KEY]
    next if SKIP_NAMES.any? { |n| payload[:name]&.start_with?(n) }
    next if payload[:cached]

    duration_ms = payload[:duration] || 0.0
    sql = normalize_sql(payload[:sql].to_s)

    store << Span.new(kind: "db", sql: sql, 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 65

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 51

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

.store ⇒ Object 



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# File 'lib/errorgap/span_collector.rb', line 61

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