Class: AppMap::Middleware::RemoteRecording

Inherits:
Object
  • Object
show all
Defined in:
lib/appmap/middleware/remote_recording.rb

Overview

RemoteRecording adds ‘/_appmap/record` routes to control recordings via HTTP requests. It can also be enabled to emit an AppMap for each request.

Instance Method Summary collapse

Constructor Details

#initialize(app) ⇒ RemoteRecording

Returns a new instance of RemoteRecording.



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# File 'lib/appmap/middleware/remote_recording.rb', line 8

def initialize(app)
  require "json"

  @app = app
end

Instance Method Details

#call(env) ⇒ Object 



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# File 'lib/appmap/middleware/remote_recording.rb', line 79

def call(env)
  # Note: Puma config is avaliable here. For example:
  # $ env['puma.config'].final_options[:workers]
  # 0

  req = Rack::Request.new(env)
  return handle_record_request(req) if AppMap.recording_enabled?(:remote) && req.path == "/_appmap/record"

  start_time = Time.now
  # Support multi-threaded web server such as Puma by recording each thread
  # into a separate Tracer.
  tracer = AppMap.tracing.trace(thread: Thread.current) if record_all_requests?

  record_request = lambda do |args|
    return unless tracer

    AppMap.tracing.delete(tracer)

    status, headers = args
    events = tracer.events.map(&:to_h)

    event_fields = events.map(&:keys).flatten.map(&:to_sym).uniq.sort
    return unless %i[http_server_request http_server_response].all? { |field| event_fields.include?(field) }

    path = req.path.gsub(/\/{2,}/, "/") # Double slashes have been observed
    appmap_name = "#{req.request_method} #{path} (#{status}) - #{start_time.strftime("%T.%L")}"
    appmap_file_name = AppMap::Util.scenario_filename([start_time.to_f, req.url].join("_"))
    output_dir = File.join(AppMap.output_dir, "requests")
    appmap_file_path = File.join(output_dir, appmap_file_name)

    metadata = AppMap.detect_metadata
    metadata[:name] = appmap_name
    metadata[:recorder] = {
      name: "rack",
      type: "requests"
    }

    appmap = {
      version: AppMap::APPMAP_FORMAT_VERSION,
      classMap: AppMap.class_map(tracer.event_methods),
      metadata: metadata,
      events: events
    }

    FileUtils.mkdir_p(output_dir)
    File.write(appmap_file_path, JSON.generate(appmap))

    headers["AppMap-Name"] = File.expand_path(appmap_name)
    headers["AppMap-File-Name"] = File.expand_path(appmap_file_path)
  end

  @app.call(env).tap(&record_request)
end

#event_loop ⇒ Object 



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# File 'lib/appmap/middleware/remote_recording.rb', line 14

def event_loop
  loop do
    event = @tracer.next_event if @tracer
    if event
      @events << event.to_h
    else
      sleep 0.0001
    end
  end
end

#handle_record_request(req) ⇒ Object 



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# File 'lib/appmap/middleware/remote_recording.rb', line 137

def handle_record_request(req)
  method = req.env["REQUEST_METHOD"]

  status, body = \
    if method.eql?("GET")
      recording_state
    elsif method.eql?("POST")
      ws_start_recording
    elsif method.eql?("DELETE")
      ws_stop_recording(req)
    else
      [404, ""]
    end

  [status, {"Content-Type" => "application/json"}, [body || ""]]
end

#html_response?(headers) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/appmap/middleware/remote_recording.rb', line 154

def html_response?(headers)
  headers["Content-Type"] && headers["Content-Type"] =~ /html/
end

#record_all_requests? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/appmap/middleware/remote_recording.rb', line 158

def record_all_requests?
  AppMap.recording_enabled?(:requests)
end

#recording? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/appmap/middleware/remote_recording.rb', line 162

def recording?
  !@event_thread.nil?
end

#recording_state ⇒ Object 



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# File 'lib/appmap/middleware/remote_recording.rb', line 133

def recording_state
  [200, JSON.generate({enabled: recording?})]
end

#ws_start_recording ⇒ Object 



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# File 'lib/appmap/middleware/remote_recording.rb', line 25

def ws_start_recording
  return [409, "Recording is already in progress"] if @tracer

  @events = []
  @tracer = AppMap.tracing.trace
  @event_thread = Thread.new { event_loop }
  @event_thread.abort_on_exception = true

  [200]
end

#ws_stop_recording(req) ⇒ Object 



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# File 'lib/appmap/middleware/remote_recording.rb', line 36

def ws_stop_recording(req)
  return [404, "No recording is in progress"] unless @tracer

  tracer = @tracer
  @tracer = nil

  AppMap.tracing.delete(tracer)

  @event_thread.exit
  @event_thread.join
  @event_thread = nil

  # Delete the events which are calls to or returns from the URL path _appmap/record
  # because these are not of interest to the user.
  is_control_command_event = lambda do |event|
    event[:event] == :call &&
      event[:http_server_request] &&
      event[:http_server_request][:path_info] == "/_appmap/record"
  end
  control_command_events = @events.select(&is_control_command_event)

  is_return_from_control_command_event = lambda do |event|
    event[:parent_id] && control_command_events.find { |e| e[:id] == event[:parent_id] }
  end

  @events.delete_if(&is_control_command_event)
  @events.delete_if(&is_return_from_control_command_event)

  metadata = AppMap.detect_metadata
  metadata[:recorder] = {
    name: "remote_recording",
    type: "remote"
  }

  response = JSON.generate \
    version: AppMap::APPMAP_FORMAT_VERSION,
    classMap: AppMap.class_map(tracer.event_methods),
    metadata: metadata,
    events: @events

  [200, response]
end