Class: Oboe::Rack

Inherits:
Object
  • Object
show all
Defined in:
lib/oboe/inst/rack.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(app) ⇒ Rack

Returns a new instance of Rack.



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# File 'lib/oboe/inst/rack.rb', line 10

def initialize(app)
  @app = app
end

Instance Attribute Details

#app ⇒ Object (readonly)

Returns the value of attribute app.



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# File 'lib/oboe/inst/rack.rb', line 8

def app
  @app
end

Instance Method Details

#call(env) ⇒ Object 



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# File 'lib/oboe/inst/rack.rb', line 49

def call(env)
  rack_skipped = false

  # In the case of nested Ruby apps such as Grape inside of Rails
  # or Grape inside of Grape, each app has it's own instance
  # of rack middleware.  We avoid tracing rack more than once and
  # instead start instrumenting from the first rack pass.

  # If we're already tracing a rack layer, dont't start another one.
  if Oboe.tracing? && Oboe.layer == 'rack'
    rack_skipped = true
    Oboe.logger.debug "[oboe/rack] Rack skipped!"
    return @app.call(env)
  end

  req = ::Rack::Request.new(env)

  report_kvs = {}
  report_kvs[:URL] = URI.unescape(req.path)

  # Check for and validate X-Trace request header to pick up tracing context
  xtrace = env.is_a?(Hash) ? env['HTTP_X_TRACE'] : nil
  xtrace_header = xtrace if xtrace && Oboe::XTrace.valid?(xtrace)

  # Under JRuby, JOboe may have already started a trace.  Make note of this
  # if so and don't clear context on log_end (see oboe/api/logging.rb)
  Oboe.has_incoming_context = Oboe.tracing?
  Oboe.has_xtrace_header = xtrace_header
  Oboe.is_continued_trace = Oboe.has_incoming_context or Oboe.has_xtrace_header

  Oboe::API.log_start('rack', xtrace_header, report_kvs)

  # We only trace a subset of requests based off of sample rate so if
  # Oboe::API.log_start really did start a trace, we act accordingly here.
  if Oboe.tracing?
    report_kvs = collect(req, env)

    # We log an info event with the HTTP KVs found in Oboe::Rack.collect
    # This is done here so in the case of stacks that try/catch/abort
    # (looking at you Grape) we're sure the KVs get reported now as
    # this code may not be returned to later.
    Oboe::API.log_info('rack', report_kvs)

    status, headers, response = @app.call(env)

    xtrace = Oboe::API.log_end('rack', :Status => status)
  else
    status, headers, response = @app.call(env)
  end

  [status, headers, response]
rescue Exception => e
  unless rack_skipped
    Oboe::API.log_exception('rack', e)
    xtrace = Oboe::API.log_end('rack', :Status => 500)
  end
  raise
ensure
  if !rack_skipped && headers && Oboe::XTrace.valid?(xtrace)
    unless defined?(JRUBY_VERSION) && Oboe.is_continued_trace?
      headers['X-Trace'] = xtrace if headers.is_a?(Hash)
    end
  end
end

#collect(req, env) ⇒ Object 



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# File 'lib/oboe/inst/rack.rb', line 14

def collect(req, env)
  report_kvs = {}

  begin
    report_kvs['HTTP-Host']        = req.host
    report_kvs['Port']             = req.port
    report_kvs['Proto']            = req.scheme
    report_kvs['Query-String']     = URI.unescape(req.query_string) unless req.query_string.empty?
    report_kvs[:URL]               = URI.unescape(req.path)
    report_kvs[:Method]            = req.request_method
    report_kvs['AJAX']             = true if req.xhr?
    report_kvs['ClientIP']         = req.ip

    report_kvs['X-TV-Meta']         = env['HTTP_X_TV_META']          if env.key?('HTTP_X_TV_META')

    # Report any request queue'ing headers.  Report as 'Request-Start' or the summed Queue-Time
    report_kvs['Request-Start']     = env['HTTP_X_REQUEST_START']    if env.key?('HTTP_X_REQUEST_START')
    report_kvs['Request-Start']     = env['HTTP_X_QUEUE_START']      if env.key?('HTTP_X_QUEUE_START')
    report_kvs['Queue-Time']        = env['HTTP_X_QUEUE_TIME']       if env.key?('HTTP_X_QUEUE_TIME')

    report_kvs['Forwarded-For']     = env['HTTP_X_FORWARDED_FOR']    if env.key?('HTTP_X_FORWARDED_FOR')
    report_kvs['Forwarded-Host']    = env['HTTP_X_FORWARDED_HOST']   if env.key?('HTTP_X_FORWARDED_HOST')
    report_kvs['Forwarded-Proto']   = env['HTTP_X_FORWARDED_PROTO']  if env.key?('HTTP_X_FORWARDED_PROTO')
    report_kvs['Forwarded-Port']    = env['HTTP_X_FORWARDED_PORT']   if env.key?('HTTP_X_FORWARDED_PORT')

    report_kvs['Ruby.Oboe.Version'] = ::Oboe::Version::STRING
    report_kvs['ProcessID']         = Process.pid
    report_kvs['ThreadID']          = Thread.current.to_s[/0x\w*/]
  rescue StandardError => e
    # Discard any potential exceptions. Debug log and report whatever we can.
    Oboe.logger.debug "[oboe/debug] Rack KV collection error: #{e.inspect}"
  end
  report_kvs
end