Module: OneApm::Agent::CrossAppTracing

Defined in:
lib/one_apm/agent/cross_app/cross_app_tracing.rb

Defined Under Namespace

Classes: Error

Constant Summary collapse

OA_APPDATA_HEADER =

The cross app response header for “outgoing” calls

'X-BlueWare-App-Data'
OA_ID_HEADER =

The cross app id header for “outgoing” calls

'X-BlueWare-ID'
OA_TXN_HEADER =

The cross app transaction header for “outgoing” calls

'X-BlueWare-Transaction'
OA_SYNTHETICS_HEADER =

The cross app synthetics header

'X-BlueWare-Synthetics'
OA_APPDATA_TXN_GUID_INDEX =

The index of the transaction GUID in the appdata header of responses

5

Class Method Summary collapse

Class Method Details

.add_cat_transaction_trace_parameters(response) ⇒ Object

Extract any custom parameters from response if it’s cross-application and add them to the current TT node.



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# File 'lib/one_apm/agent/cross_app/cross_app_tracing.rb', line 223

def add_cat_transaction_trace_parameters( response )
  appdata = extract_appdata( response )
  transaction_sampler.add_segment_parameters( \
    :transaction_guid => appdata[OA_APPDATA_TXN_GUID_INDEX] )
end

.add_transaction_trace_parameters(request, response) ⇒ Object 



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# File 'lib/one_apm/agent/cross_app/cross_app_tracing.rb', line 213

def add_transaction_trace_parameters(request, response)
  filtered_uri = ::OneApm::Support::HTTPClients::URIUtil.filter_uri(request.uri)
  transaction_sampler.add_segment_parameters(:uri => filtered_uri)
  if response && response_is_crossapp?(response)
    add_cat_transaction_trace_parameters(response)
  end
end

.check_cross_tier_id(id) ⇒ Object 



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# File 'lib/one_apm/agent/cross_app/cross_app_tracing.rb', line 356

def check_cross_tier_id( id )
  id =~ /\A\d+#\d+#\d+\z/ or
    raise OneApm::Agent::CrossAppTracing::Error,
      "malformed cross application ID %p" % [ id ]
end

.check_crossapp_id(id) ⇒ Object

Check the given id to ensure it conforms to the format of a cross-application ID. Raises an OneApm::Agent::CrossAppTracing::Error if it doesn’t.



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# File 'lib/one_apm/agent/cross_app/cross_app_tracing.rb', line 350

def check_crossapp_id( id )
  id =~ /\A\d+#\d+\z/ or
    raise OneApm::Agent::CrossAppTracing::Error,
      "malformed cross application ID %p" % [ id ]
end

.check_transaction_name(name) ⇒ Object

Check the given name to ensure it conforms to the format of a valid transaction name.



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# File 'lib/one_apm/agent/cross_app/cross_app_tracing.rb', line 365

def check_transaction_name( name )
  # No-op -- apparently absolutely anything is a valid transaction name?
  # This is here for when that inevitably comes back to haunt us.
end

.common_metrics(request) ⇒ Object

Return an Array of metrics used for every response.



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# File 'lib/one_apm/agent/cross_app/cross_app_tracing.rb', line 256

def common_metrics( request )
  metrics = [ "External/all" ]
  metrics << "External/#{request.host}/all"

  if OneApm::Transaction.recording_web_transaction?
    metrics << "External/allWeb"
  else
    metrics << "External/allOther"
  end

  return metrics
end

.cross_app_enabled? ⇒ Boolean

Return true if cross app tracing is enabled in the config.

Returns:

  • (Boolean) 


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# File 'lib/one_apm/agent/cross_app/cross_app_tracing.rb', line 159

def cross_app_enabled?
  valid_cross_process_id? &&
    valid_encoding_key? &&
    cross_application_tracer_enabled?
end

.cross_app_encoding_key ⇒ Object

Fetcher for the cross app encoding key. Raises a OneApm::Agent::CrossAppTracing::Error if the key isn’t configured.



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# File 'lib/one_apm/agent/cross_app/cross_app_tracing.rb', line 179

def cross_app_encoding_key
  OneApm::Manager.config[:encoding_key] or
    raise OneApm::Agent::CrossAppTracing::Error, "No encoding_key set."
end

.cross_app_run_time_block(response, res_time) ⇒ Object 



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# File 'lib/one_apm/agent/cross_app/cross_app_tracing.rb', line 370

def cross_app_run_time_block response, res_time
  run_time_block = nil
  if response && response_is_crossapp?( response )
    xp_id, txn_name, _q_time, run_time, _req_len, _ = extract_appdata( response )
    run_time_block = Proc.new do |stats|  
      stats.call_count           += 1
      stats.total_call_time      += res_time
      stats.total_exclusive_time += run_time   
      stats.min_call_time        =  res_time
      stats.max_call_time        =  res_time
      stats.sum_of_squares       += res_time**2
      stats
    end
  end
  run_time_block
end

.cross_application_tracer_enabled? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/one_apm/agent/cross_app/cross_app_tracing.rb', line 173

def cross_application_tracer_enabled?
  OneApm::Manager.config[:"cross_application_tracer.enabled"]
end

.external_rename_rules ⇒ Object 



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# File 'lib/one_apm/agent/cross_app/cross_app_tracing.rb', line 344

def external_rename_rules
  OneApm::Manager.agent.external_rename_rules
end

.extract_appdata(response) ⇒ Object

Extract x-process application data from the specified response and return it as an array of the form:

[
  <cross app ID>,
  <transaction name>,
  <queue time in seconds>,
  <response time in seconds>,
  <request content length in bytes>,
  <transaction GUID>
]



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# File 'lib/one_apm/agent/cross_app/cross_app_tracing.rb', line 308

def extract_appdata( response )
  appdata = response[OA_APPDATA_HEADER] or
    raise OneApm::Agent::CrossAppTracing::Error,
      "Can't derive metrics for response: no #{OA_APPDATA_HEADER} header!"

  decoded_appdata = obfuscator.deobfuscate( appdata )
  decoded_appdata.set_encoding( ::Encoding::UTF_8 ) if
    decoded_appdata.respond_to?( :set_encoding )

  return OneApm::JSONWrapper.load( decoded_appdata )
end

.finish_trace(state, t0, segment, request, response) ⇒ Object

Finish tracing the HTTP request that started at t0 with the information in response and the given http connection.

The request must conform to the same interface described in the documentation for start_trace.

The response must respond to the following methods:

  • [](key) - Reads response headers.

  • to_hash - Converts response headers to a Hash



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# File 'lib/one_apm/agent/cross_app/cross_app_tracing.rb', line 98

def finish_trace(state, t0, segment, request, response)
  unless t0
    OneApm::Manager.logger.error("HTTP request trace finished without start time. This is probably an agent bug.")
    return
  end

  t1 = Time.now
  duration = t1.to_f - t0.to_f

  begin
    if request
      # Figure out which metrics we need to report based on the request and response
      # The last (most-specific) one is scoped.
      metrics = metrics_for(request, response)
      scoped_metric = metrics.pop

      #stats_engine.record_scoped_and_unscoped_metrics(state, scoped_metric, metrics, duration, nil, &cross_app_run_time_block(response, duration))
     
      # If we don't have segment, something failed during start_trace so
      # the current segment isn't the HTTP call it should have been.
      if segment
        segment.name = scoped_metric
        add_transaction_trace_parameters(request, response)
      end
      payload = {
          :name                            => name(request) ,
          :scope                           => state.current_transaction.frozen_name,
          :apdex_perf_zone                 => 'S',
          :guid                            => OneApm::Helper.generate_guid,
          :duration                        => duration,
          :referring_transaction_guid      => state.current_transaction.guid,
          :call_count                      => 1,
          :start_timestamp                 => t0.to_f,
          :request_url                     => request.uri,
          :bytes_sent                      => 0,
          :bytes_rec                       => 0,
          :has_trace                       => 0,
          :exec_time                       => duration,
          :call_type                       => 0
      }
      transaction_event_aggregator.on_cross_app_transaction_finished(payload)
    end
  ensure
    # If we have a segment, always pop the traced method stack to avoid
    # an inconsistent state, which prevents tracing of whole transaction.
    if segment
      stack = state.traced_method_stack
      stack.pop_frame(state, segment, scoped_metric, t1)
    end
  end
rescue OneApm::Agent::CrossAppTracing::Error => err
  OneApm::Manager.logger.debug "while cross app tracing", err
rescue => err
  OneApm::Manager.logger.error "Uncaught exception while finishing an HTTP request trace", err
end

.inject_request_headers(state, request) ⇒ Object

Inject the X-Process header into the outgoing request.



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# File 'lib/one_apm/agent/cross_app/cross_app_tracing.rb', line 189

def inject_request_headers(state, request)
  cross_app_id = OneApm::Manager.config[:cross_process_id] or
    raise OneApm::Agent::CrossAppTracing::Error, "no cross app ID configured"
  state.is_cross_app_caller = true
  txn_guid = state.request_guid
  txn = state.current_transaction
  if txn
    trip_id   = txn.cat_trip_id(state)
    path_hash = txn.cat_path_hash(state)
    request_host = request.host if request && request.respond_to?(:host)

    if txn.raw_synthetics_header
      request[OA_SYNTHETICS_HEADER] = txn.raw_synthetics_header
    end
  end
  txn_data  = OneApm::JSONWrapper.dump([txn_guid, true, trip_id, path_hash, request_host])

  request[OA_ID_HEADER]  = obfuscator.obfuscate(cross_app_id)
  request[OA_TXN_HEADER] = obfuscator.obfuscate(txn_data)

rescue OneApm::Agent::CrossAppTracing::Error => err
  OneApm::Manager.logger.debug "Not injecting x-process header", err
end

.metrics_for(request, response) ⇒ Object

Return the set of metric names that correspond to the given request and response. response may be nil in the case that the request produced an error without ever receiving an HTTP response.



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# File 'lib/one_apm/agent/cross_app/cross_app_tracing.rb', line 234

def metrics_for( request, response )
  metrics = common_metrics( request )

  if response && response_is_crossapp?( response )
    begin
      metrics.delete_if{|m| m == "External/#{request.host}/all"}
      metrics.concat metrics_for_crossapp_response( request, response )
    rescue => err
      # Fall back to regular metrics if there's a problem with x-process metrics
      OneApm::Manager.logger.debug "%p while fetching x-process metrics: %s" %
        [ err.class, err.message ]
      metrics.concat metrics_for_regular_request( request )
    end
  else
    metrics.concat metrics_for_regular_request( request )
  end

  return metrics
end

.metrics_for_crossapp_response(request, response) ⇒ Object

Return the set of metric objects appropriate for the given cross app response.



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# File 'lib/one_apm/agent/cross_app/cross_app_tracing.rb', line 284

def metrics_for_crossapp_response( request, response )
  xp_id, txn_name, _q_time, _r_time, _req_len, _ = extract_appdata( response )
  check_crossapp_id( xp_id )
  check_transaction_name( txn_name )

  metrics = []
  metrics << "ExternalApp/#{request.host}/#{xp_id}/all"
  metrics << "ExternalTransaction/#{request.host}/#{xp_id}/#{txn_name}"

  return metrics
end

.metrics_for_regular_request(request) ⇒ Object

Return the set of metric objects appropriate for the given (non-cross app) request.



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# File 'lib/one_apm/agent/cross_app/cross_app_tracing.rb', line 323

def metrics_for_regular_request( request )
  metrics = []
  metrics << "External/#{request.host}/#{request.type}/#{request.method}"

  return metrics
end

.name(request) ⇒ Object 



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# File 'lib/one_apm/agent/cross_app/cross_app_tracing.rb', line 154

def name(request)
  external_rename_rules.rename(request)
end

.obfuscator ⇒ Object 



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# File 'lib/one_apm/agent/cross_app/cross_app_tracing.rb', line 184

def obfuscator
  @obfuscator ||= OneApm::Agent::Obfuscator.new(cross_app_encoding_key)
end

.response_is_crossapp?(response) ⇒ Boolean

Returns true if Cross Application Tracing is enabled, and the given response has the appropriate headers.

Returns:

  • (Boolean) 


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# File 'lib/one_apm/agent/cross_app/cross_app_tracing.rb', line 272

def response_is_crossapp?( response )
  return false unless cross_app_enabled?
  unless response[OA_APPDATA_HEADER]
    return false
  end

  return true
end

.start_trace(state, t0, request) ⇒ Object

Set up the necessary state for cross-application tracing before the given request goes out.

The request object passed in must respond to the following methods:

  • type - Return a String describing the underlying library being used

    to make the request (e.g. 'Net::HTTP' or 'Typhoeus')

  • host - Return a String with the hostname or IP of the host being

    communicated with.

  • method - Return a String with the HTTP method name for this request

  • [](key) - Lookup an HTTP request header by name

  • []=(key, val) - Set an HTTP request header by name

  • uri - Full URI of the request

This method returns the transaction segment if it was sucessfully pushed.



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# File 'lib/one_apm/agent/cross_app/cross_app_tracing.rb', line 71

def start_trace(state, t0, request)
  inject_request_headers(state, request) if cross_app_enabled?
  stack = state.traced_method_stack
  segment = stack.push_frame(state, :http_request, t0)

  return segment
rescue => err
  OneApm::Manager.logger.error "Uncaught exception while tracing HTTP request", err
  return nil
rescue Exception => e
  OneApm::Manager.logger.debug "Unexpected exception raised while tracing HTTP request", e

  raise e
end

.stats_engine ⇒ Object

Fetch a reference to the stats engine.



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# File 'lib/one_apm/agent/cross_app/cross_app_tracing.rb', line 332

def stats_engine
  OneApm::Manager.agent.stats_engine
end

.tl_trace_http_request(request) ⇒ Object

Send the given request, adding metrics appropriate to the response when it comes back.

See the documentation for start_trace for an explanation of what request should look like.



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# File 'lib/one_apm/agent/cross_app/cross_app_tracing.rb', line 38

def tl_trace_http_request(request)
  state = OneApm::TransactionState.tl_get
  return yield unless state.is_execution_traced?
  return yield if request['_SKIP_CAT_']

  # It's important to set t0 outside the ensured block, otherwise there's
  # a race condition if we raise after begin but before t0's set.
  t0 = Time.now
  begin
    segment = start_trace(state, t0, request)
    response = yield
  ensure
    finish_trace(state, t0, segment, request, response)
  end

  return response
end

.transaction_event_aggregator ⇒ Object 



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# File 'lib/one_apm/agent/cross_app/cross_app_tracing.rb', line 340

def transaction_event_aggregator
  OneApm::Manager.agent.transaction_event_aggregator
end

.transaction_sampler ⇒ Object 



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# File 'lib/one_apm/agent/cross_app/cross_app_tracing.rb', line 336

def transaction_sampler
  OneApm::Manager.agent.transaction_sampler
end

.valid_cross_process_id? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/one_apm/agent/cross_app/cross_app_tracing.rb', line 165

def valid_cross_process_id?
  OneApm::Manager.config[:cross_process_id] && OneApm::Manager.config[:cross_process_id].length > 0
end

.valid_encoding_key? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/one_apm/agent/cross_app/cross_app_tracing.rb', line 169

def valid_encoding_key?
  OneApm::Manager.config[:encoding_key] && OneApm::Manager.config[:encoding_key].length > 0
end