Module: TraceView::XTrace

Defined in:
lib/traceview/xtrace.rb

Overview

Methods to act on, manipulate or investigate an X-Trace value

Class Method Summary collapse

Class Method Details

.continue_service_context(start, finish) ⇒ Object

continue_service_context

In the case of service calls such as external HTTP requests, we pass along X-Trace headers so that request context can be maintained across servers and applications.

Remote requests can return a X-Trace header in which case we want to pickup on and continue the context in most cases.

if that be the case)



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# File 'lib/traceview/xtrace.rb', line 77

def continue_service_context(start, finish)
  if TraceView::XTrace.valid?(finish) && TraceView.tracing?

    # Assure that we received back a valid X-Trace with the same task_id
    if TraceView::XTrace.task_id(start) == TraceView::XTrace.task_id(finish)
      TraceView::Context.fromString(finish)
    else
      TraceView.logger.debug "Mismatched returned X-Trace ID: #{finish}"
    end
  end
end

.edge_id(xtrace) ⇒ Object

TraceView::XTrace.edge_id

Extract and return the edge_id portion of an X-Trace ID



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# File 'lib/traceview/xtrace.rb', line 52

def edge_id(xtrace)
  return nil unless TraceView::XTrace.valid?(xtrace)

  xtrace[42..57]
rescue StandardError => e
  TraceView.logger.debug e.message
  TraceView.logger.debug e.backtrace
  return nil
end

.task_id(xtrace) ⇒ Object

TraceView::XTrace.task_id

Extract and return the task_id portion of an X-Trace ID



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# File 'lib/traceview/xtrace.rb', line 37

def task_id(xtrace)
  return nil unless TraceView::XTrace.valid?(xtrace)

  xtrace[2..41]
rescue StandardError => e
  TraceView.logger.debug e.message
  TraceView.logger.debug e.backtrace
  return nil
end

.valid?(xtrace) ⇒ Boolean

TraceView::XTrace.valid?

Perform basic validation on a potential X-Trace ID

Returns:

  • (Boolean) 


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# File 'lib/traceview/xtrace.rb', line 15

def valid?(xtrace)
  # Shouldn't be nil
  return false unless xtrace

  # The X-Trace ID shouldn't be an initialized empty ID
  return false if (xtrace =~ /^1b0000000/i) == 0

  # Valid X-Trace IDs have a length of 58 bytes and start with '1b'
  return false unless xtrace.length == 58 && (xtrace =~ /^1b/i) == 0

  true
rescue StandardError => e
  TraceView.logger.debug e.message
  TraceView.logger.debug e.backtrace
  false
end