Module: TraceView::API::Logging

Defined in:
lib/traceview/api/logging.rb

Overview

This modules provides the X-Trace logging facilities.

Instance Method Summary collapse

Instance Method Details

#log(layer, label, opts = {}) ⇒ Object

Public: Report an event in an active trace.

layer - The layer the reported event belongs to label - The label for the reported event. See API documentation for

reserved labels and usage.

opts - A hash containing key/value pairs that will be reported along

with this event (optional).

Example

log('logical_layer', 'entry')
log('logical_layer', 'info', { :list_length => 20 })
log('logical_layer', 'exit')

Returns nothing.



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# File 'lib/traceview/api/logging.rb', line 24

def log(layer, label, opts = {})
  if TraceView.loaded
    log_event(layer, label, TraceView::Context.createEvent, opts)
  end
end

#log_end(layer, opts = {}) ⇒ Object

Public: Report an exit event.

layer - The layer the reported event belongs to

Returns an xtrace metadata string



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# File 'lib/traceview/api/logging.rb', line 108

def log_end(layer, opts = {})
  if TraceView.loaded
    log_event(layer, 'exit', TraceView::Context.createEvent, opts)
    xtrace = TraceView::Context.toString
    TraceView::Context.clear unless TraceView.has_incoming_context?
    xtrace
  end
end

#log_entry(layer, kvs = {}, op = nil) ⇒ Object

Public: Log an entry event

A helper method to create and log an entry event

Returns an xtrace metadata string



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# File 'lib/traceview/api/logging.rb', line 124

def log_entry(layer, kvs = {}, op = nil)
  if TraceView.loaded
    TraceView.layer_op = op if op
    log_event(layer, 'entry', TraceView::Context.createEvent, kvs)
  end
end

#log_event(layer, label, event, opts = {}) ⇒ Object

Internal: Report an event.

layer - The layer the reported event belongs to label - The label for the reported event. See API documentation for

reserved labels and usage.

opts - A hash containing key/value pairs that will be reported along

with this event (optional).

Examples

entry = TraceView::Context.createEvent
log_event('rails', 'entry', exit, { :controller => 'user', :action => 'index' })
exit = TraceView::Context.createEvent
exit.addEdge(entry.getMetadata)
log_event('rails', 'exit', exit)

Returns nothing.



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# File 'lib/traceview/api/logging.rb', line 175

def log_event(layer, label, event, opts = {})
  if TraceView.loaded
    event.addInfo('Layer', layer.to_s) if layer
    event.addInfo('Label', label.to_s)

    TraceView.layer = layer if label == 'entry'
    TraceView.layer = nil   if label == 'exit'

    opts.each do |k, v|
      value = nil

      if valid_key? k
        if [Integer, Float, Fixnum, NilClass, String].include?(v.class)
          value = v
        elsif v.class == Set
          value = v.to_a.to_s
        else
          value = v.to_s if v.respond_to?(:to_s)
        end

        begin
          event.addInfo(k.to_s, value)
        rescue ArgumentError => e
          TraceView.logger.debug "[TraceView/debug] Couldn't add event KV: #{k.to_s} => #{v.class}"
          TraceView.logger.debug "[TraceView/debug] #{e.message}"
        end
      end
    end if !opts.nil? && opts.any?

    TraceView::Reporter.sendReport(event)
  end
end

#log_exception(layer, exn) ⇒ Object

Public: Report an exception.

layer - The layer the reported event belongs to exn - The exception to report

Example

begin
  function_without_traceview()
rescue Exception => e
  log_exception('rails', e)
  raise
end

Returns nothing.



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# File 'lib/traceview/api/logging.rb', line 45

def log_exception(layer, exn)
  return if !TraceView.loaded || exn.instance_variable_get(:@oboe_logged)

  kvs = { :ErrorClass => exn.class.name,
          :ErrorMsg => exn.message,
          :Backtrace => exn.backtrace.join("\r\n") }

  exn.instance_variable_set(:@oboe_logged, true)
  log(layer, 'error', kvs)
end

#log_exit(layer, kvs = {}, op = nil) ⇒ Object

Public: Log an exit event

A helper method to create and log an exit event

Returns an xtrace metadata string



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# File 'lib/traceview/api/logging.rb', line 151

def log_exit(layer, kvs = {}, op = nil)
  if TraceView.loaded
    TraceView.layer_op = nil if op
    log_event(layer, 'exit', TraceView::Context.createEvent, kvs)
  end
end

#log_info(layer, kvs = {}) ⇒ Object

Public: Log an info event

A helper method to create and log an info event

Returns an xtrace metadata string



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# File 'lib/traceview/api/logging.rb', line 138

def log_info(layer, kvs = {})
  if TraceView.loaded
    log_event(layer, 'info', TraceView::Context.createEvent, kvs)
  end
end

#log_start(layer, xtrace = nil, opts = {}) ⇒ Object

Public: Decide whether or not to start a trace, and report an event appropriately.

layer - The layer the reported event belongs to xtrace - An xtrace metadata string, or nil. opts - A hash containing key/value pairs that will be reported along

with this event (optional).

Returns nothing.



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# File 'lib/traceview/api/logging.rb', line 65

def log_start(layer, xtrace = nil, opts = {})
  return if !TraceView.loaded || TraceView.never? ||
            (opts.key?(:URL) && ::TraceView::Util.static_asset?(opts[:URL]))

  TraceView::Context.fromString(xtrace) if TraceView.pickup_context?(xtrace)

  if TraceView.tracing?
    # Pre-existing context.  Either we inherited context from an
    # incoming X-Trace request header or under JRuby, Joboe started
    # tracing before the JRuby code was called (e.g. Tomcat)
    TraceView.is_continued_trace = true

    if TraceView.has_xtrace_header
      opts[:TraceOrigin] = :continued_header
    elsif TraceView.has_incoming_context
      opts[:TraceOrigin] = :continued_context
    else
      opts[:TraceOrigin] = :continued
    end

    log_entry(layer, opts)

  elsif opts.key?('Force')
    # Forced tracing: used by __Init reporting
    opts[:TraceOrigin] = :forced
    log_event(layer, 'entry', TraceView::Context.startTrace, opts)

  elsif TraceView.sample?(opts.merge(:layer => layer, :xtrace => xtrace))
    # Probablistic tracing of a subset of requests based off of
    # sample rate and sample source
    opts[:SampleRate]        = TraceView.sample_rate
    opts[:SampleSource]      = TraceView.sample_source
    opts[:TraceOrigin] = :always_sampled

    log_event(layer, 'entry', TraceView::Context.startTrace, opts)
  end
end