Class: ElasticAPM::OpenTracing::Tracer

Inherits:
Object
  • Object
show all
Defined in:
lib/elastic_apm/opentracing.rb

Overview

A custom tracer to use the OpenTracing API with ElasticAPM

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize ⇒ Tracer

Returns a new instance of Tracer.



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# File 'lib/elastic_apm/opentracing.rb', line 214

def initialize
  @scope_manager = ScopeManager.new
end

Instance Attribute Details

#scope_manager ⇒ Object (readonly)

Returns the value of attribute scope_manager.



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# File 'lib/elastic_apm/opentracing.rb', line 218

def scope_manager
  @scope_manager
end

Instance Method Details

#active_span ⇒ Object 



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# File 'lib/elastic_apm/opentracing.rb', line 220

def active_span
  scope_manager.active&.span
end

#extract(format, carrier) ⇒ Object 



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# File 'lib/elastic_apm/opentracing.rb', line 321

def extract(format, carrier)
  case format
  when ::OpenTracing::FORMAT_RACK
    SpanContext.from_header(
      carrier['HTTP_ELASTIC_APM_TRACEPARENT']
    )
  when ::OpenTracing::FORMAT_TEXT_MAP
    SpanContext.from_header(
      carrier['elastic-apm-traceparent']
    )
  else
    warn 'Only extraction from HTTP headers via Rack or in ' \
      'text map format are available'
    nil
  end
rescue ElasticAPM::TraceContext::InvalidTraceparentHeader
  nil
end

#inject(span_context, format, carrier) ⇒ Object

rubocop:enable Metrics/ParameterLists



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# File 'lib/elastic_apm/opentracing.rb', line 311

def inject(span_context, format, carrier)
  case format
  when ::OpenTracing::FORMAT_RACK, ::OpenTracing::FORMAT_TEXT_MAP
    carrier['elastic-apm-traceparent'] =
      span_context.traceparent.to_header
  else
    warn 'Only injection via HTTP headers and Rack is available'
  end
end

#start_active_span(operation_name, child_of: nil, references: nil, start_time: Time.now, tags: {}, ignore_active_scope: false, finish_on_close: true) ⇒ Object

rubocop:disable Metrics/ParameterLists



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# File 'lib/elastic_apm/opentracing.rb', line 225

def start_active_span(
  operation_name,
  child_of: nil,
  references: nil,
  start_time: Time.now,
  tags: {},
  ignore_active_scope: false,
  finish_on_close: true,
  **
)
  span = start_span(
    operation_name,
    child_of: child_of,
    references: references,
    start_time: start_time,
    tags: tags,
    ignore_active_scope: ignore_active_scope
  )
  scope = scope_manager.activate(span, finish_on_close: finish_on_close)

  if block_given?
    begin
      return yield scope
    ensure
      scope.close
    end
  end

  scope
end

#start_span(operation_name, child_of: nil, references: nil, start_time: Time.now, tags: {}, ignore_active_scope: false) ⇒ Object

rubocop:disable Metrics/ParameterLists



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# File 'lib/elastic_apm/opentracing.rb', line 258

def start_span(
  operation_name,
  child_of: nil,
  references: nil,
  start_time: Time.now,
  tags: {},
  ignore_active_scope: false,
  **
)
  span_context = prepare_span_context(
    child_of: child_of,
    references: references,
    ignore_active_scope: ignore_active_scope
  )

  if span_context
    trace_context =
      span_context.respond_to?(:trace_context) &&
      span_context.trace_context
  end

  elastic_span =
    if ElasticAPM.current_transaction
      ElasticAPM.start_span(
        operation_name,
        trace_context: trace_context
      )
    else
      ElasticAPM.start_transaction(
        operation_name,
        trace_context: trace_context
      )
    end

  # if no Elastic APM agent is running or transaction not sampled
  unless elastic_span
    return ::OpenTracing::Span::NOOP_INSTANCE
  end

  span_context ||=
    SpanContext.from_trace_context(elastic_span.trace_context)

  tags.each do |key, value|
    elastic_span.context.labels[key] = value
  end

  elastic_span.start Util.micros(start_time)

  Span.new(elastic_span, span_context)
end