Class: LightStep::Span

Inherits:
Object
  • Object
show all
Defined in:
lib/lightstep/span.rb

Overview

Span represents an OpenTracer Span

See www.opentracing.io for more information.

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(tracer:, operation_name:, child_of: nil, references: [], start_micros:, tags: nil, max_log_records:) ⇒ Span

Creates a new LightStep::Span

Parameters:

  • the tracer that created this span

  • the operation name of this span. If it’s not a String it will be encoded with to_s.

  • (defaults to: nil)

    the parent SpanContext (per child_of)

  • (defaults to: [])

    An array of SpanContexts that identify what Spans this Span follows from causally. Presently only one reference is supported, and cannot be provided in addition to a child_of.

  • start time of the span in microseconds

  • (defaults to: nil)

    initial key:value tags (per set_tag) for the Span

  • maximum allowable number of log records for the Span



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# File 'lib/lightstep/span.rb', line 31

def initialize(
  tracer:,
  operation_name:,
  child_of: nil,
  references: [],
  start_micros:,
  tags: nil,
  max_log_records:
)
  @tags = Concurrent::Hash.new
  @tags.update(tags) unless tags.nil?
  @log_records = Concurrent::Array.new
  @dropped_logs = Concurrent::AtomicFixnum.new
  @max_log_records = max_log_records

  @tracer = tracer
  self.operation_name = operation_name.to_s
  self.start_micros = start_micros

  ref = child_of ? child_of : references
  ref = ref[0] if (Array === ref)
  ref = ref.span_context if (Span === ref)

  if SpanContext === ref
    @span_context = SpanContext.new(id: LightStep.guid, trace_id: ref.trace_id)
    set_baggage(ref.baggage)
    set_tag(:parent_span_guid, ref.id)
  else
    @span_context = SpanContext.new(id: LightStep.guid, trace_id: LightStep.guid)
  end
end

Instance Attribute Details

#end_micros ⇒ Object

Internal use only



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# File 'lib/lightstep/span.rb', line 14

def end_micros
  @end_micros
end

#operation_name ⇒ Object

Internal use only



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# File 'lib/lightstep/span.rb', line 14

def operation_name
  @operation_name
end

#span_context ⇒ Object (readonly)

Internal use only



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# File 'lib/lightstep/span.rb', line 14

def span_context
  @span_context
end

#start_micros ⇒ Object

Internal use only



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# File 'lib/lightstep/span.rb', line 14

def start_micros
  @start_micros
end

#tags ⇒ Object (readonly)

Internal use only



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# File 'lib/lightstep/span.rb', line 14

def tags
  @tags
end

Instance Method Details

#dropped_logs_count ⇒ Object

Internal use only



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# File 'lib/lightstep/span.rb', line 159

def dropped_logs_count
  dropped_logs.value
end

#finish(end_time: Time.now) ⇒ Object

Finish the LightStep::Span

Parameters:

  • (defaults to: Time.now)

    custom end time, if not now



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# File 'lib/lightstep/span.rb', line 131

def finish(end_time: Time.now)
  if end_micros.nil?
    self.end_micros = LightStep.micros(end_time)
  end
  tracer.finish_span(self)
  self
end

#get_baggage_item(key) ⇒ Object

Get a baggage item

Parameters:

  • the key of the baggage item

Returns:

  • Value of the baggage item



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# File 'lib/lightstep/span.rb', line 100

def get_baggage_item(key)
  span_context.baggage[key]
end

#log(event: nil, timestamp: Time.now, **fields) ⇒ Object

Add a log entry to this span

Parameters:

  • (defaults to: nil)

    event name for the log

  • (defaults to: Time.now)

    time of the log

  • Additional information to log



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# File 'lib/lightstep/span.rb', line 108

def log(event: nil, timestamp: Time.now, **fields)
  return unless tracer.enabled?

  fields = {} if fields.nil?
  unless event.nil?
  fields[:event] = event.to_s
  end
  record = {
    timestamp_micros: LightStep.micros(timestamp),
    fields: fields.to_a.map {|key, value|
      {Key: key.to_s, Value: value.to_s}
    },
  }

  log_records.push(record)
  if log_records.size > @max_log_records
    log_records.shift
    dropped_logs.increment
  end
end

#logs_count ⇒ Object

Internal use only



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# File 'lib/lightstep/span.rb', line 165

def logs_count
  log_records.size
end

#set_baggage(baggage = {}) ⇒ Object

Set all baggage at once. This will reset the baggage to the given param.

Parameters:

  • (defaults to: {})

    new baggage for the span



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# File 'lib/lightstep/span.rb', line 89

def set_baggage(baggage = {})
  @span_context = SpanContext.new(
    id: span_context.id,
    trace_id: span_context.trace_id,
    baggage: baggage
  )
end

#set_baggage_item(key, value) ⇒ Object

Set a baggage item on the span

Parameters:

  • the key of the baggage item

  • the value of the baggage item



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# File 'lib/lightstep/span.rb', line 78

def set_baggage_item(key, value)
  @span_context = SpanContext.new(
    id: span_context.id,
    trace_id: span_context.trace_id,
    baggage: span_context.baggage.merge({key => value})
  )
  self
end

#set_tag(key, value) ⇒ Object

Set a tag value on this span it will be encoded with to_s

Parameters:

  • the key of the tag

  • the value of the tag. If it’s not a String



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# File 'lib/lightstep/span.rb', line 67

def set_tag(key, value)
  tags[key] = value.to_s
  self
end

#to_h ⇒ Object

Hash representation of a span



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# File 'lib/lightstep/span.rb', line 140

def to_h
  {
    runtime_guid: tracer.guid,
    span_guid: span_context.id,
    trace_guid: span_context.trace_id,
    span_name: operation_name,
    attributes: tags.map {|key, value|
      {Key: key.to_s, Value: value}
    },
    oldest_micros: start_micros,
    youngest_micros: end_micros,
    error_flag: false,
    dropped_logs: dropped_logs_count,
    log_records: log_records
  }
end