Class: Datadog::Tracing::TraceOperation

Inherits:
Object
  • Object
show all
Includes:
Metadata::Tagging
Defined in:
lib/datadog/tracing/trace_operation.rb

Overview

Represents the act of tracing a series of operations, by generating and collecting span measurements. When completed, it yields a trace.

Supports synchronous code flow only. Usage across multiple threads will result in incorrect relationships. For async support, a TraceOperation should be employed per execution context (e.g. Thread, etc.)

Constant Summary collapse

DEFAULT_MAX_LENGTH = 
100_000

Constants included from Metadata::Tagging

Metadata::Tagging::ENSURE_AGENT_TAGS, Metadata::Tagging::NUMERIC_TAG_SIZE_RANGE

Instance Attribute Summary collapse

Instance Method Summary collapse

Methods included from Metadata::Tagging

#clear_metric, #clear_tag, #get_metric, #get_tag, #has_tag?, #set_metric, #set_tag, #set_tags

Constructor Details

#initialize(agent_sample_rate: nil, events: nil, hostname: nil, id: nil, max_length: DEFAULT_MAX_LENGTH, name: nil, origin: nil, parent_span_id: nil, rate_limiter_rate: nil, resource: nil, rule_sample_rate: nil, sample_rate: nil, sampled: nil, sampling_priority: nil, service: nil, tags: nil, metrics: nil) ⇒ TraceOperation

Returns a new instance of TraceOperation.



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# File 'lib/datadog/tracing/trace_operation.rb', line 54

def initialize(
  agent_sample_rate: nil,
  events: nil,
  hostname: nil,
  id: nil,
  max_length: DEFAULT_MAX_LENGTH,
  name: nil,
  origin: nil,
  parent_span_id: nil,
  rate_limiter_rate: nil,
  resource: nil,
  rule_sample_rate: nil,
  sample_rate: nil,
  sampled: nil,
  sampling_priority: nil,
  service: nil,
  tags: nil,
  metrics: nil
)
  # Attributes
  @id = id || Tracing::Utils.next_id
  @max_length = max_length || DEFAULT_MAX_LENGTH
  @parent_span_id = parent_span_id
  @sampled = sampled.nil? ? true : sampled

  # Tags
  @agent_sample_rate = agent_sample_rate
  @hostname = hostname
  @name = name
  @origin = origin
  @rate_limiter_rate = rate_limiter_rate
  @resource = resource
  @rule_sample_rate = rule_sample_rate
  @sample_rate = sample_rate
  @sampling_priority = sampling_priority
  @service = service

  # Generic tags
  set_tags(tags) if tags
  set_tags(metrics) if metrics

  # State
  @root_span = nil
  @active_span = nil
  @active_span_count = 0
  @events = events || Events.new
  @finished = false
  @spans = []
end

Instance Attribute Details

#active_span ⇒ Object (readonly)

Returns the value of attribute active_span.



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# File 'lib/datadog/tracing/trace_operation.rb', line 41

def active_span
  @active_span
end

#active_span_count ⇒ Object (readonly)

Returns the value of attribute active_span_count.



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# File 'lib/datadog/tracing/trace_operation.rb', line 41

def active_span_count
  @active_span_count
end

#agent_sample_rate ⇒ Object

Returns the value of attribute agent_sample_rate.



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# File 'lib/datadog/tracing/trace_operation.rb', line 32

def agent_sample_rate
  @agent_sample_rate
end

#hostname ⇒ Object

Returns the value of attribute hostname.



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# File 'lib/datadog/tracing/trace_operation.rb', line 32

def hostname
  @hostname
end

#id ⇒ Object (readonly)

Returns the value of attribute id.



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# File 'lib/datadog/tracing/trace_operation.rb', line 41

def id
  @id
end

#max_length ⇒ Object (readonly)

Returns the value of attribute max_length.



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# File 'lib/datadog/tracing/trace_operation.rb', line 41

def max_length
  @max_length
end

#name ⇒ Object 



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# File 'lib/datadog/tracing/trace_operation.rb', line 146

def name
  @name || (root_span && root_span.name)
end

#origin ⇒ Object

Returns the value of attribute origin.



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# File 'lib/datadog/tracing/trace_operation.rb', line 32

def origin
  @origin
end

#parent_span_id ⇒ Object (readonly)

Returns the value of attribute parent_span_id.



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# File 'lib/datadog/tracing/trace_operation.rb', line 41

def parent_span_id
  @parent_span_id
end

#rate_limiter_rate ⇒ Object

Returns the value of attribute rate_limiter_rate.



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# File 'lib/datadog/tracing/trace_operation.rb', line 32

def rate_limiter_rate
  @rate_limiter_rate
end

#resource ⇒ Object 



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# File 'lib/datadog/tracing/trace_operation.rb', line 150

def resource
  @resource || (root_span && root_span.resource)
end

#rule_sample_rate ⇒ Object

Returns the value of attribute rule_sample_rate.



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# File 'lib/datadog/tracing/trace_operation.rb', line 32

def rule_sample_rate
  @rule_sample_rate
end

#sample_rate ⇒ Object

Returns the value of attribute sample_rate.



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# File 'lib/datadog/tracing/trace_operation.rb', line 32

def sample_rate
  @sample_rate
end

#sampled=(value) ⇒ Object (writeonly)

Sets the attribute sampled

Parameters:

  • value —

    the value to set the attribute sampled to.



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# File 'lib/datadog/tracing/trace_operation.rb', line 48

def sampled=(value)
  @sampled = value
end

#sampling_priority ⇒ Object

Returns the value of attribute sampling_priority.



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# File 'lib/datadog/tracing/trace_operation.rb', line 32

def sampling_priority
  @sampling_priority
end

#service ⇒ Object 



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# File 'lib/datadog/tracing/trace_operation.rb', line 161

def service
  @service || (root_span && root_span.service)
end

Instance Method Details

#build_span(op_name, events: nil, on_error: nil, resource: nil, service: nil, start_time: nil, tags: nil, type: nil) ⇒ Object 



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# File 'lib/datadog/tracing/trace_operation.rb', line 197

def build_span(
  op_name,
  events: nil,
  on_error: nil,
  resource: nil,
  service: nil,
  start_time: nil,
  tags: nil,
  type: nil
)
  begin
    # Resolve span options:
    # Parent, service name, etc.
    # Add default options
    trace_id = @id
    parent = @active_span

    # Use active span's span ID if available. Otherwise, the parent span ID.
    # Necessary when this trace continues from another, e.g. distributed trace.
    parent_id = parent ? parent.id : @parent_span_id || 0

    # Build events
    events ||= SpanOperation::Events.new

    # Before start: activate the span, publish events.
    events.before_start.subscribe do |span_op|
      start_span(span_op)
    end

    # After finish: deactivate the span, record, publish events.
    events.after_finish.subscribe do |span, span_op|
      finish_span(span, span_op, parent)
    end

    # Build a new span operation
    SpanOperation.new(
      op_name,
      events: events,
      on_error: on_error,
      parent_id: parent_id,
      resource: resource || op_name,
      service: service,
      start_time: start_time,
      tags: tags,
      trace_id: trace_id,
      type: type
    )
  rescue StandardError => e
    Datadog.logger.debug { "Failed to build new span: #{e}" }

    # Return dummy span
    SpanOperation.new(op_name)
  end
end

#finished? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/datadog/tracing/trace_operation.rb', line 112

def finished?
  @finished == true
end

#finished_span_count ⇒ Object 



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# File 'lib/datadog/tracing/trace_operation.rb', line 108

def finished_span_count
  @spans.length
end

#flush! {|spans| ... } ⇒ TraceSegment

Returns a Datadog::Tracing::TraceSegment with all finished spans that can be flushed at invocation time. All other finished spans are discarded.

Yields:

  • (spans) —

    spans that will be returned as part of the trace segment returned

Returns:



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# File 'lib/datadog/tracing/trace_operation.rb', line 257

def flush!
  finished = finished?

  # Copy out completed spans
  spans = @spans.dup
  @spans = []

  spans = yield(spans) if block_given?

  # Use them to build a trace
  build_trace(spans, !finished)
end

#fork_clone ⇒ Object

Returns a copy of this trace suitable for forks (w/o spans.) Used for continuation of traces across forks.



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# File 'lib/datadog/tracing/trace_operation.rb', line 299

def fork_clone
  self.class.new(
    agent_sample_rate: @agent_sample_rate,
    events: (@events && @events.dup),
    hostname: (@hostname && @hostname.dup),
    id: @id,
    max_length: @max_length,
    name: (name && name.dup),
    origin: (@origin && @origin.dup),
    parent_span_id: (@active_span && @active_span.id) || @parent_span_id,
    rate_limiter_rate: @rate_limiter_rate,
    resource: (resource && resource.dup),
    rule_sample_rate: @rule_sample_rate,
    sample_rate: @sample_rate,
    sampled: @sampled,
    sampling_priority: @sampling_priority,
    service: (service && service.dup),
    tags: meta.dup,
    metrics: metrics.dup
  )
end

#full? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/datadog/tracing/trace_operation.rb', line 104

def full?
  @max_length > 0 && @active_span_count >= @max_length
end

#keep! ⇒ Object 



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# File 'lib/datadog/tracing/trace_operation.rb', line 134

def keep!
  self.sampled = true
  self.sampling_priority = Sampling::Ext::Priority::USER_KEEP
  set_tag(Tracing::Metadata::Ext::Distributed::TAG_DECISION_MAKER, Tracing::Sampling::Ext::Decision::MANUAL)
end

#measure(op_name, events: nil, on_error: nil, resource: nil, service: nil, start_time: nil, tags: nil, type: nil, &block) ⇒ Object 



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# File 'lib/datadog/tracing/trace_operation.rb', line 165

def measure(
  op_name,
  events: nil,
  on_error: nil,
  resource: nil,
  service: nil,
  start_time: nil,
  tags: nil,
  type: nil,
  &block
)
  # Don't allow more span measurements if the
  # trace is already completed. Prevents multiple
  # root spans with parent_span_id = 0.
  return yield(SpanOperation.new(op_name), TraceOperation.new) if finished? || full?

  # Create new span
  span_op = build_span(
    op_name,
    events: events,
    on_error: on_error,
    resource: resource,
    service: service,
    start_time: start_time,
    tags: tags,
    type: type
  )

  # Start span measurement
  span_op.measure { |s| yield(s, self) }
end

#priority_sampled? ⇒ Boolean

Has the priority sampling chosen to keep this span?

Returns:

  • (Boolean) 


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# File 'lib/datadog/tracing/trace_operation.rb', line 130

def priority_sampled?
  !@sampling_priority.nil? && @sampling_priority > 0
end

#reject! ⇒ Object 



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# File 'lib/datadog/tracing/trace_operation.rb', line 140

def reject!
  self.sampled = false
  self.sampling_priority = Sampling::Ext::Priority::USER_REJECT
  set_tag(Tracing::Metadata::Ext::Distributed::TAG_DECISION_MAKER, Tracing::Sampling::Ext::Decision::MANUAL)
end

#resource_override? ⇒ Boolean

Returns true if the resource has been explicitly set

Returns:

  • (Boolean) 


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# File 'lib/datadog/tracing/trace_operation.rb', line 157

def resource_override?
  !@resource.nil?
end

#sampled? ⇒ Boolean

Will this trace be flushed by the tracer transport? This includes cases where the span is kept solely due to priority sampling.

This is not the ultimate Datadog App sampling decision. Downstream systems can decide to reject this trace, especially for cases where priority sampling is set to AUTO_KEEP.

Returns:

  • (Boolean) 


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# File 'lib/datadog/tracing/trace_operation.rb', line 124

def sampled?
  @sampled == true || priority_sampled?
end

#to_digest ⇒ Object

Returns a set of trace headers used for continuing traces. Used for propagation across execution contexts. Data should reflect the active state of the trace.



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# File 'lib/datadog/tracing/trace_operation.rb', line 273

def to_digest
  # Resolve current span ID
  span_id = @active_span && @active_span.id
  span_id ||= @parent_span_id unless finished?

  TraceDigest.new(
    span_id: span_id,
    span_name: (@active_span && @active_span.name),
    span_resource: (@active_span && @active_span.resource),
    span_service: (@active_span && @active_span.service),
    span_type: (@active_span && @active_span.type),
    trace_distributed_tags: distributed_tags,
    trace_hostname: @hostname,
    trace_id: @id,
    trace_name: name,
    trace_origin: @origin,
    trace_process_id: Core::Environment::Identity.pid,
    trace_resource: resource,
    trace_runtime_id: Core::Environment::Identity.id,
    trace_sampling_priority: @sampling_priority,
    trace_service: service,
  ).freeze
end