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, #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, profiling_enabled: nil, tags: nil, metrics: nil, trace_state: nil, trace_state_unknown_fields: nil) ⇒ TraceOperation

Returns a new instance of TraceOperation.



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# File 'lib/datadog/tracing/trace_operation.rb', line 53

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,
  profiling_enabled: nil,
  tags: nil,
  metrics: nil,
  trace_state: nil,
  trace_state_unknown_fields: nil
)
  # Attributes
  @id = id || Tracing::Utils::TraceId.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
  @profiling_enabled = profiling_enabled
  @trace_state = trace_state
  @trace_state_unknown_fields = trace_state_unknown_fields

  # 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 38

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 38

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 29

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 29

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 38

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 38

def max_length
  @max_length
end

#name ⇒ Object 



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# File 'lib/datadog/tracing/trace_operation.rb', line 151

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 29

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 38

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 29

def rate_limiter_rate
  @rate_limiter_rate
end

#resource ⇒ Object 



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# File 'lib/datadog/tracing/trace_operation.rb', line 155

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 29

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 29

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 47

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 29

def sampling_priority
  @sampling_priority
end

#service ⇒ Object 



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# File 'lib/datadog/tracing/trace_operation.rb', line 166

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

#trace_state ⇒ Object (readonly)

Returns the value of attribute trace_state.



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# File 'lib/datadog/tracing/trace_operation.rb', line 38

def trace_state
  @trace_state
end

#trace_state_unknown_fields ⇒ Object (readonly)

Returns the value of attribute trace_state_unknown_fields.



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# File 'lib/datadog/tracing/trace_operation.rb', line 38

def trace_state_unknown_fields
  @trace_state_unknown_fields
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 202

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 117

def finished?
  @finished == true
end

#finished_span_count ⇒ Object 



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# File 'lib/datadog/tracing/trace_operation.rb', line 113

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 262

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 306

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),
    trace_state: (@trace_state && @trace_state.dup),
    trace_state_unknown_fields: (@trace_state_unknown_fields && @trace_state_unknown_fields.dup),
    tags: meta.dup,
    metrics: metrics.dup
  )
end

#full? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/datadog/tracing/trace_operation.rb', line 109

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 139

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 170

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 135

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

#reject! ⇒ Object 



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# File 'lib/datadog/tracing/trace_operation.rb', line 145

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 162

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 129

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 278

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,
    trace_state: @trace_state,
    trace_state_unknown_fields: @trace_state_unknown_fields,
  ).freeze
end