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

Returns a new instance of TraceOperation.



57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
 
# File 'lib/datadog/tracing/trace_operation.rb', line 57

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,
  remote_parent: false,
  tracer: 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
  @remote_parent = remote_parent

  # 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
  @tracer = tracer

  # 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.



42
43
44
 
# File 'lib/datadog/tracing/trace_operation.rb', line 42

def active_span
  @active_span
end

#active_span_count ⇒ Object (readonly)

Returns the value of attribute active_span_count.



42
43
44
 
# File 'lib/datadog/tracing/trace_operation.rb', line 42

def active_span_count
  @active_span_count
end

#agent_sample_rate ⇒ Object

Returns the value of attribute agent_sample_rate.



32
33
34
 
# 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.



32
33
34
 
# File 'lib/datadog/tracing/trace_operation.rb', line 32

def hostname
  @hostname
end

#id ⇒ Object (readonly)

Returns the value of attribute id.



42
43
44
 
# File 'lib/datadog/tracing/trace_operation.rb', line 42

def id
  @id
end

#max_length ⇒ Object (readonly)

Returns the value of attribute max_length.



42
43
44
 
# File 'lib/datadog/tracing/trace_operation.rb', line 42

def max_length
  @max_length
end

#name ⇒ Object 



159
160
161
 
# File 'lib/datadog/tracing/trace_operation.rb', line 159

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

#origin ⇒ Object

Returns the value of attribute origin.



32
33
34
 
# 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.



42
43
44
 
# File 'lib/datadog/tracing/trace_operation.rb', line 42

def parent_span_id
  @parent_span_id
end

#rate_limiter_rate ⇒ Object

Returns the value of attribute rate_limiter_rate.



32
33
34
 
# File 'lib/datadog/tracing/trace_operation.rb', line 32

def rate_limiter_rate
  @rate_limiter_rate
end

#remote_parent ⇒ Object

Returns the value of attribute remote_parent.



32
33
34
 
# File 'lib/datadog/tracing/trace_operation.rb', line 32

def remote_parent
  @remote_parent
end

#resource ⇒ Object 



163
164
165
 
# File 'lib/datadog/tracing/trace_operation.rb', line 163

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

#rule_sample_rate ⇒ Object

Returns the value of attribute rule_sample_rate.



32
33
34
 
# 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.



32
33
34
 
# 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.



51
52
53
 
# File 'lib/datadog/tracing/trace_operation.rb', line 51

def sampled=(value)
  @sampled = value
end

#sampling_priority ⇒ Object

Returns the value of attribute sampling_priority.



32
33
34
 
# File 'lib/datadog/tracing/trace_operation.rb', line 32

def sampling_priority
  @sampling_priority
end

#service ⇒ Object 



191
192
193
 
# File 'lib/datadog/tracing/trace_operation.rb', line 191

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

#trace_state ⇒ Object (readonly)

Returns the value of attribute trace_state.



42
43
44
 
# File 'lib/datadog/tracing/trace_operation.rb', line 42

def trace_state
  @trace_state
end

#trace_state_unknown_fields ⇒ Object (readonly)

Returns the value of attribute trace_state_unknown_fields.



42
43
44
 
# File 'lib/datadog/tracing/trace_operation.rb', line 42

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, id: nil) ⇒ Object 



229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
 
# File 'lib/datadog/tracing/trace_operation.rb', line 229

def build_span(
  op_name,
  events: nil,
  on_error: nil,
  resource: nil,
  service: nil,
  start_time: nil,
  tags: nil,
  type: nil,
  id: 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,
      id: id
    )
  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) 


126
127
128
 
# File 'lib/datadog/tracing/trace_operation.rb', line 126

def finished?
  @finished == true
end

#finished_span_count ⇒ Object 



122
123
124
 
# File 'lib/datadog/tracing/trace_operation.rb', line 122

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:



291
292
293
294
295
296
297
298
299
300
301
302
 
# File 'lib/datadog/tracing/trace_operation.rb', line 291

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.



351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
 
# File 'lib/datadog/tracing/trace_operation.rb', line 351

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,
    remote_parent: @remote_parent
  )
end

#full? ⇒ Boolean

Returns:

  • (Boolean) 


118
119
120
 
# File 'lib/datadog/tracing/trace_operation.rb', line 118

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

#get_metric(key) ⇒ Object 



172
173
174
 
# File 'lib/datadog/tracing/trace_operation.rb', line 172

def get_metric(key)
  super || (root_span && root_span.get_metric(key))
end

#get_tag(key) ⇒ Object

When retrieving tags or metrics we need to include root span tags for sampling purposes



168
169
170
 
# File 'lib/datadog/tracing/trace_operation.rb', line 168

def get_tag(key)
  super || (root_span && root_span.get_tag(key))
end

#keep! ⇒ Object 



148
149
150
151
152
 
# File 'lib/datadog/tracing/trace_operation.rb', line 148

def keep!
  self.sampling_priority = Sampling::Ext::Priority::USER_KEEP
  set_tag(Tracing::Metadata::Ext::Distributed::TAG_DECISION_MAKER, Tracing::Sampling::Ext::Decision::MANUAL)
  self.sampled = true # Just in case the in-app sampler had decided to drop this span, we revert that decision.
end

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



195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
 
# File 'lib/datadog/tracing/trace_operation.rb', line 195

def measure(
  op_name,
  events: nil,
  on_error: nil,
  resource: nil,
  service: nil,
  start_time: nil,
  tags: nil,
  type: nil,
  id: 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,
    id: id
  )

  # 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) 


144
145
146
 
# File 'lib/datadog/tracing/trace_operation.rb', line 144

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

#reject! ⇒ Object 



154
155
156
157
 
# File 'lib/datadog/tracing/trace_operation.rb', line 154

def reject!
  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) 


187
188
189
 
# File 'lib/datadog/tracing/trace_operation.rb', line 187

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) 


138
139
140
 
# File 'lib/datadog/tracing/trace_operation.rb', line 138

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

#tags ⇒ Object 



176
177
178
179
180
181
182
 
# File 'lib/datadog/tracing/trace_operation.rb', line 176

def tags
  all_tags = {}
  all_tags.merge!(root_span&.tags || {}) if root_span
  all_tags.merge!(super)

  all_tags
end

#to_correlation ⇒ Object 



338
339
340
341
342
343
344
345
346
347
 
# File 'lib/datadog/tracing/trace_operation.rb', line 338

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

  Correlation::Identifier.new(
    trace_id: @id,
    span_id: span_id
  )
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. DEV-3.0: Sampling is a side effect of generating the digest. We should move the sample call to inject and right before moving to new contexts(threads, forking etc.)



309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
 
# File 'lib/datadog/tracing/trace_operation.rb', line 309

def to_digest
  # Resolve current span ID
  span_id = @active_span && @active_span.id
  span_id ||= @parent_span_id unless finished?
  # sample the trace_operation with the tracer
  @tracer&.sample_trace(self) unless sampling_priority

  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,
    span_remote: (@remote_parent && @active_span.nil?),
  ).freeze
end