Class: Datadog::RateSampler
Overview
RateSampler is based on a sample rate.
Constant Summary collapse
- KNUTH_FACTOR =
1111111111111111111
- SAMPLE_RATE_METRIC_KEY =
'_sample_rate'.freeze
Instance Method Summary collapse
-
#initialize(sample_rate = 1.0) ⇒ RateSampler
constructor
Initialize a RateSampler.
- #sample!(span) ⇒ Object
- #sample?(span) ⇒ Boolean
- #sample_rate(*_) ⇒ Object
- #sample_rate=(sample_rate) ⇒ Object
Constructor Details
#initialize(sample_rate = 1.0) ⇒ RateSampler
Initialize a RateSampler. This sampler keeps a random subset of the traces. Its main purpose is to reduce the instrumentation footprint.
-
sample_rate
: the sample rate as a Float between 0.0 and 1.0. 0.0 means that no trace will be sampled; 1.0 means that all traces will be sampled.
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# File 'lib/ddtrace/sampler.rb', line 49 def initialize(sample_rate = 1.0) unless sample_rate > 0.0 && sample_rate <= 1.0 Datadog.logger.error('sample rate is not between 0 and 1, disabling the sampler') sample_rate = 1.0 end self.sample_rate = sample_rate end |
Instance Method Details
#sample!(span) ⇒ Object
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# File 'lib/ddtrace/sampler.rb', line 71 def sample!(span) (span.sampled = sample?(span)).tap do |sampled| span.set_metric(SAMPLE_RATE_METRIC_KEY, @sample_rate) if sampled end end |
#sample?(span) ⇒ Boolean
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# File 'lib/ddtrace/sampler.rb', line 67 def sample?(span) ((span.trace_id * KNUTH_FACTOR) % Datadog::Span::MAX_ID) <= @sampling_id_threshold end |
#sample_rate(*_) ⇒ Object
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# File 'lib/ddtrace/sampler.rb', line 58 def sample_rate(*_) @sample_rate end |