Class: Ditliti::TraceContext

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

Overview

A W3C trace-context (https://www.w3.org/TR/trace-context/) carried across service boundaries via the traceparent header, so a trace started in one process is continued - not restarted - in the next.

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(trace_id, span_id, sampled = true) ⇒ TraceContext

Returns a new instance of TraceContext.



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# File 'lib/ditliti.rb', line 43

def initialize(trace_id, span_id, sampled = true)
  @trace_id = trace_id
  @span_id = span_id
  @sampled = sampled
end

Instance Attribute Details

#sampled ⇒ Object (readonly)

Returns the value of attribute sampled.



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# File 'lib/ditliti.rb', line 13

def sampled
  @sampled
end

#span_id ⇒ Object (readonly)

Returns the value of attribute span_id.



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# File 'lib/ditliti.rb', line 13

def span_id
  @span_id
end

#trace_id ⇒ Object (readonly)

Returns the value of attribute trace_id.



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# File 'lib/ditliti.rb', line 13

def trace_id
  @trace_id
end

Class Method Details

.from_traceparent(header) ⇒ Object 



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# File 'lib/ditliti.rb', line 27

def self.from_traceparent(header)
  return nil if header.nil? || header.strip.empty?

  parts = header.strip.split("-")
  return nil unless parts.length == 4

  _version, trace_id, span_id, flags = parts
  return nil unless trace_id =~ /\A[0-9a-f]{32}\z/ && trace_id != "0" * 32
  return nil unless span_id =~ /\A[0-9a-f]{16}\z/ && span_id != "0" * 16

  flags_value = Integer(flags, 16) rescue nil
  return nil if flags_value.nil?

  new(trace_id, span_id, (flags_value & 1) == 1)
end

.generate_span_id ⇒ Object 



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# File 'lib/ditliti.rb', line 19

def self.generate_span_id
  SecureRandom.hex(8)
end

.generate_trace_id ⇒ Object 



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# File 'lib/ditliti.rb', line 15

def self.generate_trace_id
  SecureRandom.hex(16)
end

.start ⇒ Object 



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# File 'lib/ditliti.rb', line 23

def self.start
  new(generate_trace_id, generate_span_id, true)
end

Instance Method Details

#child ⇒ Object 



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# File 'lib/ditliti.rb', line 49

def child
  self.class.new(trace_id, self.class.generate_span_id, sampled)
end

#to_traceparent ⇒ Object 



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# File 'lib/ditliti.rb', line 53

def to_traceparent
  "00-#{trace_id}-#{span_id}-#{sampled ? "01" : "00"}"
end