Module: Datadog::Profiling::SequenceTracker

Extended by:
Core::Utils::Forking
Defined in:
lib/datadog/profiling/sequence_tracker.rb

Overview

Used to generate the ‘profile_seq` tag, which effectively counts how many profiles we’ve attempted to report from a given runtime-id.

Note that the above implies a few things:

  1. The sequence number only gets incremented when we decide to report a profile and create a ‘Flush` for it

  2. The ‘SequenceTracker` must live across profiler reconfigurations and resets, since no matter how many profiler instances get created due to reconfiguration, the runtime-id is still the same, so the sequence number should be kept and not restarted from 0

  3. The ‘SequenceTracker` must be reset after a fork, since the runtime-id will change, and we want to start counting from 0 again

This is why this module is implemented as a singleton that we reuse, not as an instance that we recreate.

Note that this module is not thread-safe, so it’s up to the callers to make sure it’s only used by a single thread at a time (which is what the ‘Profiling::Exporter`) is doing.

Class Method Summary collapse

Methods included from Core::Utils::Forking

after_fork!, extended, fork_pid, forked?, included, update_fork_pid!

Class Method Details

.get_next ⇒ Object 



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# File 'lib/datadog/profiling/sequence_tracker.rb', line 27

def get_next
  reset! unless defined?(@sequence_number)
  after_fork! { reset! }

  next_seq = @sequence_number
  @sequence_number += 1
  next_seq
end