Class: Ductwork::BranchClaim

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

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(pipeline_klass) ⇒ BranchClaim

Returns a new instance of BranchClaim.



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# File 'lib/ductwork/branch_claim.rb', line 7

def initialize(pipeline_klass)
  @pipeline_klass = pipeline_klass
  @claimed_for_advancing_at = nil
end

Instance Attribute Details

#advancement ⇒ Object (readonly)

Returns the value of attribute advancement.



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# File 'lib/ductwork/branch_claim.rb', line 5

def advancement
  @advancement
end

#token ⇒ Object (readonly)

Returns the value of attribute token.



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# File 'lib/ductwork/branch_claim.rb', line 5

def token
  @token
end

#transition ⇒ Object (readonly)

Returns the value of attribute transition.



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# File 'lib/ductwork/branch_claim.rb', line 5

def transition
  @transition
end

Instance Method Details

#latest ⇒ Object 



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# File 'lib/ductwork/branch_claim.rb', line 12

def latest
  # NOTE: an advancement must attach to a live process record so the reaper
  # can find and recover it if this process dies. `Process.current` is only
  # nil when our record was reaped for a stale heartbeat (e.g. host suspend)
  # and the runner has not re-adopted it yet — i.e. the system has already
  # declared this process dead. Claiming as a presumed-dead zombie would
  # create an advancement with a nil `process_id` that no reaper sweep can
  # reach, orphaning the branch. Skip this cycle instead; the runner
  # re-adopts within its heartbeat interval.
  process = Ductwork::Process.current

  return log_no_process if process.nil?

  id = find_candidate_branch_id

  return log_no_branches if id.blank?

  rows_updated = claim_and_setup_records(id, process)

  if rows_updated == 1
    Ductwork::Branch.find(id)
  else
    log_race_condition(id)
  end
rescue ActiveRecord::InvalidForeignKey => e
  # NOTE: our own `process` record was reaped (heartbeat-stale, destroyed)
  # between the nil-check above and `transition.advancements.create!`
  # inside `claim_and_setup_records`. The insert's FK check blocks on the
  # reaper's row lock and then fails once the parent is gone, rolling back
  # the whole claim transaction (branch + transition + advancement) --
  # nothing is left half-committed. Treat it like any other lost claim
  # race instead of letting it propagate and kill the advancer thread.
  log_process_reaped_mid_claim(id, e)
end