Module: RaceGuard::Distributed::Runner

Defined in:
lib/race_guard/distributed/runner.rb

Overview

Orchestrates claim / yield / release and reporting. rubocop:disable Metrics/ModuleLength, Metrics/ClassLength – Epic 10 runner rubocop:disable Layout/LineLength, Metrics/ParameterLists, Metrics/MethodLength – Epic 10 runner rubocop:disable Metrics/AbcSize, Metrics/CyclomaticComplexity, Metrics/PerceivedComplexity – Epic 10 runner

Constant Summary collapse

HELD_STACK_KEY = 
:__race_guard_distributed_held_stack__

Class Method Summary collapse

Class Method Details

.base_context(event:, lock_name:, lock_key:, resource_digest:, token:, ttl:, caller_line:, store_class:) ⇒ Object 



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# File 'lib/race_guard/distributed/runner.rb', line 284

def base_context(event:, lock_name:, lock_key:, resource_digest:, token:, ttl:, caller_line:, store_class:)
  {
    'event' => event,
    'lock_name' => lock_name,
    'lock_key' => lock_key,
    'resource_hash' => resource_digest,
    'owner_token_hash' => token_hash(token),
    'ttl' => ttl,
    'caller' => caller_line,
    'store_class' => store_class
  }.compact
end

.effective_skip_behavior(on_skip, cfg) ⇒ Object 



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# File 'lib/race_guard/distributed/runner.rb', line 310

def effective_skip_behavior(on_skip, cfg)
  (on_skip.nil? ? cfg.distributed_skip_behavior : on_skip).to_sym
end

.effective_store(cfg) ⇒ Object 



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# File 'lib/race_guard/distributed/runner.rb', line 297

def effective_store(cfg)
  cfg.distributed_lock_store ||
    (cfg.distributed_redis_client && RedisLockStore.new(cfg.distributed_redis_client))
end

.emit_claimed(lock_name, lock_key, resource_digest, token, ttl, caller_line, store_class) ⇒ Object 



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# File 'lib/race_guard/distributed/runner.rb', line 168

def emit_claimed(lock_name, lock_key, resource_digest, token, ttl, caller_line, store_class)
  emit_lifecycle(
    event: 'claimed',
    lock_name: lock_name,
    lock_key: lock_key,
    resource_digest: resource_digest,
    token: token,
    ttl: ttl,
    caller_line: caller_line,
    store_class: store_class
  )
end

.emit_error(event:, lock_name:, lock_key:, resource_digest:, token:, ttl:, caller_line:, store_class:, error:, extra: {}) ⇒ Object 



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# File 'lib/race_guard/distributed/runner.rb', line 252

def emit_error(event:, lock_name:, lock_key:, resource_digest:, token:, ttl:, caller_line:, store_class:,
               error:, extra: {})
  return unless RaceGuard.configuration.active?

  ctx = base_context(
    event: event,
    lock_name: lock_name,
    lock_key: lock_key,
    resource_digest: resource_digest,
    token: token,
    ttl: ttl,
    caller_line: caller_line,
    store_class: store_class
  )
  ctx.merge!(stringify_keys(extra))
  ctx['error_class'] = error.class.name if error
  ctx['error_message'] = error.message.to_s[0, 500] if error
  sev = RaceGuard.configuration.severity_for(:distributed_guard)
  RaceGuard.report(
    detector: 'distributed_guard',
    message: "distributed_guard:#{event}",
    severity: sev,
    context: ctx
  )
end

.emit_lifecycle(event:, lock_name:, lock_key:, resource_digest:, token:, ttl:, caller_line:, store_class: nil, extra: {}, severity: :info) ⇒ Object 



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# File 'lib/race_guard/distributed/runner.rb', line 229

def emit_lifecycle(event:, lock_name:, lock_key:, resource_digest:, token:, ttl:, caller_line:,
                   store_class: nil, extra: {}, severity: :info)
  return unless RaceGuard.configuration.active?

  ctx = base_context(
    event: event,
    lock_name: lock_name,
    lock_key: lock_key,
    resource_digest: resource_digest,
    token: token,
    ttl: ttl,
    caller_line: caller_line,
    store_class: store_class
  )
  ctx.merge!(stringify_keys(extra))
  RaceGuard.report(
    detector: 'distributed_guard',
    message: "distributed_guard:#{event}",
    severity: severity,
    context: ctx
  )
end

.emit_skipped_lost_race(lock_name, lock_key, resource_digest, token, ttl, caller_line, store_class, on_skip, cfg) ⇒ Object 



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# File 'lib/race_guard/distributed/runner.rb', line 152

def emit_skipped_lost_race(lock_name, lock_key, resource_digest, token, ttl, caller_line, store_class,
                           on_skip, cfg)
  skip_behavior = effective_skip_behavior(on_skip, cfg)
  emit_lifecycle(
    event: 'skipped',
    lock_name: lock_name,
    lock_key: lock_key,
    resource_digest: resource_digest,
    token: token,
    ttl: ttl,
    caller_line: caller_line,
    store_class: store_class,
    extra: { 'skip_reason' => 'lost_race', 'skip_behavior' => skip_behavior.to_s }
  )
end

.emit_skipped_reentrant(lock_name, lock_key, resource_digest, ttl, caller_line, on_skip, cfg) ⇒ Object 



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# File 'lib/race_guard/distributed/runner.rb', line 137

def emit_skipped_reentrant(lock_name, lock_key, resource_digest, ttl, caller_line, on_skip, cfg)
  skip_behavior = effective_skip_behavior(on_skip, cfg)
  emit_lifecycle(
    event: 'skipped',
    lock_name: lock_name,
    lock_key: lock_key,
    resource_digest: resource_digest,
    token: nil,
    ttl: ttl,
    caller_line: caller_line,
    store_class: nil,
    extra: { 'skip_reason' => 'reentrant', 'skip_behavior' => skip_behavior.to_s }
  )
end

.finalize_release(store, lock_key, token, lock_name, resource_digest, ttl, caller_line, store_class) ⇒ Object 



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# File 'lib/race_guard/distributed/runner.rb', line 181

def finalize_release(store, lock_key, token, lock_name, resource_digest, ttl, caller_line, store_class)
  release_error = nil
  released =
    begin
      store.release(key: lock_key, token: token)
    rescue StandardError => e
      release_error = e
      false
    end
  if release_error
    emit_error(
      event: 'release_failed',
      lock_name: lock_name,
      lock_key: lock_key,
      resource_digest: resource_digest,
      token: token,
      ttl: ttl,
      caller_line: caller_line,
      store_class: store_class,
      error: release_error
    )
  elsif released
    emit_lifecycle(
      event: 'released',
      lock_name: lock_name,
      lock_key: lock_key,
      resource_digest: resource_digest,
      token: token,
      ttl: ttl,
      caller_line: caller_line,
      store_class: store_class
    )
  else
    emit_lifecycle(
      event: 'release_failed',
      lock_name: lock_name,
      lock_key: lock_key,
      resource_digest: resource_digest,
      token: token,
      ttl: ttl,
      caller_line: caller_line,
      store_class: store_class,
      extra: { 'note' => 'compare-and-delete did not remove key (expired or stolen)' },
      severity: :warn
    )
  end
end

.handle_skip(_block, on_skip, default_behavior) ⇒ Object 



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# File 'lib/race_guard/distributed/runner.rb', line 314

def handle_skip(_block, on_skip, default_behavior)
  behavior = (on_skip.nil? ? default_behavior : on_skip).to_sym
  case behavior
  when :nil
    nil
  when :sentinel
    SKIPPED
  when :raise
    raise LockNotAcquiredError, 'distributed lock not acquired'
  else
    raise ArgumentError,
          "invalid on_skip / distributed_skip_behavior: #{behavior.inspect} " \
          '(expected :nil, :sentinel, or :raise)'
  end
end

.run(name:, ttl:, resource:, on_skip:, &block) ⇒ Object

Raises:

  • (ArgumentError) 


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# File 'lib/race_guard/distributed/runner.rb', line 59

def run(name:, ttl:, resource:, on_skip:, &block)
  raise ArgumentError, 'RaceGuard.distributed_once requires a block' unless block

  cfg = RaceGuard.configuration
  lock_name = name.to_s
  caller_line = safe_caller

  return yield_simple(block, nil) if !cfg.enabled?(:distributed_guard) || !cfg.active?

  unless ttl.is_a?(Integer) && ttl.positive?
    raise ArgumentError, 'ttl must be a positive Integer (seconds)'
  end

  prefix = cfg.distributed_key_prefix
  lock_key = KeyBuilder.build(name: lock_name, resource: resource, prefix: prefix)
  resource_digest = KeyBuilder.resource_digest(resource)

  stack = Thread.current[HELD_STACK_KEY] ||= []
  if cfg.distributed_reentrancy == :skip && stack.include?(lock_key)
    emit_skipped_reentrant(
      lock_name, lock_key, resource_digest, ttl, caller_line, on_skip, cfg
    )
    return handle_skip(block, on_skip, cfg.distributed_skip_behavior)
  end

  store = effective_store(cfg)
  if store.nil?
    return run_misconfigured_store(cfg, block, on_skip, lock_name, lock_key, resource_digest, ttl,
                                   caller_line)
  end

  store_class = store.class.name
  token = SecureRandom.hex(16)
  res, payload = try_claim(store, lock_key, token, ttl.to_i)
  if res == :err
    return run_store_error(
      cfg, block, on_skip, lock_name, lock_key, resource_digest, ttl, caller_line, store_class, payload
    )
  end

  claimed = payload
  unless claimed
    emit_skipped_lost_race(
      lock_name, lock_key, resource_digest, token, ttl, caller_line, store_class, on_skip, cfg
    )
    return handle_skip(block, on_skip, cfg.distributed_skip_behavior)
  end

  emit_claimed(lock_name, lock_key, resource_digest, token, ttl, caller_line, store_class)
  stack << lock_key
  control = LockControl.new(
    {
      store: store,
      lock_key: lock_key,
      token: token,
      ttl: ttl.to_i,
      lock_name: lock_name,
      resource_digest: resource_digest,
      caller_line: caller_line,
      store_class: store_class
    }
  )
  begin
    yield_simple(block, control)
  ensure
    stack.pop if stack.last == lock_key
    finalize_release(
      store, lock_key, token, lock_name, resource_digest, ttl, caller_line, store_class
    )
  end
end

.run_misconfigured_store(cfg, block, on_skip, lock_name, lock_key, resource_digest, ttl, caller_line) ⇒ Object 



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# File 'lib/race_guard/distributed/runner.rb', line 330

def run_misconfigured_store(cfg, block, on_skip, lock_name, lock_key, resource_digest, ttl, caller_line)
  return yield_simple(block, nil) if cfg.distributed_degrade_silently

  emit_error(
    event: 'configuration_error',
    lock_name: lock_name,
    lock_key: lock_key,
    resource_digest: resource_digest,
    token: nil,
    ttl: ttl,
    caller_line: caller_line,
    store_class: nil,
    error: nil,
    extra: {
      'reason' => 'missing_lock_store',
      'hint' => 'set distributed_lock_store or distributed_redis_client'
    }
  )
  handle_skip(block, on_skip, cfg.distributed_skip_behavior)
end

.run_store_error(cfg, block, on_skip, lock_name, lock_key, resource_digest, ttl, caller_line, store_class, error) ⇒ Object 



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# File 'lib/race_guard/distributed/runner.rb', line 351

def run_store_error(cfg, block, on_skip, lock_name, lock_key, resource_digest, ttl, caller_line,
                    store_class, error)
  return yield_simple(block, nil) if cfg.distributed_degrade_silently

  emit_error(
    event: 'redis_error',
    lock_name: lock_name,
    lock_key: lock_key,
    resource_digest: resource_digest,
    token: nil,
    ttl: ttl,
    caller_line: caller_line,
    store_class: store_class,
    error: error
  )
  handle_skip(block, on_skip, cfg.distributed_skip_behavior)
end

.safe_caller ⇒ Object 



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# File 'lib/race_guard/distributed/runner.rb', line 369

def safe_caller
  loc = caller_locations(2, 1)&.first
  loc ? "#{loc.path}:#{loc.lineno}:in `#{loc.label}'" : ''
end

.stringify_keys(hash) ⇒ Object 



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# File 'lib/race_guard/distributed/runner.rb', line 374

def stringify_keys(hash)
  hash.to_h { |k, v| [k.to_s, v] }
end

.token_hash(token) ⇒ Object 



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# File 'lib/race_guard/distributed/runner.rb', line 278

def token_hash(token)
  return nil unless token

  Digest::SHA256.hexdigest(token.to_s)[0, 32]
end

.try_claim(store, lock_key, token, ttl) ⇒ Object 



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# File 'lib/race_guard/distributed/runner.rb', line 131

def try_claim(store, lock_key, token, ttl)
  [:ok, store.claim(key: lock_key, token: token, ttl: ttl)]
rescue StandardError => e
  [:err, e]
end

.yield_simple(block, control) ⇒ Object 



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# File 'lib/race_guard/distributed/runner.rb', line 302

def yield_simple(block, control)
  if block.arity.zero?
    block.call
  else
    block.call(control)
  end
end