Module: WithAdvisoryLock::CoreAdvisory

Extended by:
ActiveSupport::Concern
Defined in:
lib/with_advisory_lock/core_advisory.rb

Constant Summary collapse

LOCK_PREFIX_ENV = 
'WITH_ADVISORY_LOCK_PREFIX'

Instance Method Summary collapse

Instance Method Details

#advisory_lock_stack ⇒ Object

Thread-local lock stack management



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# File 'lib/with_advisory_lock/core_advisory.rb', line 12

def advisory_lock_stack
  Thread.current[:with_advisory_lock_stack] ||= []
end

#with_advisory_lock_if_needed(lock_name, options = {}, &block) ⇒ Object 



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# File 'lib/with_advisory_lock/core_advisory.rb', line 16

def with_advisory_lock_if_needed(lock_name, options = {}, &block)
  options = { timeout_seconds: options } unless options.respond_to?(:fetch)
  options.assert_valid_keys :timeout_seconds, :shared, :transaction, :disable_query_cache

  # Validate transaction-level locks are used within a transaction
  if options.fetch(:transaction, false) && !transaction_open?
    raise ArgumentError, 'transaction-level advisory locks require an active transaction'
  end

  lock_str = "#{ENV.fetch(LOCK_PREFIX_ENV, nil)}#{lock_name}"
  lock_stack_item = LockStackItem.new(lock_str, options.fetch(:shared, false))

  if advisory_lock_stack.include?(lock_stack_item)
    # Already have this exact lock (same name and type), just yield
    return Result.new(lock_was_acquired: true, result: yield)
  end

  # Check if we have a lock with the same name but different type (for upgrade/downgrade)
  same_name_different_type = advisory_lock_stack.any? do |item|
    item.name == lock_str && item.shared != options.fetch(:shared, false)
  end
  if same_name_different_type && options.fetch(:transaction, false)
    # PostgreSQL doesn't support upgrading/downgrading transaction-level locks
    return Result.new(lock_was_acquired: false)
  end

  disable_query_cache = options.fetch(:disable_query_cache, false)

  if disable_query_cache
    uncached do
      advisory_lock_and_yield(lock_name, lock_str, lock_stack_item, options, &block)
    end
  else
    advisory_lock_and_yield(lock_name, lock_str, lock_stack_item, options, &block)
  end
end