Module: Concurrent

Defined in:
lib/concurrent-ruby/concurrent.rb,
lib/concurrent-ruby/concurrent/map.rb,
lib/concurrent-ruby/concurrent/set.rb,
lib/concurrent-ruby/concurrent/atom.rb,
lib/concurrent-ruby/concurrent/hash.rb,
lib/concurrent-ruby/concurrent/ivar.rb,
lib/concurrent-ruby/concurrent/mvar.rb,
lib/concurrent-ruby/concurrent/tvar.rb,
lib/concurrent-ruby/concurrent/agent.rb,
lib/concurrent-ruby/concurrent/array.rb,
lib/concurrent-ruby/concurrent/async.rb,
lib/concurrent-ruby/concurrent/delay.rb,
lib/concurrent-ruby/concurrent/maybe.rb,
lib/concurrent-ruby/concurrent/tuple.rb,
lib/concurrent-ruby/concurrent/errors.rb,
lib/concurrent-ruby/concurrent/future.rb,
lib/concurrent-ruby/concurrent/options.rb,
lib/concurrent-ruby/concurrent/promise.rb,
lib/concurrent-ruby/concurrent/version.rb,
lib/concurrent-ruby/concurrent/dataflow.rb,
lib/concurrent-ruby/concurrent/promises.rb,
lib/concurrent-ruby/concurrent/constants.rb,
lib/concurrent-ruby/concurrent/exchanger.rb,
lib/concurrent-ruby/concurrent/re_include.rb,
lib/concurrent-ruby/concurrent/timer_task.rb,
lib/concurrent-ruby/concurrent/atomic/event.rb,
lib/concurrent-ruby/concurrent/configuration.rb,
lib/concurrent-ruby/concurrent/mutable_struct.rb,
lib/concurrent-ruby/concurrent/scheduled_task.rb,
lib/concurrent-ruby/concurrent/utility/engine.rb,
lib/concurrent-ruby/concurrent/concern/logging.rb,
lib/concurrent-ruby/concurrent/settable_struct.rb,
lib/concurrent-ruby/concurrent/synchronization.rb,
lib/concurrent-ruby/concurrent/atomic/semaphore.rb,
lib/concurrent-ruby/concurrent/immutable_struct.rb,
lib/concurrent-ruby/concurrent/thread_safe/util.rb,
lib/concurrent-ruby/concurrent/concern/obligation.rb,
lib/concurrent-ruby/concurrent/concern/observable.rb,
lib/concurrent-ruby/concurrent/executor/timer_set.rb,
lib/concurrent-ruby/concurrent/concern/deprecation.rb,
lib/concurrent-ruby/concurrent/atomic/atomic_fixnum.rb,
lib/concurrent-ruby/concurrent/synchronization/lock.rb,
lib/concurrent-ruby/concurrent/atomic/atomic_boolean.rb,
lib/concurrent-ruby/concurrent/atomic/cyclic_barrier.rb,
lib/concurrent-ruby/concurrent/atomic/mutex_semaphore.rb,
lib/concurrent-ruby/concurrent/atomic/read_write_lock.rb,
lib/concurrent-ruby/concurrent/synchronization/object.rb,
lib/concurrent-ruby/concurrent/thread_safe/util/adder.rb,
lib/concurrent-ruby/concurrent/utility/monotonic_time.rb,
lib/concurrent-ruby/concurrent/utility/native_integer.rb,
lib/concurrent-ruby/concurrent/atomic/atomic_reference.rb,
lib/concurrent-ruby/concurrent/atomic/count_down_latch.rb,
lib/concurrent-ruby/concurrent/atomic/thread_local_var.rb,
lib/concurrent-ruby/concurrent/concern/dereferenceable.rb,
lib/concurrent-ruby/concurrent/synchronization/volatile.rb,
lib/concurrent-ruby/concurrent/executor/executor_service.rb,
lib/concurrent-ruby/concurrent/synchronization/condition.rb,
lib/concurrent-ruby/concurrent/thread_safe/util/volatile.rb,
lib/concurrent-ruby/concurrent/utility/processor_counter.rb,
lib/concurrent-ruby/concurrent/atomic/mutex_atomic_fixnum.rb,
lib/concurrent-ruby/concurrent/collection/lock_free_stack.rb,
lib/concurrent-ruby/concurrent/executor/fixed_thread_pool.rb,
lib/concurrent-ruby/concurrent/synchronization/mri_object.rb,
lib/concurrent-ruby/concurrent/synchronization/rbx_object.rb,
lib/concurrent-ruby/concurrent/thread_safe/util/striped64.rb,
lib/concurrent-ruby/concurrent/atomic/mutex_atomic_boolean.rb,
lib/concurrent-ruby/concurrent/executor/cached_thread_pool.rb,
lib/concurrent-ruby/concurrent/executor/immediate_executor.rb,
lib/concurrent-ruby/concurrent/executor/safe_task_executor.rb,
lib/concurrent-ruby/concurrent/atomic/java_count_down_latch.rb,
lib/concurrent-ruby/concurrent/atomic/java_thread_local_var.rb,
lib/concurrent-ruby/concurrent/atomic/ruby_thread_local_var.rb,
lib/concurrent-ruby/concurrent/synchronization/jruby_object.rb,
lib/concurrent-ruby/concurrent/atomic/mutex_count_down_latch.rb,
lib/concurrent-ruby/concurrent/atomic_reference/mutex_atomic.rb,
lib/concurrent-ruby/concurrent/executor/serialized_execution.rb,
lib/concurrent-ruby/concurrent/executor/thread_pool_executor.rb,
lib/concurrent-ruby/concurrent/collection/map/mri_map_backend.rb,
lib/concurrent-ruby/concurrent/executor/java_executor_service.rb,
lib/concurrent-ruby/concurrent/executor/ruby_executor_service.rb,
lib/concurrent-ruby/concurrent/executor/single_thread_executor.rb,
lib/concurrent-ruby/concurrent/synchronization/abstract_object.rb,
lib/concurrent-ruby/concurrent/synchronization/abstract_struct.rb,
lib/concurrent-ruby/concurrent/synchronization/lockable_object.rb,
lib/concurrent-ruby/concurrent/thread_safe/util/cheap_lockable.rb,
lib/concurrent-ruby/concurrent/utility/native_extension_loader.rb,
lib/concurrent-ruby/concurrent/atomic/abstract_thread_local_var.rb,
lib/concurrent-ruby/concurrent/atomic/atomic_markable_reference.rb,
lib/concurrent-ruby/concurrent/atomic/reentrant_read_write_lock.rb,
lib/concurrent-ruby/concurrent/executor/serial_executor_service.rb,
lib/concurrent-ruby/concurrent/executor/simple_executor_service.rb,
lib/concurrent-ruby/concurrent/thread_safe/util/data_structures.rb,
lib/concurrent-ruby/concurrent/thread_safe/util/xor_shift_random.rb,
lib/concurrent-ruby/concurrent/executor/abstract_executor_service.rb,
lib/concurrent-ruby/concurrent/executor/java_thread_pool_executor.rb,
lib/concurrent-ruby/concurrent/executor/ruby_thread_pool_executor.rb,
lib/concurrent-ruby/concurrent/synchronization/truffleruby_object.rb,
lib/concurrent-ruby/concurrent/thread_safe/synchronized_delegator.rb,
lib/concurrent-ruby/concurrent/synchronization/rbx_lockable_object.rb,
lib/concurrent-ruby/concurrent/thread_safe/util/power_of_two_tuple.rb,
lib/concurrent-ruby/concurrent/atomic_reference/numeric_cas_wrapper.rb,
lib/concurrent-ruby/concurrent/executor/indirect_immediate_executor.rb,
lib/concurrent-ruby/concurrent/executor/java_single_thread_executor.rb,
lib/concurrent-ruby/concurrent/executor/ruby_single_thread_executor.rb,
lib/concurrent-ruby/concurrent/collection/copy_on_write_observer_set.rb,
lib/concurrent-ruby/concurrent/synchronization/jruby_lockable_object.rb,
lib/concurrent-ruby/concurrent/synchronization/mutex_lockable_object.rb,
lib/concurrent-ruby/concurrent/collection/copy_on_notify_observer_set.rb,
lib/concurrent-ruby/concurrent/collection/map/truffleruby_map_backend.rb,
lib/concurrent-ruby/concurrent/collection/map/synchronized_map_backend.rb,
lib/concurrent-ruby/concurrent/executor/serialized_execution_delegator.rb,
lib/concurrent-ruby/concurrent/collection/non_concurrent_priority_queue.rb,
lib/concurrent-ruby/concurrent/synchronization/abstract_lockable_object.rb,
lib/concurrent-ruby/concurrent/collection/map/non_concurrent_map_backend.rb,
lib/concurrent-ruby/concurrent/collection/map/atomic_reference_map_backend.rb,
lib/concurrent-ruby/concurrent/collection/java_non_concurrent_priority_queue.rb,
lib/concurrent-ruby/concurrent/collection/ruby_non_concurrent_priority_queue.rb

Overview

Defined Under Namespace

Modules: Async, Concern, ImmutableStruct, MutableStruct, Promises, ReInclude, SettableStruct, Synchronization, Utility Classes: Agent, Array, Atom, AtomicBoolean, AtomicFixnum, AtomicMarkableReference, AtomicReference, CachedThreadPool, ConcurrentUpdateError, CountDownLatch, CyclicBarrier, Delay, Event, Exchanger, FixedThreadPool, Future, Hash, IVar, ImmediateExecutor, IndirectImmediateExecutor, LockFreeStack, MVar, Map, Maybe, MultipleAssignmentError, MultipleErrors, Promise, ReadWriteLock, ReentrantReadWriteLock, SafeTaskExecutor, ScheduledTask, Semaphore, SerializedExecution, SerializedExecutionDelegator, Set, SimpleExecutorService, SingleThreadExecutor, TVar, ThreadLocalVar, ThreadPoolExecutor, TimerSet, TimerTask, Transaction, Tuple

Constant Summary collapse

Error = 
Class.new(StandardError)
ConfigurationError =

Raised when errors occur during configuration.

Class.new(Error)
CancelledOperationError =

Raised when an asynchronous operation is cancelled before execution.

Class.new(Error)
LifecycleError =

Raised when a lifecycle method (such as ‘stop`) is called in an improper sequence or when the object is in an inappropriate state.

Class.new(Error)
ImmutabilityError =

Raised when an attempt is made to violate an immutability guarantee.

Class.new(Error)
IllegalOperationError =

Raised when an operation is attempted which is not legal given the receiver’s current state

Class.new(Error)
InitializationError =

Raised when an object’s methods are called when it has not been properly initialized.

Class.new(Error)
MaxRestartFrequencyError =

Raised when an object with a start/stop lifecycle has been started an excessive number of times. Often used in conjunction with a restart policy or strategy.

Class.new(Error)
RejectedExecutionError =

Raised by an ‘Executor` when it is unable to process a given task, possibly because of a reject policy or other internal error.

Class.new(Error)
ResourceLimitError =

Raised when any finite resource, such as a lock counter, exceeds its maximum limit/threshold.

Class.new(Error)
TimeoutError =

Raised when an operation times out.

Class.new(Error)
PromiseExecutionError = 
Class.new(StandardError)
VERSION = 
'1.1.13'
NULL_LOGGER =

Suppresses all output when used for logging.

lambda { |level, progname, message = nil, &block| }

Class Method Summary collapse

Instance Method Summary collapse

Class Method Details

.abort_transaction ⇒ Object

Abort a currently running transaction - see ‘Concurrent::atomically`.

Raises:



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# File 'lib/concurrent-ruby/concurrent/tvar.rb', line 139

def abort_transaction
  raise Transaction::AbortError.new
end

.atomically ⇒ Object

Run a block that reads and writes ‘TVar`s as a single atomic transaction. With respect to the value of `TVar` objects, the transaction is atomic, in that it either happens or it does not, consistent, in that the `TVar` objects involved will never enter an illegal state, and isolated, in that transactions never interfere with each other. You may recognise these properties from database transactions.

There are some very important and unusual semantics that you must be aware of:

  • Most importantly, the block that you pass to atomically may be executed

    more than once. In most cases your code should be free of
side-effects, except for via TVar.

  • If an exception escapes an atomically block it will abort the transaction.

  • It is undefined behaviour to use callcc or Fiber with atomically.

  • If you create a new thread within an atomically, it will not be part of

    the transaction. Creating a thread counts as a side-effect.

Transactions within transactions are flattened to a single transaction.

Examples:

a = new TVar(100_000)
b = new TVar(100)

Concurrent::atomically do
  a.value -= 10
  b.value += 10
end

Raises:

  • (ArgumentError) 


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# File 'lib/concurrent-ruby/concurrent/tvar.rb', line 82

def atomically
  raise ArgumentError.new('no block given') unless block_given?

  # Get the current transaction

  transaction = Transaction::current

  # Are we not already in a transaction (not nested)?

  if transaction.nil?
    # New transaction

    begin
      # Retry loop

      loop do

        # Create a new transaction

        transaction = Transaction.new
        Transaction::current = transaction

        # Run the block, aborting on exceptions

        begin
          result = yield
        rescue Transaction::AbortError => e
          transaction.abort
          result = Transaction::ABORTED
        rescue Transaction::LeaveError => e
          transaction.abort
          break result
        rescue => e
          transaction.abort
          raise e
        end
        # If we can commit, break out of the loop

        if result != Transaction::ABORTED
          if transaction.commit
            break result
          end
        end
      end
    ensure
      # Clear the current transaction

      Transaction::current = nil
    end
  else
    # Nested transaction - flatten it and just run the block

    yield
  end
end

.call_dataflow(method, executor, *inputs, &block) ⇒ Object

Raises:

  • (ArgumentError) 


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# File 'lib/concurrent-ruby/concurrent/dataflow.rb', line 56

def call_dataflow(method, executor, *inputs, &block)
  raise ArgumentError.new('an executor must be provided') if executor.nil?
  raise ArgumentError.new('no block given') unless block_given?
  unless inputs.all? { |input| input.is_a? IVar }
    raise ArgumentError.new("Not all dependencies are IVars.\nDependencies: #{ inputs.inspect }")
  end

  result = Future.new(executor: executor) do
    values = inputs.map { |input| input.send(method) }
    block.call(*values)
  end

  if inputs.empty?
    result.execute
  else
    counter = DependencyCounter.new(inputs.size) { result.execute }

    inputs.each do |input|
      input.add_observer counter
    end
  end

  result
end

.create_simple_logger(level = Logger::FATAL, output = $stderr) ⇒ Logger

Returns Logger with provided level and output.

Returns:

  • (Logger) —

    Logger with provided level and output.



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# File 'lib/concurrent-ruby/concurrent/configuration.rb', line 20

def self.create_simple_logger(level = Logger::FATAL, output = $stderr)
  # TODO (pitr-ch 24-Dec-2016): figure out why it had to be replaced, stdlogger was deadlocking
  lambda do |severity, progname, message = nil, &block|
    return false if severity < level

    message           = block ? block.call : message
    formatted_message = case message
                        when String
                          message
                        when Exception
                          format "%s (%s)\n%s",
                                 message.message, message.class, (message.backtrace || []).join("\n")
                        else
                          message.inspect
                        end

    output.print format "[%s] %5s -- %s: %s\n",
                        Time.now.strftime('%Y-%m-%d %H:%M:%S.%L'),
                        Logger::SEV_LABEL[severity],
                        progname,
                        formatted_message
    true
  end
end

.create_stdlib_logger(level = Logger::FATAL, output = $stderr) ⇒ Logger

Deprecated.

Returns Logger with provided level and output.

Returns:

  • (Logger) —

    Logger with provided level and output.



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# File 'lib/concurrent-ruby/concurrent/configuration.rb', line 52

def self.create_stdlib_logger(level = Logger::FATAL, output = $stderr)
  logger           = Logger.new(output)
  logger.level     = level
  logger.formatter = lambda do |severity, datetime, progname, msg|
    formatted_message = case msg
                        when String
                          msg
                        when Exception
                          format "%s (%s)\n%s",
                                 msg.message, msg.class, (msg.backtrace || []).join("\n")
                        else
                          msg.inspect
                        end
    format "[%s] %5s -- %s: %s\n",
           datetime.strftime('%Y-%m-%d %H:%M:%S.%L'),
           severity,
           progname,
           formatted_message
  end

  lambda do |loglevel, progname, message = nil, &block|
    logger.add loglevel, message, progname, &block
  end
end

.dataflow(*inputs) {|inputs| ... } ⇒ Object

Dataflow allows you to create a task that will be scheduled when all of its data dependencies are available.

Parameters:

  • inputs (Future) —

    zero or more ‘Future` operations that this dataflow depends upon

Yields:

  • The operation to perform once all the dependencies are met

Yield Parameters:

  • inputs (Future) —

    each of the ‘Future` inputs to the dataflow

Yield Returns:

  • (Object) —

    the result of the block operation

Returns:

  • (Object) —

    the result of all the operations

Raises:

  • (ArgumentError) —

    if no block is given

  • (ArgumentError) —

    if any of the inputs are not ‘IVar`s



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# File 'lib/concurrent-ruby/concurrent/dataflow.rb', line 34

def dataflow(*inputs, &block)
  dataflow_with(Concurrent.global_io_executor, *inputs, &block)
end

.dataflow!(*inputs, &block) ⇒ Object 



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# File 'lib/concurrent-ruby/concurrent/dataflow.rb', line 44

def dataflow!(*inputs, &block)
  dataflow_with!(Concurrent.global_io_executor, *inputs, &block)
end

.dataflow_with(executor, *inputs, &block) ⇒ Object 



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# File 'lib/concurrent-ruby/concurrent/dataflow.rb', line 39

def dataflow_with(executor, *inputs, &block)
  call_dataflow(:value, executor, *inputs, &block)
end

.dataflow_with!(executor, *inputs, &block) ⇒ Object 



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# File 'lib/concurrent-ruby/concurrent/dataflow.rb', line 49

def dataflow_with!(executor, *inputs, &block)
  call_dataflow(:value!, executor, *inputs, &block)
end

.disable_at_exit_handlers! ⇒ Object

Deprecated.

Has no effect since it is no longer needed, see github.com/ruby-concurrency/concurrent-ruby/pull/841.

Note:

this option should be needed only because of ‘at_exit` ordering issues which may arise when running some of the testing frameworks. E.g. Minitest’s test-suite runs itself in ‘at_exit` callback which executes after the pools are already terminated. Then auto termination needs to be disabled and called manually after test-suite ends.

Note:

This method should never be called from within a gem. It should only be used from within the main application and even then it should be used only when necessary.

Disables AtExit handlers including pool auto-termination handlers. When disabled it will be the application programmer’s responsibility to ensure that the handlers are shutdown properly prior to application exit by calling ‘AtExit.run` method.



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# File 'lib/concurrent-ruby/concurrent/configuration.rb', line 131

def self.disable_at_exit_handlers!
  deprecated "Method #disable_at_exit_handlers! has no effect since it is no longer needed, see https://github.com/ruby-concurrency/concurrent-ruby/pull/841."
end

.executor(executor_identifier) ⇒ Executor

General access point to global executors.

Parameters:

Returns:

  • (Executor) 


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# File 'lib/concurrent-ruby/concurrent/configuration.rb', line 166

def self.executor(executor_identifier)
  Options.executor(executor_identifier)
end

.global_fast_executor ⇒ ThreadPoolExecutor

Global thread pool optimized for short, fast operations.

Returns:



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# File 'lib/concurrent-ruby/concurrent/configuration.rb', line 138

def self.global_fast_executor
  GLOBAL_FAST_EXECUTOR.value
end

.global_immediate_executor ⇒ Object 



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# File 'lib/concurrent-ruby/concurrent/configuration.rb', line 149

def self.global_immediate_executor
  GLOBAL_IMMEDIATE_EXECUTOR
end

.global_io_executor ⇒ ThreadPoolExecutor

Global thread pool optimized for long, blocking (IO) tasks.

Returns:



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# File 'lib/concurrent-ruby/concurrent/configuration.rb', line 145

def self.global_io_executor
  GLOBAL_IO_EXECUTOR.value
end

.global_logger ⇒ Object 



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# File 'lib/concurrent-ruby/concurrent/configuration.rb', line 92

def self.global_logger
  GLOBAL_LOGGER.value
end

.global_logger=(value) ⇒ Object 



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# File 'lib/concurrent-ruby/concurrent/configuration.rb', line 96

def self.global_logger=(value)
  GLOBAL_LOGGER.value = value
end

.global_timer_set ⇒ Concurrent::TimerSet

Global thread pool user for global timers.

Returns:



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# File 'lib/concurrent-ruby/concurrent/configuration.rb', line 156

def self.global_timer_set
  GLOBAL_TIMER_SET.value
end

.leave_transaction ⇒ Object

Leave a transaction without committing or aborting - see ‘Concurrent::atomically`.

Raises:



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# File 'lib/concurrent-ruby/concurrent/tvar.rb', line 144

def leave_transaction
  raise Transaction::LeaveError.new
end

.monotonic_time(unit = :float_second) ⇒ Object 



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# File 'lib/concurrent-ruby/concurrent/utility/monotonic_time.rb', line 19

def monotonic_time(unit = :float_second)
  Process.clock_gettime(Process::CLOCK_MONOTONIC, unit)
end

.new_fast_executor(opts = {}) ⇒ Object 



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# File 'lib/concurrent-ruby/concurrent/configuration.rb', line 170

def self.new_fast_executor(opts = {})
  FixedThreadPool.new(
      [2, Concurrent.processor_count].max,
      auto_terminate:  opts.fetch(:auto_terminate, true),
      idletime:        60, # 1 minute
      max_queue:       0, # unlimited
      fallback_policy: :abort, # shouldn't matter -- 0 max queue
      name:            "fast"
  )
end

.new_io_executor(opts = {}) ⇒ Object 



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# File 'lib/concurrent-ruby/concurrent/configuration.rb', line 181

def self.new_io_executor(opts = {})
  CachedThreadPool.new(
      auto_terminate:  opts.fetch(:auto_terminate, true),
      fallback_policy: :abort, # shouldn't matter -- 0 max queue
      name:            "io"
  )
end

.physical_processor_count ⇒ Object 



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# File 'lib/concurrent-ruby/concurrent/utility/processor_counter.rb', line 127

def self.physical_processor_count
  processor_counter.physical_processor_count
end

.processor_count ⇒ Object 



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# File 'lib/concurrent-ruby/concurrent/utility/processor_counter.rb', line 123

def self.processor_count
  processor_counter.processor_count
end

.use_simple_logger(level = Logger::FATAL, output = $stderr) ⇒ Object

Use logger created by #create_simple_logger to log concurrent-ruby messages.



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# File 'lib/concurrent-ruby/concurrent/configuration.rb', line 46

def self.use_simple_logger(level = Logger::FATAL, output = $stderr)
  Concurrent.global_logger = create_simple_logger level, output
end

.use_stdlib_logger(level = Logger::FATAL, output = $stderr) ⇒ Object

Deprecated.

Use logger created by #create_stdlib_logger to log concurrent-ruby messages.



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# File 'lib/concurrent-ruby/concurrent/configuration.rb', line 79

def self.use_stdlib_logger(level = Logger::FATAL, output = $stderr)
  Concurrent.global_logger = create_stdlib_logger level, output
end

Instance Method Details

#exchange(value, timeout = nil) ⇒ Object

Waits for another thread to arrive at this exchange point (unless the current thread is interrupted), and then transfers the given object to it, receiving its object in return. The timeout value indicates the approximate number of seconds the method should block while waiting for the exchange. When the timeout value is ‘nil` the method will block indefinitely.

In some edge cases when a ‘timeout` is given a return value of `nil` may be ambiguous. Specifically, if `nil` is a valid value in the exchange it will be impossible to tell whether `nil` is the actual return value or if it signifies timeout. When `nil` is a valid value in the exchange consider using #exchange! or #try_exchange instead.

Parameters:

  • value (Object) —

    the value to exchange with another thread

  • timeout (Numeric, nil) (defaults to: nil) —

    in seconds, ‘nil` blocks indefinitely

Returns:

  • (Object) —

    the value exchanged by the other thread or ‘nil` on timeout




# File 'lib/concurrent-ruby/concurrent/exchanger.rb', line 340

#exchange!(value, timeout = nil) ⇒ Object

Waits for another thread to arrive at this exchange point (unless the current thread is interrupted), and then transfers the given object to it, receiving its object in return. The timeout value indicates the approximate number of seconds the method should block while waiting for the exchange. When the timeout value is ‘nil` the method will block indefinitely.

On timeout a TimeoutError exception will be raised.

Parameters:

  • value (Object) —

    the value to exchange with another thread

  • timeout (Numeric, nil) (defaults to: nil) —

    in seconds, ‘nil` blocks indefinitely

Returns:

  • (Object) —

    the value exchanged by the other thread

Raises:




# File 'lib/concurrent-ruby/concurrent/exchanger.rb', line 344

#initialize(opts = {}) ⇒ Object

Create a new thread pool.

Options Hash (opts):

  • :fallback_policy (Symbol) — default: :discard —

    the policy for handling new tasks that are received when the queue size has reached ‘max_queue` or the executor has shut down

Raises:

  • (ArgumentError) —

    if ‘:fallback_policy` is not one of the values specified in `FALLBACK_POLICIES`

See Also:




# File 'lib/concurrent-ruby/concurrent/exchanger.rb', line 337

#try_exchange(value, timeout = nil) ⇒ Concurrent::Maybe

Waits for another thread to arrive at this exchange point (unless the current thread is interrupted), and then transfers the given object to it, receiving its object in return. The timeout value indicates the approximate number of seconds the method should block while waiting for the exchange. When the timeout value is ‘nil` the method will block indefinitely.

The return value will be a Maybe set to ‘Just` on success or `Nothing` on timeout.

Examples:


exchanger = Concurrent::Exchanger.new

result = exchanger.exchange(:foo, 0.5)

if result.just?
  puts result.value #=> :bar
else
  puts 'timeout'
end

Parameters:

  • value (Object) —

    the value to exchange with another thread

  • timeout (Numeric, nil) (defaults to: nil) —

    in seconds, ‘nil` blocks indefinitely

Returns:

  • (Concurrent::Maybe) —

    on success a ‘Just` maybe will be returned with the item exchanged by the other thread as `#value`; on timeout a `Nothing` maybe will be returned with TimeoutError as `#reason`




# File 'lib/concurrent-ruby/concurrent/exchanger.rb', line 348