Class: Charming::Tasks::ThreadedExecutor

Inherits:
Object
  • Object
show all
Defined in:
lib/charming/tasks/threaded_executor.rb

Overview

ThreadedExecutor runs submitted tasks on background Ruby threads. Each submission creates a new thread that invokes the block and pushes the resulting TaskEvent onto the shared queue. Threads are tracked so ‘shutdown` can wait (or kill) in-flight work, and tracked by name so `cancel` can interrupt a specific task.

Instance Method Summary collapse

Constructor Details

#initialize(queue) ⇒ ThreadedExecutor

queue is the thread-safe Queue (typically ‘runtime.@task_queue`) into which completed TaskEvents are pushed.



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# File 'lib/charming/tasks/threaded_executor.rb', line 12

def initialize(queue)
  @queue = queue
  @threads = []
  @threads_by_name = {}
  @mutex = Mutex.new
  @shutting_down = false
end

Instance Method Details

#cancel(name) ⇒ Object

Cancels the named in-flight task by raising Tasks::Cancelled in its thread. The task completes with a TaskEvent whose error is the Cancelled exception. No-op when the task isn’t running.



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# File 'lib/charming/tasks/threaded_executor.rb', line 40

def cancel(name)
  thread = @mutex.synchronize { @threads_by_name[name.to_sym] }
  return unless thread&.alive?

  thread.raise(Cancelled, "task #{name} cancelled")
  nil
end

#shutdown(timeout: 2.0) ⇒ Object

Waits up to timeout seconds for in-flight threads to finish, then kills any remaining live threads. Refuses new submissions once called.



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# File 'lib/charming/tasks/threaded_executor.rb', line 50

def shutdown(timeout: 2.0)
  threads = @mutex.synchronize do
    @shutting_down = true
    @threads.dup
  end
  threads.each { |thread| thread.join(timeout) }
  threads.each do |thread|
    next unless thread.alive?

    thread.kill
    thread.join(0)
  end
end

#submit(name, timeout: nil, &block) ⇒ Object

Wraps block in a Task and spawns a new thread to invoke it. The thread’s return value (or rescued exception) is pushed onto the queue as a TaskEvent. Blocks that accept an argument receive a Progress reporter. timeout (seconds) cancels the task when exceeded. Returns nil immediately. Raises if called after shutdown has begun.



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# File 'lib/charming/tasks/threaded_executor.rb', line 25

def submit(name, timeout: nil, &block)
  task = Task.new(name: name.to_sym, block: block, timeout: timeout)
  @mutex.synchronize do
    raise "cannot submit task after shutdown" if @shutting_down

    thread = Thread.new(task) { |t| @queue << run(t) }
    @threads << thread
    @threads_by_name[task.name] = thread
  end
  nil
end