Class: ThreadLimiter
- Inherits:
-
Object
- Object
- ThreadLimiter
- Defined in:
- lib/threadlimiter/threadlimiter.rb,
lib/threadlimiter/version.rb
Overview
Fork threads like Thread.fork, but limit the number of concurrently running threads.
ThreadLimiter isn’t a thread pool. Each fork really starts a new thread.
Constant Summary collapse
- VERSION =
"0.2.1"
Class Method Summary collapse
-
.handle_clusters(enumeration, number_of_clusters, method_name, &block) ⇒ Object
:nodoc:.
-
.open(*args) ⇒ Object
Create and use a new ThreadLimiter and wait for all threads to finish.
Instance Method Summary collapse
-
#fork(*args, &block) ⇒ Object
Fork a thread.
-
#initialize(limit, options = {}) ⇒ ThreadLimiter
constructor
Initialize the ThreadLimiter.
-
#wait ⇒ Object
Wait for all threads to finish.
Constructor Details
#initialize(limit, options = {}) ⇒ ThreadLimiter
Initialize the ThreadLimiter. The optional parameter limit is the maximum number of concurrently running threads. Set limit to -1 to fork threads without limiting the number of concurrently running threads. Set limit to 0 to join the newly created thread immediately, mimicking no-forking. Set options to true to start the new thread before waiting for resources.
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# File 'lib/threadlimiter/threadlimiter.rb', line 25 def initialize(limit, ={}) @limit = limit # The maximum number of concurrently running threads. @running = 0 # The number of currently running threads. @noblock = [:noblock] @mutex = Mutex.new @cv = ConditionVariable.new end |
Class Method Details
.handle_clusters(enumeration, number_of_clusters, method_name, &block) ⇒ Object
:nodoc:
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# File 'lib/threadlimiter/threadlimiter.rb', line 64 def self.handle_clusters(enumeration, number_of_clusters, method_name, &block) # :nodoc: clusters = [] # One cluster per fork. last_pos = -1 res = [] enumeration.each do |object| last_pos += 1 (clusters[last_pos%number_of_clusters] ||= []) << object end clusters.__send__(method_name, -1) do |cluster| cluster.collect do |object| if block.arity > 1 and object.kind_of?(Enumerable) yield(*object.to_a) else yield(object) end end end.collect do |cluster| cluster + (cluster.length == clusters[0].length ? [] : [nil]) # Add padding nil, in order to be able to transpose end.transpose.each do |array| res.concat(array) end res[0..last_pos] # Remove padding nil. end |
.open(*args) ⇒ Object
Create and use a new ThreadLimiter and wait for all threads to finish.
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# File 'lib/threadlimiter/threadlimiter.rb', line 9 def self.open(*args) thread_limiter = new(*args) begin yield(thread_limiter) ensure thread_limiter.wait end end |
Instance Method Details
#fork(*args, &block) ⇒ Object
Fork a thread. The given block is run within the thread. It behaves like Thread.fork(). In fact, it invokes Thread.fork() and returns its result. The list of arguments is passed to Thread.fork().
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# File 'lib/threadlimiter/threadlimiter.rb', line 40 def fork(*args, &block) if @limit < 0 Thread.fork do yield(*args) end elsif @limit == 0 Thread.fork do yield(*args) end.join # Because ThreadLimiter#fork() should return a new Thread. else cv_wait unless @noblock Thread.fork do cv_wait if @noblock begin yield(*args) ensure cv_signal end end end end |
#wait ⇒ Object
Wait for all threads to finish.
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# File 'lib/threadlimiter/threadlimiter.rb', line 94 def wait @mutex.synchronize do while @running > 0 @cv.wait(@mutex) end end self end |