litescheduler.rb in litescheduler-0.2.0

- old
+ new
@@ -1,8 +1,102 @@
 # frozen_string_literal: true
 
 require_relative "litescheduler/version"
+require "singleton"
 
-module Litescheduler
-  class Error < StandardError; end
-  # Your code goes here...
+class Litescheduler
+  include Singleton
+
+  attr_reader :environment, :scheduler, :max_contexts, :storage, :context, :mutex
+
+  def initialize
+    @environment = detect_environment
+    @scheduler = detect_scheduler
+    @max_contexts = detect_max_contexts
+    @storage = detect_storage
+    @context = detect_context
+    # a single mutex per process (is that ok?)
+    @mutex = Thread::Mutex.new
+  end
+
+  # spawn a new execution context
+  def spawn(&block)
+    case @scheduler
+    when :fiber then Fiber.schedule(&block)
+    when :polyphony then spin(&block)
+    when :iodine then Thread.new(&block)
+    when :threaded then Thread.new(&block)
+    else
+      raise StandardError.new("Unknown scheduler: `#{@scheduler}`")
+    end
+  end
+
+  # switch the execution context to allow others to run
+  def switch
+    if @scheduler == :fiber
+      Fiber.scheduler.yield
+      true
+    elsif @scheduler == :polyphony
+      Fiber.current.schedule
+      Thread.current.switch_fiber
+      true
+    else
+      # Thread.pass
+      false
+    end
+  end
+
+  # bold assumption, we will only synchronize threaded code
+  # this is a no-op for fibers
+  def synchronize(&block)
+    # do nothing, just run the block as is
+    return yield if @scheduler == :fiber
+    return yield if @scheduler == :polyphony
+
+    @mutex.synchronize(&block)
+  end
+
+  private
+
+  # Detect the Rack or Rails environment.
+  def detect_environment
+    return Rails.env if defined? Rails
+    return ENV["RACK_ENV"] if ENV.key?("RACK_ENV")
+    return ENV["APP_ENV"] if ENV.key?("APP_ENV")
+
+    "development"
+  end
+
+  # identify which scheduler we are running in
+  # we currently support :fiber, :polyphony, :iodine & :threaded
+  # in the future we might want to expand to other schedulers
+  def detect_scheduler
+    return :fiber if Fiber.scheduler
+    return :polyphony if defined? Polyphony
+    return :iodine if defined? Iodine
+
+    :threaded
+  end
+
+  def detect_max_contexts
+    return 50 if scheduler == :fiber
+    return 50 if scheduler == :polyphony
+
+    5
+  end
+
+  def detect_storage
+    if scheduler == :fiber || scheduler == :poylphony
+      Fiber.current.storage
+    else
+      Thread.current
+    end
+  end
+
+  def detect_context
+    if scheduler == :fiber || scheduler == :poylphony
+      Fiber.current
+    else
+      Thread.current
+    end
+  end
 end