1 files changed, 55 insertions, 0 deletions
diff --git a/lib/canary.rb b/lib/canary.rb
new file mode 100644
index 0000000..afe3a16
--- /dev/null
+++ b/lib/canary.rb
@@ -0,0 +1,55 @@
+# encoding: UTF-8
+require 'logger'
+
+# A little canary class to make sure that threads are are overloaded.
+class Canary
+
+  # Accessor.
+  attr_reader :sleep_time
+
+  # Accessor.
+  attr_reader :threshold
+
+  # Default constructor.
+  def initialize (st=1, log=nil)
+    if Float != st.class and Fixnum != st.class
+      raise ArgumentError.new(
+        "Expected either Fixnum or Float for time to sleep, got #{st.class}.") 
+    end
+    @sleep_time = st
+    @threshold = (0.05 * @sleep_time) + @sleep_time
+    @logger = log
+  end
+
+  # Runs the check.
+  def run
+    loop do
+      self.do_test()
+    end
+  end
+
+  def do_test
+    time_start = Time.now
+    sleep(@sleep_time)
+    time_end = Time.now
+    time_elapsed = (time_end - time_start).abs
+    if @threshold < time_elapsed
+      @logger.fatal("Time elapsed is #{time_elapsed} > #{@threshold} therefore Canary is dead.")
+      return false
+    else
+      @logger.debug("Time elapsed is #{time_elapsed} < #{@threshold} therefore Canary is alive.")
+      return true
+    end
+  end
+
+  # Starts a canary in a thread.
+  def self.start (st=1, log=nil)
+    #Thread.abort_on_exception = true
+    thr = Thread.new() do
+      Thread.current[:name] = "Canary Thread"
+      twiti = Canary.new(st, log)
+      twiti.run()
+    end
+  end
+
+end