1 files changed, 121 insertions, 0 deletions
diff --git a/watchdog.rb b/watchdog.rb
new file mode 100755
index 0000000..e6b82e8
--- /dev/null
+++ b/watchdog.rb
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+#!/usr/bin/env ruby
+#
+#  watchdog.rb: Watchdog component.
+#
+#  Copyright (C) 2011 VMware, Inc.
+# 
+#  Permission is hereby granted, free of charge, to any person obtaining a copy
+#  of this software and associated documentation files (the "Software"), to deal
+#  in the Software without restriction, including without limitation the rights
+#  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+#  copies of the Software, and to permit persons to whom the Software is
+#  furnished to do so, subject to the following conditions:
+#  
+#  The above copyright notice and this permission notice shall be included in
+#  all copies or substantial portions of the Software.
+# 
+#  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+#  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+#  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+#  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+#  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+#  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+#  THE SOFTWARE.
+
+require 'thread'
+require 'ffi-rzmq'
+require 'socket'
+
+trap("INT") { exit }
+trap("TERM") { exit }
+def raise_if_error(rc)
+  unless ZMQ::Util.resultcode_ok?(rc)
+    raise "ZMQ Error: #{ZMQ::Util.error_string}"
+  end
+end
+
+if ARGV.length != 1
+  print "usage: watchdog <notifier-host>\n"
+  exit 1
+end
+
+notifier_ep = "tcp://#{ARGV[0]}:7770"
+control_ep = "tcp://*:7772"
+
+ctx = ZMQ::Context.new()
+notifier_sock = ctx.socket(ZMQ::PUB)
+rc = notifier_sock.connect(notifier_ep)
+raise_if_error(rc)
+
+control_sock = ctx.socket(ZMQ::PULL)
+rc = control_sock.bind(control_ep)
+raise_if_error(rc)
+
+poller = ZMQ::Poller.new
+poller.register_readable(control_sock)
+
+children = {}
+
+#  Delete process if it went away
+trap("CHLD") do
+  pid = Process.wait
+  children.each do |k, v|
+    if v[:pid] == pid
+      children.delete(k)
+    end
+  end
+end
+
+#  Kill any children on exit
+trap("TERM") do
+  children.each do |k, v|
+    Process.kill("KILL", v[:pid])
+  end
+end
+
+#
+#  Main loop
+#
+loop do
+  ready = poller.poll(1)
+
+  #  Process commands, if any.
+  if (ready == 1 && poller.readables.include?(control_sock))
+    msg = ''
+    rc = control_sock.recv_string(msg)
+    raise_if_error(rc)
+    if (msg =~ /^START (.+)$/)
+      command = $1
+      key = command.split()[0]
+      unless children.has_key?(key)
+        exec_command = "./" + key
+        if File.exists?(exec_command) && File.executable?(exec_command)
+          children[key] = {}
+          children[key][:pid] = Process.spawn("./" + command)
+          children[key][:command] = command
+        end
+      end
+    elsif (msg =~ /^STOP (.+)$/)
+      command = $1
+      key = command.split()[0]
+      if children.has_key?(key)
+        Process.kill("KILL", children[key][:pid])
+        while children.has_key?(key)
+          # nothing  
+        end
+      end
+    end
+  #  Otherwise, send out status messages to notifier.
+  else
+    status = "WATCHDOG ALIVE " + Socket.gethostname + " " + Time.now.to_f.to_s
+    rc = notifier_sock.send_string(status)
+    raise_if_error(rc)
+    children.each do |k, v|
+      status = "WATCHDOG RUNNING " + Socket.gethostname + \
+        " " + Time.now.to_f.to_s + " " + v[:command]
+      rc = notifier_sock.send_string(status)
+      raise_if_error(rc)
+    end
+  end
+end
+