trddddd · August 13, 2020 23:23 · Aug 13, 2020 · Dec 3, 2008
diff --git a/forking_supervisor.rb b/forking_supervisor.rb
@@ -1,78 +1,80 @@
-#!/usr/bin/env ruby
-#
-# forking supervisor - forks workers and replaces dead workers.
-# start it in one console, send signals to it from another console.
-#
-
-require 'rubygems'
-require 'daemons/daemonize'
-
-
-def logit(msg)
-  if $worker
-    puts "#{Time.now} worker[#{$$}] #{msg}"
-  else
-    puts "#{Time.now} supervisor[#{$$}] #{msg}"
-  end
-end
-
-def myworker
-  # this is your worker, it does something useful
-  loop {
-    logit "ping"
-    sleep 20
-  }
-end
-
-def start_worker_daemon
-  p = Process.fork { $worker = true; myworker }
-  logit "started worker pid=#{p}"
-  p
-end
-
-
-if __FILE__ == $0
-    # starts supervisor
-    Daemonize.daemonize(logfile_name="/tmp/my.log", app_name="foo") if
-      ARGV[0] == '-d'   # do you want supervisor as a daemon?
-
-    logit "started"
-    pids = Array.new
-    workers = 3     # how many workers would you like today?
-    logit "workers = #{workers}"
-    $shutdown = false
-
-    Signal.trap("TERM") {
-      $shutdown = true
-      if $worker
-        # can do some worker cleanup here
-        logit "Caught SIGTERM. Exiting."
-      else
-        logit "caught SIGTERM. Signaling child processes: #{pids.inspect}"
-        pids.each { |pid|
-          logit "sending SIGTERM to pid=#{pid}"
-          Process.kill('TERM', pid)
-          Process.waitpid(pid)
-          logit "pid=#{pid} died."
-        }
-        logit "All child processes died."
-        # can do some supervisor cleanup here
-      end
-      exit
-    }
-
-    Signal.trap('CLD') {
-      unless $shutdown
-        pids.delete(Process.wait)
-        pids << start_worker_daemon
-      end
-    }
-
-    while pids.size < workers
-      pids << start_worker_daemon
-    end
-
-    loop { sleep 0x1000000 } rescue exit
-
-end
-
+class Daemons
+  def initialize
+    @num_worker = 3
+    @worker_pids = []
+    @signal_queue = []
+    @handle_signals = %i[INT CLD]
+    @self_pipe_reader, @self_pipe_writer = IO.pipe
+  end
+
+  def start
+    $PROGRAM_NAME = 'Daemons (Parent)'
+    spawn_workers
+    trap_signals
+
+    loop do
+      IO.select([@self_pipe_reader])
+      @self_pipe_reader.read(1)
+
+      case @signal_queue.shift
+      when :INT
+        graceful_shutdown
+      when :CLD
+        respawn_worker
+      end
+    end
+  end
+
+  def respawn_worker
+    @worker_pids.delete(Process.wait)
+    spawn_worker(99)
+    puts 'CLD'
+  end
+
+  def graceful_shutdown
+    @worker_pids.each do |wpid|
+      Process.kill(:INT, wpid)
+    end
+
+    sleep 1
+    @worker_pids.each do |wpid|
+      Process.kill(:KILL, wpid) unless Process.waitpid(wpid, Process::WNOHANG)
+    end
+
+    exit
+  end
+
+  def spawn_workers
+    @num_worker.times do |num|
+      spawn_worker(num)
+    end
+  end
+
+  def trap_signals
+    @handle_signals.each do |sig|
+      Signal.trap(sig) do
+        @signal_queue << sig
+        @self_pipe_writer.write('.')
+      end
+    end
+  end
+
+  def spawn_worker(num)
+    @worker_pids << Process.fork do
+      $PROGRAM_NAME = "Daemons (Worker ##{num})"
+
+      Signal.trap(:INT) { exit }
+
+      worker_loop
+    end
+  end
+
+  def worker_loop
+    loop do
+      sleep 60
+      puts 'KEKA'
+    end
+  end
+end
+
+Daemons.new.start
diff --git a/forking_supervisor.rb b/forking_supervisor.rb
@@ -0,0 +1,78 @@
+#!/usr/bin/env ruby
+#
+# forking supervisor - forks workers and replaces dead workers.
+# start it in one console, send signals to it from another console.
+#
+
+require 'rubygems'
+require 'daemons/daemonize'
+
+
+def logit(msg)
+  if $worker
+    puts "#{Time.now} worker[#{$$}] #{msg}"
+  else
+    puts "#{Time.now} supervisor[#{$$}] #{msg}"
+  end
+end
+
+def myworker
+  # this is your worker, it does something useful
+  loop {
+    logit "ping"
+    sleep 20
+  }
+end
+
+def start_worker_daemon
+  p = Process.fork { $worker = true; myworker }
+  logit "started worker pid=#{p}"
+  p
+end
+
+
+if __FILE__ == $0
+    # starts supervisor
+    Daemonize.daemonize(logfile_name="/tmp/my.log", app_name="foo") if
+      ARGV[0] == '-d'   # do you want supervisor as a daemon?
+
+    logit "started"
+    pids = Array.new
+    workers = 3     # how many workers would you like today?
+    logit "workers = #{workers}"
+    $shutdown = false
+
+    Signal.trap("TERM") {
+      $shutdown = true
+      if $worker
+        # can do some worker cleanup here
+        logit "Caught SIGTERM. Exiting."
+      else
+        logit "caught SIGTERM. Signaling child processes: #{pids.inspect}"
+        pids.each { |pid|
+          logit "sending SIGTERM to pid=#{pid}"
+          Process.kill('TERM', pid)
+          Process.waitpid(pid)
+          logit "pid=#{pid} died."
+        }
+        logit "All child processes died."
+        # can do some supervisor cleanup here
+      end
+      exit
+    }
+
+    Signal.trap('CLD') {
+      unless $shutdown
+        pids.delete(Process.wait)
+        pids << start_worker_daemon
+      end
+    }
+
+    while pids.size < workers
+      pids << start_worker_daemon
+    end
+
+    loop { sleep 0x1000000 } rescue exit
+
+end
+
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