process_handler.rb in consul-templaterb-1.24.0

- old
+ new
@@ -1,59 +1,69 @@
 module Consul
   module Async
+    # Exception thrown when process does not exists
     class ProcessDoesNotExist < StandardError
     end
+
+    # Handle the full lifecycle of a process and allows to forward
+    # Posix signals to child process when needed.
     class ProcessHandler
       attr_reader :command, :sig_reload, :sig_term, :pid, :exit_status
       def initialize(command, sig_reload: 'HUP', sig_term: 'TERM')
         raise 'empty sig_term is not supported' unless sig_term
+
         @command = command
         @sig_reload = sig_reload
         @sig_term = sig_term
         @pid = nil
         @exit_status = nil
       end
 
       def start
         return pid unless pid.nil?
+
         @pid = Process.spawn(command)
       end
 
       def reload
         return if sig_reload.nil?
-        STDERR.puts "Sending SIG #{sig_reload} to #{pid}..."
+
+        warn "Sending SIG #{sig_reload} to #{pid}..."
         begin
           Process.kill(sig_reload, pid)
         rescue Errno::ESRCH => e
-          STDERR.puts "*** Process #{pid} has already been killed: #{e.inspect}"
+          warn "*** Process #{pid} has already been killed: #{e.inspect}"
           raise e
         end
       end
 
       def kill
         return exit_status if pid.nil?
+
         the_pid = pid
         @pid = nil
-        STDERR.puts "[KILL] Sending SIG #{sig_term} to #{the_pid}..."
+        warn "[KILL] Sending SIG #{sig_term} to #{the_pid}..."
         begin
-          STDERR.puts "[KILL] waiting for #{the_pid}..."
+          warn "[KILL] waiting for #{the_pid}..."
           Process.kill(sig_term, the_pid)
         rescue Errno::ESRCH
-          STDERR.puts "[KILL] *** Process #{the_pid} has already been killed"
+          warn "[KILL] *** Process #{the_pid} has already been killed"
         end
         begin
           _pid, @exit_status = Process.waitpid2 the_pid
         rescue SystemCallError
-          STDERR.puts "[KILL] *** UNEXPECTED ERROR *** Failed to get return code for #{the_pid}"
+          warn "[KILL] *** UNEXPECTED ERROR *** Failed to get return code for #{the_pid}"
         end
         exit_status
       end
 
       def process_status
         raise ProcessDoesNotExist, 'No child process' if pid.nil?
+
         begin
           cpid, result = Process.waitpid2(pid, Process::WNOHANG)
           raise ProcessDoesNotExist, "Unexpected PID: #{cpid}, was expecting #{pid}" unless cpid.nil? || cpid == pid
+
           result
         rescue Errno::ECHILD => e
           e2 = ProcessDoesNotExist.new e
           raise e2, "ChildProcess has been killed: #{e.message}", e.backtrace
         end