Allow for setpgid to be configurable

docs/CONFIGURATION.md

@@ -168,6 +168,18 @@ The following options may be specified (but are generally not needed):
 
   Default: `queues - 1`.
 
+- `setpgid: true or false`
+
+  When enabled, child processes will be made into a group leader with a pgid matching
+  their pid. The child process will no longer be in the foreground process group of
+  its control terminal.
+
+  This can break debugging sessions and interactive terminals inside the worker
+  processes. Set it to `false` if you need to activate a debugging session or read from
+  `STDIN` inside a worker process.
+
+  Default: `true` (enabled)
+
 - `umask: mode`
 
   Sets the file mode creation mask for UNIX sockets.

lib/pitchfork/configurator.rb

@@ -79,6 +79,7 @@ class Configurator
       :client_body_buffer_size => Pitchfork::Const::MAX_BODY,
       :before_service_worker_ready => nil,
       :before_service_worker_exit => nil,
+      :setpgid => false,
     }
     #:startdoc:
 
@@ -207,6 +208,10 @@ def timeout_signal(*args, &block)
       end
     end
 
+    def setpgid(bool)
+      set_bool(:setpgid, bool)
+    end
+
     def spawn_timeout(seconds)
       set_int(:spawn_timeout, seconds, 1)
     end

lib/pitchfork/http_server.rb

@@ -80,7 +80,7 @@ def extend_deadline(extra_time)
     attr_accessor :app, :timeout, :timeout_signal, :soft_timeout, :cleanup_timeout, :spawn_timeout, :worker_processes,
                   :before_fork, :after_worker_fork, :after_mold_fork, :before_service_worker_ready, :before_service_worker_exit,
                   :listener_opts, :children,
-                  :orig_app, :config, :ready_pipe, :early_hints
+                  :orig_app, :config, :ready_pipe, :early_hints, :setpgid
     attr_writer   :after_worker_exit, :before_worker_exit, :after_worker_ready, :after_request_complete,
                   :refork_condition, :after_worker_timeout, :after_worker_hard_timeout, :after_monitor_ready
 
@@ -667,7 +667,7 @@ def spawn_service(service, detach:)
     def spawn_initial_mold
       mold = Worker.new(nil)
       mold.create_socketpair!
-      mold.pid = Pitchfork.clean_fork do
+      mold.pid = Pitchfork.clean_fork(setpgid: setpgid) do
         mold.pid = Process.pid
         @promotion_lock.try_lock
         mold.after_fork_in_child
@@ -1187,7 +1187,7 @@ def fork_sibling(role, &block)
         else # first child
           r.close
           Process.setproctitle("<pitchfork fork_sibling(#{role})>")
-          pid = Pitchfork.clean_fork do
+          pid = Pitchfork.clean_fork(setpgid: setpgid) do
             # detach into a grand child
             w.close
             yield
@@ -1202,7 +1202,7 @@ def fork_sibling(role, &block)
           exit!
         end
       else
-        Pitchfork.clean_fork(&block)
+        Pitchfork.clean_fork(setpgid: setpgid, &block)
       end
     end
 

test/integration/test_configuration.rb

@@ -189,6 +189,48 @@ def test_modify_internals
     assert_clean_shutdown(pid)
   end
 
+  def test_setpgid_true
+    addr, port = unused_port
+
+    pid = spawn_server(app: File.join(ROOT, "test/integration/pid.ru"), config: <<~CONFIG)
+      listen "#{addr}:#{port}"
+      worker_processes 1
+
+      setpgid true
+    CONFIG
+
+    assert_healthy("http://#{addr}:#{port}")
+
+    worker_pid = Net::HTTP.get(URI("http://#{addr}:#{port}")).strip.to_i
+
+    pgid_pid = Process.getpgid(pid)
+    pgid_worker = Process.getpgid(worker_pid)
+
+    refute_equal(pgid_pid, pgid_worker)
+    assert_clean_shutdown(pid)
+  end
+
+  def test_setpgid_false
+    addr, port = unused_port
+
+    pid = spawn_server(app: File.join(ROOT, "test/integration/pid.ru"), config: <<~CONFIG)
+      listen "#{addr}:#{port}"
+      worker_processes 1
+
+      setpgid false
+    CONFIG
+
+    assert_healthy("http://#{addr}:#{port}")
+
+    worker_pid = Net::HTTP.get(URI("http://#{addr}:#{port}")).strip.to_i
+
+    pgid_pid = Process.getpgid(pid)
+    pgid_worker = Process.getpgid(worker_pid)
+
+    assert_equal(pgid_pid, pgid_worker)
+    assert_clean_shutdown(pid)
+  end
+
   def test_at_exit_handlers
     addr, port = unused_port