Post spawn docs

Co-authored-by: David Hoover <hooverd@arizona.edu>

django_q/cluster.py

@@ -39,7 +39,7 @@ from django_q.conf import (
 from django_q.humanhash import humanize
 from django_q.models import Schedule, Success, Task
 from django_q.queues import Queue
-from django_q.signals import post_execute, pre_execute
+from django_q.signals import post_execute, post_spawn, pre_execute
 from django_q.signing import BadSignature, SignedPackage
 from django_q.status import Stat, Status
 
@@ -481,6 +481,7 @@ def worker(
         _("%(proc_name)s ready for work at %(id)s")
         % {"proc_name": proc_name, "id": current_process().pid}
     )
+    post_spawn.send(sender="django_q", proc_name=proc_name)
     if setproctitle:
         setproctitle.setproctitle(f"qcluster {proc_name} idle")
     task_count = 0

django_q/signals.py

@@ -31,6 +31,8 @@ def call_hook(sender, instance, **kwargs):
                 % {"hook": instance.hook, "name": instance.name, "error": str(e)}
             )
 
+# args: proc_name
+post_spawn = Signal()
 
 # args: task
 pre_enqueue = Signal()

docs/signals.rst

@@ -13,6 +13,12 @@ Before enqueuing a task
 The ``django_q.signals.pre_enqueue`` signal is emitted before a task is
 enqueued. The task dictionary is given as the ``task`` argument.
 
+After spawning a worker process
+"""""""""""""""""""""""""""""""
+
+The ``django_q.signals.post_spawn`` signal is emitted after a worker process has
+spawned. The process name is given as the ``proc_name`` argument (string).
+
 Before executing a task
 """""""""""""""""""""""
 
@@ -37,7 +43,7 @@ Connecting to a Django Q2 signal is done the same as any other Django
 signal::
 
     from django.dispatch import receiver
-    from django_q.signals import pre_enqueue, pre_execute, post_execute
+    from django_q.signals import pre_enqueue, pre_execute, post_execute, post_spawn
 
     @receiver(pre_enqueue)
     def my_pre_enqueue_callback(sender, task, **kwargs):
@@ -51,4 +57,8 @@ signal::
     def my_post_execute_callback(sender, task, **kwargs):
         print(f"Task {task['name']} was executed with result {task['result']}")
 
+    @receiver(post_spawn)
+    def my_post_spawn_callback(sender, proc_name, **kwargs):
+        print(f"Process {proc_name} has spawned")
+