adding some additional celery debugging options to readme

README.md

@@ -24,3 +24,55 @@ Use the flower dashboard at: `0.0.0.0:5557`
 `CELERY_TASK_ALWAYS_EAGER: bool = True` will synchronously execute the celery tasks. This allows us to use things like `breakpoint()` to enter a debugger within the execution context of the task.
 
 Since the app currently uses the fastapi application config for celery config, add `CELERY_TASK_ALWAYS_EAGER=True` to the config class if needed. You don't need to run the worker, message broker, or result backend processes to debug your code. It will process the task within
+
+### Using rdb in Docker Compose environment
+
+Celery ships with [an extension to pdb called rdb](https://docs.celeryq.dev/en/stable/userguide/debugging.html) that will allow for remote debugging using a tool like `telnet`.
+
+To use this with your dockerized app you must have `telnet` installed in your container or export the debug port on the container by setting `CELERY_RDB_PORT` in config and adjusting the compose file accordingly. By default the remote debugging is only available at localhost. It is possible to access this remote session on another host using `CELERY_RDB_HOST` also.
+
+Set the breakpoint like you would with pdb:
+
+```
+def foo():
+    from celery.contrib import rdb
+    rdb.set_trace()
+```
+
+Run your dockerized environment
+
+```
+docker compose -d up
+docker compose -f logs
+```
+
+Trigger the execution path to the break point:
+
+```
+docker compose exec web bash
+python
+>> from main import app
+>> from project.users.tasks import divide
+>> divide.delay(1,2)
+```
+
+You will see a debug session with connection details displayed in the logs. Now you just need to connect
+to the remote session. Since this is running in a docker container that doesn't have the port exposed you
+will need to exec into the container and use telenet.
+
+```
+docker compose exec celery_work bash
+telenet 127.0.0.1 <randomish port>
+>>(Pdb)
+>>(Pdb) help
+```
+
+It is also possible to set a [signal to enter a remote debugger](https://docs.celeryq.dev/en/stable/userguide/debugging.html#enabling-the-break-point-signal) using by sending a `SIGUSR2`.
+
+```
+CELERY_RDBSIG=1 celery worker -l INFO
+```
+
+```
+kill -USR2 <celery_pid>
+```

compose/local/fastapi/Dockerfile

@@ -22,21 +22,21 @@ COPY ./compose/local/fastapi/entrypoint /entrypoint
 RUN sed -i 's/\r$//g' /entrypoint
 RUN chmod +x /entrypoint
 
-COPY ./compose/local/fastapi/start /start-web
+COPY ./compose/local/fastapi/start.sh /start-web.sh
-RUN sed -i 's/\r$//g' /start-web
+RUN sed -i 's/\r$//g' /start-web.sh
-RUN chmod +x /start-web
+RUN chmod +x /start-web.sh
 
-COPY ./compose/local/fastapi/celery/worker/start /start-celeryworker
+COPY ./compose/local/fastapi/celery/worker/start.sh /start-celeryworker.sh
-RUN sed -i 's/\r$//g' /start-celeryworker
+RUN sed -i 's/\r$//g' /start-celeryworker.sh
-RUN chmod +x /start-celeryworker
+RUN chmod +x /start-celeryworker.sh
 
-COPY ./compose/local/fastapi/celery/beat/start /start-celerybeat
+COPY ./compose/local/fastapi/celery/beat/start.sh /start-celerybeat.sh
-RUN sed -i 's/\r$//g' /start-celerybeat
+RUN sed -i 's/\r$//g' /start-celerybeat.sh
-RUN chmod +x /start-celerybeat
+RUN chmod +x /start-celerybeat.sh
 
-COPY ./compose/local/fastapi/celery/flower/start /start-flower
+COPY ./compose/local/fastapi/celery/flower/start.sh /start-flower.sh
-RUN sed -i 's/\r$//g' /start-flower
+RUN sed -i 's/\r$//g' /start-flower.sh
-RUN chmod +x /start-flower
+RUN chmod +x /start-flower.sh
 
 WORKDIR /app
 

docker-compose.yml

@@ -7,7 +7,7 @@ services:
       dockerfile: ./compose/local/fastapi/Dockerfile
     image: fastapi_celery_example_web
     # '/start' is the shell script used to run the service
-    command: /start-web
+    command: /start-web.sh
     # this volume is used to map the files and folders on the host to the container
     # so if we change code on the host, code in the docker container will also be changed
     volumes:
@@ -37,7 +37,7 @@ services:
       context: .
       dockerfile: ./compose/local/fastapi/Dockerfile
     image: fastapi_celery_example_celery_worker
-    command: /start-celeryworker
+    command: /start-celeryworker.sh
     volumes:
       - .:/app
     env_file:
@@ -51,7 +51,7 @@ services:
       context: .
       dockerfile: ./compose/local/fastapi/Dockerfile
     image: fastapi_celery_example_celery_beat
-    command: /start-celerybeat
+    command: /start-celerybeat.sh
     volumes:
       - .:/app
     env_file:
@@ -65,7 +65,7 @@ services:
       context: .
       dockerfile: ./compose/local/fastapi/Dockerfile
     image: fastapi_celery_example_celery_flower
-    command: /start-flower
+    command: /start-flower.sh
     volumes:
       - .:/app
     env_file:

project/users/tasks.py

@@ -9,6 +9,7 @@ from celery import shared_task
 
 @shared_task
 def divide(x, y):
+
     import time
 
     time.sleep(5)