b9559fc934
Currently, LMS uses 3 Celery workers: lms_default_1, lms_high_1 and lms_high_mem_1. Each Celery worker sends messages to a single queue: edx.core.default, edx.core.high and edx.core.high_mem, respectively. The number of child processes per Celery worker is set to 1. Due to this configuration, any task in a queue blocks all other tasks. Currently, the Celery check task submitted by the /heartbeat?extended LMS HTTP API endpoint runs in the default queue. When some slow task (eg course grades creation) is sent to the default queue, it will block the Celery check task, which will expire and the heartbeat endpoint will fail. This patch moves the task to another queue which has only shorter tasks and in which this problem will not occur. Use a Django setting for the Celery check task routing key so that it can be overriden by individual OpenEDX instances via JSON env files.
Open edX -------- This is the root package for Open edX. The intent is that all importable code from Open edX will eventually live here, including the code in the lms, cms, and common directories. If you're adding a new Django app, place it in core/djangoapps. If you're adding utilities that require Django, place them in core/djangolib. If you're adding code that defines no Django models or views of its own but is widely useful, put it in core/lib. Note: All new code should be created in this package, and the legacy code will be moved here gradually. For now the code is not structured like this, and hence legacy code will continue to live in a number of different packages.