temp: Enable Celery distributed tracing in stage edxapp

Datadog Support suggested that we try enabling this to see if it changes
anything about the orphaned spans on the edxapp workers (unexpected
top-level spans that are not `operation_name:celery.run`, but instead are
other spans that have lost their parent association).

Just going to enable this on stage so we don't mess with traces in prod,
for now.

See edx/edx-arch-experiments#822

playbooks/roles/edxapp/templates/edx/app/edxapp/cms.sh.j2

@@ -21,6 +21,14 @@ export DD_TRACE_LOG_STREAM_HANDLER=false
 # Suppress middleware spans because there are about 100 for each request.
 # Remove (or set to true) for debugging.
 export DD_DJANGO_INSTRUMENT_MIDDLEWARE=false
+
+{% if COMMON_ENVIRONMENT == "stage" %}
+# Temporary 2025-01-09: Enable Celery distributed tracing to see if it
+# has an effect on the remaining orphaned spans.
+# https://github.com/edx/edx-arch-experiments/issues/822
+export DD_CELERY_DISTRIBUTED_TRACING=true
+{% endif %}
+
 {% endif -%}
 
 # We want to be able to toggle this on separately from DD in general.
@@ -54,4 +62,4 @@ source {{ edxapp_app_dir }}/edxapp_env
 exec {{ executable }} -c {{ edxapp_app_dir }}/cms_gunicorn.py {{ EDXAPP_CMS_GUNICORN_EXTRA }} cms.wsgi --log-file {{ edxapp_gunicorn_log_dir[1] }}/edx.log
 {% else %}
 exec {{ executable }} -c {{ edxapp_app_dir }}/cms_gunicorn.py {{ EDXAPP_CMS_GUNICORN_EXTRA }} cms.wsgi
-{% endif %}
+{% endif %}

playbooks/roles/edxapp/templates/edx/app/edxapp/lms.sh.j2

@@ -22,6 +22,13 @@ export DD_TRACE_LOG_STREAM_HANDLER=false
 # Remove (or set to true) for debugging.
 export DD_DJANGO_INSTRUMENT_MIDDLEWARE=false
 
+{% if COMMON_ENVIRONMENT == "stage" %}
+# Temporary 2025-01-09: Enable Celery distributed tracing to see if it
+# has an effect on the remaining orphaned spans.
+# https://github.com/edx/edx-arch-experiments/issues/822
+export DD_CELERY_DISTRIBUTED_TRACING=true
+{% endif %}
+
 {% endif -%}
 
 # We want to be able to toggle this on separately from DD in general.

playbooks/roles/edxapp/templates/edx/app/edxapp/worker.sh.j2

@@ -21,6 +21,14 @@ export DD_TRACE_LOG_STREAM_HANDLER=false
 # Suppress middleware spans because there are about 100 for each request.
 # Remove (or set to true) for debugging.
 export DD_DJANGO_INSTRUMENT_MIDDLEWARE=false
+
+{% if COMMON_ENVIRONMENT == "stage" %}
+# Temporary 2025-01-09: Enable Celery distributed tracing to see if it
+# has an effect on the remaining orphaned spans.
+# https://github.com/edx/edx-arch-experiments/issues/822
+export DD_CELERY_DISTRIBUTED_TRACING=true
+{% endif %}
+
 {% endif -%}
 
 # We want to be able to toggle this on separately from DD in general.