Fix transaction tracing when running Django under ASGI

[jsma]

(Moved from original discussion)

When running Django under ASGI, the middleware that Elastic APM injects is not tracking standard Django request transactions.

Here's my asgi.py:

django_asgi_app = get_asgi_application()

application = ProtocolTypeRouter(
    {
        "http": django_asgi_app,
    }
)

My settings.ELASTIC_APM:

{'SERVICE_NAME': 'myapp',
 'SERVER_URL': 'http://fleet-server:8200',
 'SECRET_TOKEN': '*************',
 'ENVIRONMENT': 'development',
 'DEBUG': True}

I've browsed several pages and waited for Fleet to flush but all I see are Celery tasks:

Nothing is logged as a request transaction type by the standard Django middleware when running under Daphne.

If I switch the project back to standard WSGI/Django runserver, it logs request transactions:

[MWedl]

We encountered this bug after updating to Django 5.0. We also run django in ASGI mode. In Django 4.x, transaction tracing worked fine, even in ASGI mode.

[benclark158]

I have encountered this as well in Django 5.0. When I call the following within my view class

import elasticapm
elasticapm.label(obj_id='id')

I get this message: Ignored labels obj_id. No transaction currently active. But when I downgrade to django 4.2.13 it works as expected

[xrmx]

Created a new django 5.0.6 project.

Added in settings.py:

ELASTIC_APM = {
    "SERVICE_NAME": "djangoasgi",
    "SERVER_URL": "",
    "API_KEY": "",
    "DEBUG": True,
}

INSTALLED_APPS = [
    'django.contrib.admin',
    'django.contrib.auth',
    'django.contrib.contenttypes',
    'django.contrib.sessions',
    'django.contrib.messages',
    'django.contrib.staticfiles',
    'elasticapm.contrib.django',
]

Added in views:

from django.http import HttpResponse
import elasticapm


async def hello(request):
    elasticapm.set_transaction_name("djangoasgi.hello")
    elasticapm.label(is_asgi=True)
    return HttpResponse("Hello")

In urls.py:

from django.contrib import admin
from django.urls import path
from . import views

urlpatterns = [
    path('admin/', admin.site.urls),
    path('hello', views.hello),
]

in asgi.py:

import os

from django.core.asgi import get_asgi_application

os.environ.setdefault('DJANGO_SETTINGS_MODULE', 'djangoasgi.settings')

from elasticapm.contrib.asgi import ASGITracingMiddleware

application = ASGITracingMiddleware(get_asgi_application())

run it via gunicorn djangoasgi.asgi:application -w 1 -k uvicorn.workers.UvicornWorker

And got

[benclark158]

Thank you @xrmx doing that and extending your code fixed the issues I was having. I adapted your solution to use a custom middleware as I had a lot of URLs to monitor.

I have found that the config option TRANSACTION_IGNORE_URLS didn't work with your solution though. I did some customisation to get it working with the middleware and ASGI middleware:

middleware.py

import elasticapm
from elasticapm.contrib.django.middleware import TracingMiddleware

class CustomTracingMiddleware(TracingMiddleware):

    def process_request(self, request: HttpRequest):
        
        if elasticapm.get_transaction_id():
            transaction_name: str = "{} {}".format(request.method.upper(), request.path.lower()) #type: ignore
            elasticapm.set_transaction_name(transaction_name) #type: ignore

        return None

asgi.py

from elasticapm.contrib.asgi import ASGITracingMiddleware

class CustomASGITracingMiddleware(ASGITracingMiddleware):
    def get_url(self, scope, host: str | None = None) -> Tuple[str, dict[str, str]]:
        _, url_dict = super().get_url(scope, host)
        path = scope.get("root_path", "") + scope.get("path", "")
        return path, url_dict

application = CustomASGITracingMiddleware(get_asgi_application())

settings.py

MIDDLEWARE = [
    'ehs_api.middleware.CustomTracingMiddleware',
    # add others here
]

ELASTIC_APM = {
    'SERVICE_NAME': 'djangoapm',
    'SERVER_URL': '',
    'DEBUG': True, #allows it to run in test mode
    'TRANSACTION_IGNORE_URLS': [
        '/__debug__/*',
    ],
    'DJANGO_TRANSACTION_NAME_FROM_ROUTE': True,
    'DJANGO_AUTOINSERT_MIDDLEWARE': False
}