instrumentation-special-cases.md

The official Splunk documentation for this page is Additional instructions for Python frameworks. For instructions on how to contribute to the docs, see CONTRIBUTING.md.

Instrumentation Special Cases

Django

Automatically instrumenting Django requires DJANGO_SETTINGS_MODULE environment variable to be set. The value should be the same as set in your manage.py or wsgi.py modules. For example, if your manage.py file sets this environment variable to mydjangoproject.settings and you start your Django project as ./manage.py runserver, then you can automatically instrument your Django project as follows:

export DJANGO_SETTINGS_MODULE=mydjangoproject.settings
splunk-py-trace ./manage.py runserver

uWSGI

When using uWSGI, tracing must be setup as a response to the post_fork signal.

For example:

import uwsgidecorators
from splunk_otel.tracing import start_tracing

@uwsgidecorators.postfork
def setup_tracing():
    start_tracing()

Running with uwsgi

uwsgi --http :9090 --wsgi-file <your_app.py> --callable <your_wsgi_callable> --master --enable-threads

The above snippet should be placed in the main python script that uwsgi imports and loads.

UWSGI and Flask

Using USWGI with Flask requires one additional little step. Calling start_tracing() does not auto-instrument pre-existing flask app instances but only flask instances created after. When running flask with uwsgi, we need to create a new flask app instance before the post_fork signal is emitted. This means your flask app will not be auto-instrumented. However, you can still auto-instrument an existing flask app explicitly by importing and calling the flask instrumentor.

For example:

# app.py
import uwsgidecorators
from splunk_otel.tracing import start_tracing
from opentelemetry.instrumentation.flask import FlaskInstrumentor
from flask import Flask

app = Flask(__name__)

@uwsgidecorators.postfork
def setup_tracing():
    start_tracing()
    # instrument our flask app instance eplicitly
    FlaskInstrumentor().instrument_app(app)

@app.route('/')
def hello_world():
    return 'Hello, World!'

Running with uWSGI:

uwsgi --http :9090 --wsgi-file app.py --callable app --master --enable-threads