OpenTelemetry WSGI Middleware

This library provides a WSGI middleware that can be used on any WSGI framework (such as Django / Flask) to track requests timing through OpenTelemetry.

Usage (Flask)

from flask import Flask
from opentelemetry.ext.wsgi import OpenTelemetryMiddleware

app = Flask(__name__)
app.wsgi_app = OpenTelemetryMiddleware(app.wsgi_app)

def hello():
    return "Hello!"

if __name__ == "__main__":

Usage (Django)

Modify the application’s file as shown below.

import os
from opentelemetry.ext.wsgi import OpenTelemetryMiddleware
from django.core.wsgi import get_wsgi_application

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

application = get_wsgi_application()
application = OpenTelemetryMiddleware(application)


opentelemetry.ext.wsgi.get_header_from_environ(environ, header_name)[source]

Retrieve a HTTP header value from the PEP3333-conforming WSGI environ.

Return type



A list with a single string with the header value if it exists, else an empty list.

opentelemetry.ext.wsgi.setifnotnone(dic, key, value)[source]

Collects HTTP request attributes from the PEP3333-conforming WSGI environ and returns a dictionary to be used as span creation attributes.

opentelemetry.ext.wsgi.add_response_attributes(span, start_response_status, response_headers)[source]

Adds HTTP response attributes to span using the arguments passed to a PEP3333-conforming start_response callable.


Default implementation for name_callback, returns HTTP {METHOD_NAME}.

class opentelemetry.ext.wsgi.OpenTelemetryMiddleware(wsgi, name_callback=<function get_default_span_name>)[source]

Bases: object

The WSGI application middleware.

This class is a PEP 3333 conforming WSGI middleware that starts and annotates spans for any requests it is invoked with.

  • wsgi – The WSGI application callable to forward requests to.

  • name_callback – Callback which calculates a generic span name for an incoming HTTP request based on the PEP3333 WSGI environ. Optional: Defaults to get_default_span_name.