OpenTelemetry WSGI Instrumentation
This library provides a WSGI middleware that can be used on any WSGI framework (such as Django / Flask / Web.py) to track requests timing through OpenTelemetry.
Usage (Flask)
from flask import Flask
from opentelemetry.instrumentation.wsgi import OpenTelemetryMiddleware
app = Flask(__name__)
app.wsgi_app = OpenTelemetryMiddleware(app.wsgi_app)
@app.route("/")
def hello():
return "Hello!"
if __name__ == "__main__":
app.run(debug=True)
Usage (Django)
Modify the application’s wsgi.py
file as shown below.
import os
from opentelemetry.instrumentation.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)
Usage (Web.py)
import web
from opentelemetry.instrumentation.wsgi import OpenTelemetryMiddleware
from cheroot import wsgi
urls = ('/', 'index')
class index:
def GET(self):
return "Hello, world!"
if __name__ == "__main__":
app = web.application(urls, globals())
func = app.wsgifunc()
func = OpenTelemetryMiddleware(func)
server = wsgi.WSGIServer(
("localhost", 5100), func, server_name="localhost"
)
server.start()
Configuration
Request/Response hooks
This instrumentation supports request and response hooks. These are functions that get called right after a span is created for a request and right before the span is finished for the response.
The client request hook is called with the internal span and an instance of WSGIEnvironment when the method
receive
is called.The client response hook is called with the internal span, the status of the response and a list of key-value (tuples) representing the response headers returned from the response when the method
send
is called.
For example,
from wsgiref.types import WSGIEnvironment, StartResponse
from opentelemetry.instrumentation.wsgi import OpenTelemetryMiddleware
def app(environ: WSGIEnvironment, start_response: StartResponse):
start_response("200 OK", [("Content-Type", "text/plain"), ("Content-Length", "13")])
return [b"Hello, World!"]
def request_hook(span: Span, environ: WSGIEnvironment):
if span and span.is_recording():
span.set_attribute("custom_user_attribute_from_request_hook", "some-value")
def response_hook(span: Span, environ: WSGIEnvironment, status: str, response_headers: list[tuple[str, str]]):
if span and span.is_recording():
span.set_attribute("custom_user_attribute_from_response_hook", "some-value")
OpenTelemetryMiddleware(app, request_hook=request_hook, response_hook=response_hook)
Capture HTTP request and response headers
You can configure the agent to capture specified HTTP headers as span attributes, according to the semantic convention.
Request headers
To capture HTTP request headers as span attributes, set the environment variable
OTEL_INSTRUMENTATION_HTTP_CAPTURE_HEADERS_SERVER_REQUEST
to a comma delimited list of HTTP header names.
For example,
export OTEL_INSTRUMENTATION_HTTP_CAPTURE_HEADERS_SERVER_REQUEST="content-type,custom_request_header"
will extract content-type
and custom_request_header
from the request headers and add them as span attributes.
Request header names in WSGI are case-insensitive and -
characters are replaced by _
. So, giving the header
name as CUStom_Header
in the environment variable will capture the header named custom-header
.
Regular expressions may also be used to match multiple headers that correspond to the given pattern. For example:
export OTEL_INSTRUMENTATION_HTTP_CAPTURE_HEADERS_SERVER_REQUEST="Accept.*,X-.*"
Would match all request headers that start with Accept
and X-
.
To capture all request headers, set OTEL_INSTRUMENTATION_HTTP_CAPTURE_HEADERS_SERVER_REQUEST
to ".*"
.
export OTEL_INSTRUMENTATION_HTTP_CAPTURE_HEADERS_SERVER_REQUEST=".*"
The name of the added span attribute will follow the format http.request.header.<header_name>
where <header_name>
is the normalized HTTP header name (lowercase, with -
replaced by _
). The value of the attribute will be a
single item list containing all the header values.
For example:
http.request.header.custom_request_header = ["<value1>,<value2>"]
Response headers
To capture HTTP response headers as span attributes, set the environment variable
OTEL_INSTRUMENTATION_HTTP_CAPTURE_HEADERS_SERVER_RESPONSE
to a comma delimited list of HTTP header names.
For example,
export OTEL_INSTRUMENTATION_HTTP_CAPTURE_HEADERS_SERVER_RESPONSE="content-type,custom_response_header"
will extract content-type
and custom_response_header
from the response headers and add them as span attributes.
Response header names in WSGI are case-insensitive. So, giving the header name as CUStom-Header
in the environment
variable will capture the header named custom-header
.
Regular expressions may also be used to match multiple headers that correspond to the given pattern. For example:
export OTEL_INSTRUMENTATION_HTTP_CAPTURE_HEADERS_SERVER_RESPONSE="Content.*,X-.*"
Would match all response headers that start with Content
and X-
.
To capture all response headers, set OTEL_INSTRUMENTATION_HTTP_CAPTURE_HEADERS_SERVER_RESPONSE
to ".*"
.
export OTEL_INSTRUMENTATION_HTTP_CAPTURE_HEADERS_SERVER_RESPONSE=".*"
The name of the added span attribute will follow the format http.response.header.<header_name>
where <header_name>
is the normalized HTTP header name (lowercase, with -
replaced by _
). The value of the attribute will be a
single item list containing all the header values.
For example:
http.response.header.custom_response_header = ["<value1>,<value2>"]
Sanitizing headers
In order to prevent storing sensitive data such as personally identifiable information (PII), session keys, passwords,
etc, set the environment variable OTEL_INSTRUMENTATION_HTTP_CAPTURE_HEADERS_SANITIZE_FIELDS
to a comma delimited list of HTTP header names to be sanitized. Regexes may be used, and all header names will be
matched in a case-insensitive manner.
For example,
export OTEL_INSTRUMENTATION_HTTP_CAPTURE_HEADERS_SANITIZE_FIELDS=".*session.*,set-cookie"
will replace the value of headers such as session-id
and set-cookie
with [REDACTED]
in the span.
Note
The environment variable names used to capture HTTP headers are still experimental, and thus are subject to change.
Sanitizing methods
In order to prevent unbound cardinality for HTTP methods by default nonstandard ones are labeled as NONSTANDARD
.
To record all of the names set the environment variable OTEL_PYTHON_INSTRUMENTATION_HTTP_CAPTURE_ALL_METHODS
to a value that evaluates to true, e.g. 1
.
API
- class opentelemetry.instrumentation.wsgi.WSGIGetter[source]
- opentelemetry.instrumentation.wsgi.collect_request_attributes(environ, sem_conv_opt_in_mode=_StabilityMode.DEFAULT)[source]
Collects HTTP request attributes from the PEP3333-conforming WSGI environ and returns a dictionary to be used as span creation attributes.
- opentelemetry.instrumentation.wsgi.collect_custom_request_headers_attributes(environ)[source]
Returns custom HTTP request headers which are configured by the user from the PEP3333-conforming WSGI environ to be used as span creation attributes as described in the specification https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/trace/semantic_conventions/http.md#http-request-and-response-headers
- opentelemetry.instrumentation.wsgi.collect_custom_response_headers_attributes(response_headers)[source]
Returns custom HTTP response headers which are configured by the user from the PEP3333-conforming WSGI environ as described in the specification https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/trace/semantic_conventions/http.md#http-request-and-response-headers
- opentelemetry.instrumentation.wsgi.add_response_attributes(span, start_response_status, response_headers, duration_attrs=None, sem_conv_opt_in_mode=_StabilityMode.DEFAULT)[source]
Adds HTTP response attributes to span using the arguments passed to a PEP3333-conforming start_response callable.
- opentelemetry.instrumentation.wsgi.get_default_span_name(environ)[source]
Default span name is the HTTP method and URL path, or just the method. https://github.com/open-telemetry/opentelemetry-specification/pull/3165 https://opentelemetry.io/docs/reference/specification/trace/semantic_conventions/http/#name
- class opentelemetry.instrumentation.wsgi.OpenTelemetryMiddleware(wsgi, request_hook=None, response_hook=None, tracer_provider=None, meter_provider=None)[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.
- Parameters:
wsgi (
Callable
[[dict
[str
,Any
],StartResponse
],Iterable
[bytes
]]) – The WSGI application callable to forward requests to.request_hook (
Optional
[Callable
[[Span
,dict
[str
,Any
]],None
]]) – Optional callback which is called with the server span and WSGI environ object for every incoming request.response_hook (
Optional
[Callable
[[Span
,dict
[str
,Any
],str
,list
[tuple
[str
,str
]]],None
]]) – Optional callback which is called with the server span, WSGI environ, status_code and response_headers for every incoming request.tracer_provider (
Optional
[TracerProvider
]) – Optional tracer provider to use. If omitted the current globally configured one is used.meter_provider (
Optional
[MeterProvider
]) – Optional meter provider to use. If omitted the current globally configured one is used.