OpenTelemetry ASGI Instrumentation

pypi

This library provides a ASGI middleware that can be used on any ASGI framework (such as Django, Starlette, FastAPI or Quart) to track requests timing through OpenTelemetry.

Installation

pip install opentelemetry-instrumentation-asgi

API

The opentelemetry-instrumentation-asgi package provides an ASGI middleware that can be used on any ASGI framework (such as Django-channels / Quart) to track request timing through OpenTelemetry.

Usage (Quart)

from quart import Quart
from opentelemetry.instrumentation.asgi import OpenTelemetryMiddleware

app = Quart(__name__)
app.asgi_app = OpenTelemetryMiddleware(app.asgi_app)

@app.route("/")
async def hello():
    return "Hello!"

if __name__ == "__main__":
    app.run(debug=True)

Usage (Django 3.0)

Modify the application’s asgi.py file as shown below.

import os
from django.core.asgi import get_asgi_application
from opentelemetry.instrumentation.asgi import OpenTelemetryMiddleware

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

application = get_asgi_application()
application = OpenTelemetryMiddleware(application)

Usage (Raw ASGI)

from opentelemetry.instrumentation.asgi import OpenTelemetryMiddleware

app = ...  # An ASGI application.
app = OpenTelemetryMiddleware(app)

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 server request hook is passed a server span and ASGI scope object for every incoming request.

  • The client request hook is called with the internal span and an ASGI scope when the method receive is called.

  • The client response hook is called with the internal span and an ASGI event when the method send is called.

For example,

 def server_request_hook(span: Span, scope: dict):
     if span and span.is_recording():
         span.set_attribute("custom_user_attribute_from_request_hook", "some-value")

 def client_request_hook(span: Span, scope: dict):
     if span and span.is_recording():
         span.set_attribute("custom_user_attribute_from_client_request_hook", "some-value")

 def client_response_hook(span: Span, message: dict):
     if span and span.is_recording():
         span.set_attribute("custom_user_attribute_from_response_hook", "some-value")

OpenTelemetryMiddleware().(application, server_request_hook=server_request_hook, client_request_hook=client_request_hook, client_response_hook=client_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 ASGI 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_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 ASGI 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.

API

class opentelemetry.instrumentation.asgi.ASGIGetter(*args, **kwds)[source]

Bases: opentelemetry.propagators.textmap.Getter[dict]

get(carrier, key)[source]

Getter implementation to retrieve a HTTP header value from the ASGI scope.

Parameters
  • carrier (dict) – ASGI scope object

  • key (str) – header name in scope

Return type

Optional[List[str]]

Returns

A list with a single string with the header value if it exists,

else None.

keys(carrier)[source]

Function that can retrieve all the keys in a carrier object.

Parameters

carrier (dict) – An object which contains values that are used to construct a Context.

Return type

List[str]

Returns

list of keys from the carrier.

class opentelemetry.instrumentation.asgi.ASGISetter(*args, **kwds)[source]

Bases: opentelemetry.propagators.textmap.Setter[dict]

set(carrier, key, value)[source]

Sets response header values on an ASGI scope according to the spec.

Parameters
  • carrier (dict) – ASGI scope object

  • key (str) – response header name to set

  • value (str) – response header value

Return type

None

Returns

None

opentelemetry.instrumentation.asgi.collect_request_attributes(scope)[source]

Collects HTTP request attributes from the ASGI scope and returns a dictionary to be used as span creation attributes.

opentelemetry.instrumentation.asgi.collect_custom_request_headers_attributes(scope)[source]

returns custom HTTP request headers to be added into SERVER span as span attributes Refer specification https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/trace/semantic_conventions/http.md#http-request-and-response-headers

opentelemetry.instrumentation.asgi.collect_custom_response_headers_attributes(message)[source]

returns custom HTTP response headers to be added into SERVER span as span attributes Refer specification https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/trace/semantic_conventions/http.md#http-request-and-response-headers

opentelemetry.instrumentation.asgi.get_host_port_url_tuple(scope)[source]

Returns (host, port, full_url) tuple.

opentelemetry.instrumentation.asgi.set_status_code(span, status_code)[source]

Adds HTTP response attributes to span using the status_code argument.

opentelemetry.instrumentation.asgi.get_default_span_details(scope)[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

Parameters

scope (dict) – the ASGI scope dictionary

Return type

Tuple[str, dict]

Returns

a tuple of the span name, and any attributes to attach to the span.

class opentelemetry.instrumentation.asgi.OpenTelemetryMiddleware(app, excluded_urls=None, default_span_details=None, server_request_hook=None, client_request_hook=None, client_response_hook=None, tracer_provider=None, meter_provider=None, meter=None)[source]

Bases: object

The ASGI application middleware.

This class is an ASGI middleware that starts and annotates spans for any requests it is invoked with.

Parameters
  • app – The ASGI application callable to forward requests to.

  • default_span_details – Callback which should return a string and a tuple, representing the desired default span name and a dictionary with any additional span attributes to set. Optional: Defaults to get_default_span_details.

  • server_request_hook (Optional[Callable[[Span, dict], None]]) – Optional callback which is called with the server span and ASGI scope object for every incoming request.

  • client_request_hook (Optional[Callable[[Span, dict], None]]) – Optional callback which is called with the internal span and an ASGI scope which is sent as a dictionary for when the method receive is called.

  • client_response_hook (Optional[Callable[[Span, dict], None]]) – Optional callback which is called with the internal span and an ASGI event which is sent as a dictionary for when the method send is called.

  • tracer_provider – The optional tracer provider to use. If omitted the current globally configured one is used.