OpenTelemetry Starlette Instrumentation

pypi

This library provides automatic and manual instrumentation of Starlette web frameworks, instrumenting http requests served by applications utilizing the framework.

auto-instrumentation using the opentelemetry-instrumentation package is also supported.

Installation

pip install opentelemetry-instrumentation-starlette

API

Usage

from opentelemetry.instrumentation.starlette import StarletteInstrumentor
from starlette import applications
from starlette.responses import PlainTextResponse
from starlette.routing import Route

def home(request):
    return PlainTextResponse("hi")

app = applications.Starlette(
    routes=[Route("/foobar", home)]
)
StarletteInstrumentor.instrument_app(app)

Configuration

Exclude lists

To exclude certain URLs from being tracked, set the environment variable OTEL_PYTHON_STARLETTE_EXCLUDED_URLS (or OTEL_PYTHON_EXCLUDED_URLS as fallback) with comma delimited regexes representing which URLs to exclude.

For example,

export OTEL_PYTHON_STARLETTE_EXCLUDED_URLS="client/.*/info,healthcheck"

will exclude requests such as https://site/client/123/info and https://site/xyz/healthcheck.

Request/Response hooks

Utilize request/response hooks to execute custom logic to be performed before/after performing a request. The server request hook takes in 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 which is sent as a dictionary for when the method recieve is called. The client response hook is called with the internal span and an ASGI event which is sent as a dictionary for when the method send is called.

 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")

StarletteInstrumentor().instrument(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 predefined HTTP headers as span attributes, according to the semantic convention.

Request headers

To capture predefined HTTP request headers as span attributes, set the environment variable OTEL_INSTRUMENTATION_HTTP_CAPTURE_HEADERS_SERVER_REQUEST to a comma-separated 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 request headers and add them as span attributes.

It is recommended that you should give the correct names of the headers to be captured in the environment variable. Request header names in starlette are case insensitive. So, giving header name as CUStom-Header in environment variable will be able capture header with name custom-header.

The name of the added span attribute will follow the format http.request.header.<header_name> where <header_name> being the normalized HTTP header name (lowercase, with - characters replaced by _ ). The value of the attribute will be single item list containing all the header values.

Example of the added span attribute, http.request.header.custom_request_header = ["<value1>,<value2>"]

Response headers

To capture predefined HTTP response headers as span attributes, set the environment variable OTEL_INSTRUMENTATION_HTTP_CAPTURE_HEADERS_SERVER_RESPONSE to a comma-separated 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 response headers and add them as span attributes.

It is recommended that you should give the correct names of the headers to be captured in the environment variable. Response header names captured in starlette are case insensitive. So, giving header name as CUStomHeader in environment variable will be able capture header with name customheader.

The name of the added span attribute will follow the format http.response.header.<header_name> where <header_name> being the normalized HTTP header name (lowercase, with - characters replaced by _ ). The value of the attribute will be single item list containing all the header values.

Example of the added span attribute, http.response.header.custom_response_header = ["<value1>,<value2>"]

Note

Environment variable names to capture http headers are still experimental, and thus are subject to change.

API

class opentelemetry.instrumentation.starlette.StarletteInstrumentor(*args, **kwargs)[source]

Bases: opentelemetry.instrumentation.instrumentor.BaseInstrumentor

An instrumentor for starlette

See BaseInstrumentor

static instrument_app(app, server_request_hook=None, client_request_hook=None, client_response_hook=None, tracer_provider=None)[source]

Instrument an uninstrumented Starlette application.

instrumentation_dependencies()[source]

Return a list of python packages with versions that the will be instrumented.

The format should be the same as used in requirements.txt or setup.py.

For example, if an instrumentation instruments requests 1.x, this method should look like:

def instrumentation_dependencies(self) -> Collection[str]:

return [‘requests ~= 1.0’]

This will ensure that the instrumentation will only be used when the specified library is present in the environment.

Return type

Collection[str]