def configure_opentelemetry(flask_app: flask.Flask):
"""Configure a flask application to use OpenTelemetry.
This activates the specific components:
* sets tracer to the SDK's Tracer
* enables requests integration on the Tracer
* uses a WSGI middleware to enable configuration
TODO:
* processors?
* exporters?
"""
# Start by configuring all objects required to ensure
# a complete end to end workflow.
# the preferred implementation of these objects must be set,
# as the opentelemetry-api defines the interface with a no-op
# implementation.
trace.set_preferred_tracer_implementation(lambda _: Tracer())
# Next, we need to configure how the values that are used by
# traces and metrics are propagated (such as what specific headers
# carry this value).
# TBD: can remove once default TraceContext propagators are installed.
propagators.set_global_httptextformat(B3Format())
# Integrations are the glue that binds the OpenTelemetry API
# and the frameworks and libraries that are used together, automatically
# creating Spans and propagating context as appropriate.
opentelemetry.ext.http_requests.enable(trace.tracer())
instrument_app(flask_app)
def test_try_set_again(self):
self.assertTrue(trace.tracer())
# Try setting after the tracer has already been created:
with self.assertRaises(RuntimeError) as einfo:
trace.set_preferred_tracer_implementation(
get_opentelemetry_implementation)
self.assertIn("already loaded", str(einfo.exception))
def setUpClass(cls):
"""Set preferred tracer implementation only once rather than before
every test method.
"""
trace.set_preferred_tracer_implementation(lambda T: Tracer())
# Save current propagator to be restored on teardown.
cls._previous_propagator = propagators.get_global_httptextformat()
# Set mock propagator for testing.
propagators.set_global_httptextformat(MockHTTPTextFormat)
from flask import Flask, request, render_template from opentelemetry import trace, propagators from opentelemetry.sdk.trace import Tracer from opentelemetry.sdk.context.propagation.b3_format import B3Format from opentelemetry.ext.http_requests import enable from opentelemetry.ext.wsgi import OpenTelemetryMiddleware from opentelemetry.sdk.trace.export import ConsoleSpanExporter from opentelemetry.sdk.trace.export import SimpleExportSpanProcessor from kitchen_service import KitchenService from kitchen_consumer import KitchenConsumer from donut import Donut from status import NEW_ORDER trace.set_preferred_tracer_implementation(lambda T: Tracer()) propagators.set_global_httptextformat(B3Format()) tracer = trace.tracer() enable(tracer) tracer.add_span_processor(SimpleExportSpanProcessor(ConsoleSpanExporter())) app = Flask(__name__) app.static_folder = 'static' app.wsgi_app = OpenTelemetryMiddleware(app.wsgi_app) kitchen_service = KitchenService() kitchen_consumer = KitchenConsumer()
def test_preferred_impl(self):
trace.set_preferred_tracer_implementation(
get_opentelemetry_implementation)
tracer = trace.tracer()
self.assertIs(tracer, DUMMY_TRACER)
def tracer():
trace.set_preferred_tracer_implementation(lambda T: Tracer())
return trace.tracer()
def setUpClass(cls):
"""Set preferred tracer implementation only once rather than before
every test method.
"""
trace.set_preferred_tracer_implementation(lambda T: Tracer())
