OpenTelemetry Flask Instrumentation

import os
from flask import Flask
from opentelemetry import trace
from opentelemetry.sdk.resources import Resource
from opentelemetry.sdk.trace import TracerProvider
from opentelemetry.sdk.trace.export import BatchSpanProcessor
from opentelemetry.exporter.otlp.proto.http.trace_exporter import OTLPSpanExporter
from opentelemetry.instrumentation.flask import FlaskInstrumentor

# Configure OpenTelemetry SDK
# Ensure these environment variables are set for your OTLP collector
otlp_endpoint = os.environ.get('OTEL_EXPORTER_OTLP_ENDPOINT', 'http://localhost:4318/v1/traces')
service_name = os.environ.get('OTEL_SERVICE_NAME', 'my-flask-app')

resource = Resource.create({
    "service.name": service_name,
    "service.version": "1.0.0"
})

provider = TracerProvider(resource=resource)
processor = BatchSpanProcessor(OTLPSpanExporter(endpoint=otlp_endpoint))
provider.add_span_processor(processor)
trace.set_tracer_provider(provider)

app = Flask(__name__)

# Instrument the Flask application
FlaskInstrumentor().instrument_app(app)

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

@app.route("/data")
def get_data():
    # Example of manual span within an instrumented route
    with trace.get_current_span().tracer.start_as_current_span("get-data-logic"):
        return {"value": 123}

if __name__ == "__main__":
    # IMPORTANT: Do not run with debug=True in production or with auto-instrumentation
    # due to Flask reloader issues with OpenTelemetry. For development, use
    # `flask run --no-debugger --no-reloader` or set `debug=False` for basic testing.
    print(f"Flask app running on http://127.0.0.1:5000 with OTLP exporter to {otlp_endpoint}")
    app.run(host="0.0.0.0", port=5000, debug=False)