I followed the setup in below link to enable secure connection to ingress gateway

https://istio.io/docs/tasks/traffic-management/ingress/secure-ingress-sds/

I can send request and get the response from internal service, but is there a way to access certificate common name in internal service?

Internal service is running the following flask application.

from flask import Flask, request
app = Flask(__name__)

@app.route("/first")
def index():
    return str(request.headers)

if __name__ == "__main__":
   app.run(debug=True, host='0.0.0.0')

And it is giving the following output

Accept: */*
X-Forwarded-For: 10.32.0.5
X-Envoy-Decorator-Operation: flasksvc.default.svc.cluster.local:5000/first
X-Request-Id: f5f4d99f-0fe6-450b-a836-f4f228a5908d
X-B3-Traceid: a057039d68a629d516a7e36660197be8
X-Istio-Attributes: Ck8KCnNvdXJjZS51a....
Host: flaskapp.example.com
X-B3-Spanid: 16a7e36660197be8
X-Envoy-Internal: true
User-Agent: curl/7.29.0
Content-Length: 0
X-B3-Sampled: 0
X-Forwarded-Proto: https

I want to see certificate common name in response, could you please help me how to do it with istio 1.4.0 version