Use Cf-Connecting-Ip as remote IP

app.py

@@ -25,8 +25,12 @@ def tunnel():
     try:
         logging.debug(f"Request headers: {request.headers}")
         logging.debug(f"Remote addr: {request.remote_addr}")
-        logging.debug(f"Request forwarded for: {request.headers.getlist('X-Forwarded-For')}")
-        remote_addr = request.headers.getlist("X-Forwarded-For")[0] if request.headers.getlist("X-Forwarded-For") else request.remote_addr
+        if request.headers.getlist("Cf-Connecting-Ip"):
+            remote_addr = request.headers.getlist("Cf-Connecting-Ip")[0]
+        elif request.headers.getlist("X-Forwarded-For"):
+            remote_addr = request.headers.getlist("X-Forwarded-For")[0] 
+        else:
+            remote_addr = request.remote_addr
 
         envelope = flask.request.data
         piece = envelope.split(b"\n")[0].decode("utf-8")
@@ -43,7 +47,7 @@ def tunnel():
         url = f"https://{dsn.hostname}/api/{project_id}/envelope/"
         headers = {
             "Content-Type": "application/x-sentry-envelope",
-            "X-Forwarded-For": request.remote_addr,
+            "X-Forwarded-For": remote_addr,
         }
         logging.debug(f"Forwarding envelope to {dsn.hostname} for project {project_id}. {url=} {headers=}")