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Please provide as much information as possible. At least, this should include a description of your issue and steps to reproduce the problem. If possible please provide a summary of what steps or workarounds you have already tried, and any docs or articles you found (un)helpful.

I have a two services running in GCP app engine; let's say service A and B, and then I deployed a spring cloud gateway service to route external traffic to these two services based on path predicates. service A and B are deployed in app engine flexible. initially I had the gateway deployed in app engine flexible and it was working perfectly well. because we have some batch services which has response time of more than 10 mins (app engine standard has max-response-timeout of 10 mins), we had to decide to migrate the gateway to app engine flexible.

The service gets deployed correctly, the actuator endpoints works perfectly, I call /actuator/gateway/routes end point and the routing config looks good.

Problem you have encountered:
The problem is that when the gateway redirects the request to the service A or B, the service return a 302 to the gateway's URL and the browser goes in to a redirect loop. The issue is not seen when I deploy the gateway in app engine standard.


Steps to reproduce:
Deploy the spring cloud gateway in app engine flexible, and deploy any other service in another app engine flexible. When requests are routed from gateway to the downstream api, the downstream api return 302 redirect.


Other information (workarounds you have tried, documentation consulted, etc):
I ran the downstream API in my local and tunneled the port to internet using a ngrok, Deployed the gateway with the roure URI as the tunneled URI. Now when I send the request to the gateway, the gateway routes in to the service running in my local, implying that the issue is with request from one app engine flex to another.