Thank you for your quick reply and your estimates.
I was not aware that I could use the x-google-endpoint OpenAPI extensions
, it is not specified in the Api Gateway documentation, only in cloud endpoints. Actually, it would be acceptable for us to have this feature. How I understand this is that it is supposed to let through all the preflight OPTIONS requests matching the endpoints defined in the openapi spec right ? I tried to set it up on my api gateway but without any success... The options methods are still inaccessible :
My Gateway config :
Maybe I got the feature wrong ? Or maybe it works only on Cloud Endpoints ?
The only solution at this point would be to define all the OPTIONS methods in the openapi spec file but it seems wrong.