I have jobs and APIs hosted on cloud composer and App Engine that works fine. However for one of my job I would need to call an API that is IP restricted.
As far as I understand, I see that there's no way to have a fixed IP for app engine and cloud composer workers and I don't know what is the best solution then.
I thought about creating a GCE with a fixed IP that would be switched on/off by the cloud composer or app engine and then the API call would be executed by the startup-script. However, it restrains this to only asynchronous tasks and it seems to add a non desired step.
I have been told that it is possible to set up a proxy but I don't know how to do it and I did not find comprehensive docs about it.
Would you have advice for this use-case ?
Thanks a lot for your help
As you have mentioned: you can set up a TCP or UDP proxy in GCE as a relay, and then send requests to the relay (which then forwards those requests to the IP-restricted host).
However, that might be somewhat brittle in some cases (and introduces a single point of failure). Therefore, another option you could consider is creating a private IP Cloud Composer environment, and then using Cloud NAT for public IP connectivity. That way, all requests from Airflow within Composer will look like they are originating from the IP address of the NAT gateway.
It's probably out of scope to you, but you could whitelist the whole range of app engine ip by performing a lookup on _cloud-netblocks.googleusercontent.com
In this case you are whitelisting any app engine applications, so be sure this api has another kind of authorization and good security. More info on the App Engine KB.
What I would do is install or implement some kind of API proxy on GCE. It's a bummer to have a VM on 24/7 for this kind of task so you could also use an autoscaler to scale to 0 (not sure about this one).