feat(oracle): only allow public subnets to be selected from target VCN (canonical#318)

The OCI VCN creation wizard creates both a public and a private subnet
and if the private subnet ends up being the first subnet, then this
would cause all CTF tests using this VCN to hang up and fail because
pycloudlib blindly chooses the first subnet.

Now, private subnets will be skipped/ignored, and the first public
subnet will be selected.

Author: a-dubs

VERSION

@@ -1 +1 @@
-1!5.3.0
+1!5.4.0

pycloudlib/oci/utils.py

@@ -71,6 +71,10 @@ def get_subnet_id(
     subnets = network_client.list_subnets(compartment_id, vcn_id=vcn_id).data
     subnet_id = None
     for subnet in subnets:
+        if subnet.prohibit_internet_ingress:  # skip subnet if it's private
+            print("Ignoring private subnet: " + subnet.id)
+            continue
+        print("Using public subnet: " + subnet.id)
         if subnet.availability_domain == availability_domain:
             subnet_id = subnet.id
             break