Resilient network free. (#476)

cmd/metal-api/internal/ipam/ipam.go

@@ -2,6 +2,7 @@ package ipam
 
 import (
 	"fmt"
+	"net/netip"
 
 	"github.com/metal-stack/metal-api/cmd/metal-api/internal/metal"
 
@@ -42,13 +43,20 @@ func (i *Ipam) AllocateChildPrefix(parentPrefix metal.Prefix, childLength uint8)
 
 // ReleaseChildPrefix release a child prefix from a parent prefix in the IPAM.
 func (i *Ipam) ReleaseChildPrefix(childPrefix metal.Prefix) error {
-	ipamChildPrefix := i.ip.PrefixFrom(childPrefix.String())
+	_, err := netip.ParsePrefix(childPrefix.String())
+	if err != nil {
+		return fmt.Errorf("invalid child prefix: %w", err)
+	}
 
+	ipamChildPrefix := i.ip.PrefixFrom(childPrefix.String())
 	if ipamChildPrefix == nil {
-		return fmt.Errorf("error finding child prefix in ipam: %s", childPrefix.String())
+		// FIXME: unfortunately, go-ipam does not return a proper error here so we cannot deduce if the prefix
+		// was already deleted or not, so if the database is down or something we continue with network deletion
+		// even though there could be remainings in the go-ipam db
+		return nil
 	}
 
-	err := i.ip.ReleaseChildPrefix(ipamChildPrefix)
+	err = i.ip.ReleaseChildPrefix(ipamChildPrefix)
 	if err != nil {
 		return fmt.Errorf("error releasing child prefix in ipam: %w", err)
 	}

cmd/metal-api/internal/service/network-service.go

@@ -550,21 +550,6 @@ func (r *networkResource) freeNetwork(request *restful.Request, response *restfu
 		return
 	}
 
-	for _, prefix := range nw.Prefixes {
-		usage, err := r.ipamer.PrefixUsage(prefix.String())
-		if err != nil {
-			r.sendError(request, response, defaultError(err))
-			return
-		}
-
-		if usage.UsedIPs > 2 {
-			if err != nil {
-				r.sendError(request, response, defaultError(fmt.Errorf("cannot release child prefix %s because IPs in the prefix are still in use: %v", prefix.String(), usage.UsedIPs-2)))
-				return
-			}
-		}
-	}
-
 	for _, prefix := range nw.Prefixes {
 		err = r.ipamer.ReleaseChildPrefix(prefix)
 		if err != nil {
@@ -767,6 +752,7 @@ func getNetworkUsage(nw *metal.Network, ipamer ipam.IPAMer) *metal.NetworkUsage
 	for _, prefix := range nw.Prefixes {
 		u, err := ipamer.PrefixUsage(prefix.String())
 		if err != nil {
+			// FIXME: the error should not be swallowed here as this can return wrong usage information to the clients
 			continue
 		}
 		usage.AvailableIPs = usage.AvailableIPs + u.AvailableIPs