Force to invoke all CNI plugin's delete at pods' tearing down

In case of multiple interfaces in pod, when the pod is deleted,
forEachnetwork() is called with multiple network attachments.
If forEachnetwork() causes the error at the middle of processing networks,
then forEachnetwork() just returns and following network is not processed.
From CNI runtime point of view, all CNI plugin should be invoked to delete
interfaces.

This change introduce 'force' option in forEachnetwork() and try to
continue to process (i.e. delete network) even though forEachnetwork()
causes the error.

pkg/ocicni/ocicni.go

@@ -444,7 +444,7 @@ func (plugin *cniNetworkPlugin) loadNetworkFromCache(name string, rt *libcni.Run
 
 type forEachNetworkFn func(*cniNetwork, *PodNetwork, *libcni.RuntimeConf) error
 
-func (plugin *cniNetworkPlugin) forEachNetwork(podNetwork *PodNetwork, fromCache bool, actionFn forEachNetworkFn) error {
+func (plugin *cniNetworkPlugin) forEachNetwork(podNetwork *PodNetwork, fromCache bool, actionFn forEachNetworkFn, force bool) error {
 	networks := podNetwork.Networks
 	if len(networks) == 0 {
 		networks = append(networks, NetAttachment{
@@ -457,6 +457,9 @@ func (plugin *cniNetworkPlugin) forEachNetwork(podNetwork *PodNetwork, fromCache
 		if req.Ifname != "" {
 			// Make sure the requested name isn't already assigned
 			if allIfNames[req.Ifname] {
+				if force {
+					continue
+				}
 				return fmt.Errorf("network %q requested interface name %q already assigned", req.Name, req.Ifname)
 			}
 			allIfNames[req.Ifname] = true
@@ -482,6 +485,9 @@ func (plugin *cniNetworkPlugin) forEachNetwork(podNetwork *PodNetwork, fromCache
 		rt, err := buildCNIRuntimeConf(podNetwork, ifName, podNetwork.RuntimeConfig[network.Name])
 		if err != nil {
 			logrus.Errorf("error building CNI runtime config: %v", err)
+			if force {
+				continue
+			}
 			return err
 		}
 
@@ -503,16 +509,25 @@ func (plugin *cniNetworkPlugin) forEachNetwork(podNetwork *PodNetwork, fromCache
 				// try to load the networks again
 				if err2 := plugin.syncNetworkConfig(); err2 != nil {
 					logrus.Error(err2)
+					if force {
+						continue
+					}
 					return err
 				}
 				cniNet, err = plugin.getNetwork(network.Name)
 				if err != nil {
+					if force {
+						continue
+					}
 					return err
 				}
 			}
 		}
 
 		if err := actionFn(cniNet, podNetwork, rt); err != nil {
+			if force {
+				continue
+			}
 			return err
 		}
 	}
@@ -552,7 +567,7 @@ func (plugin *cniNetworkPlugin) SetUpPodWithContext(ctx context.Context, podNetw
 			},
 		})
 		return nil
-	}); err != nil {
+	}, false); err != nil {
 		return nil, err
 	}
 
@@ -658,7 +673,7 @@ func (plugin *cniNetworkPlugin) TearDownPodWithContext(ctx context.Context, podN
 			return fmt.Errorf("Error while removing pod from CNI network %q: %s", network.name, err)
 		}
 		return nil
-	})
+	}, true)
 }
 
 // GetPodNetworkStatus returns IP addressing and interface details for all
@@ -695,7 +710,7 @@ func (plugin *cniNetworkPlugin) GetPodNetworkStatusWithContext(ctx context.Conte
 			})
 		}
 		return nil
-	}); err != nil {
+	}, false); err != nil {
 		return nil, err
 	}
 
@@ -810,7 +825,7 @@ func buildCNIRuntimeConf(podNetwork *PodNetwork, ifName string, runtimeConfig Ru
 	}
 
 	// Propagate existing CNI_ARGS to non-k8s consumers
-	for _, kvpairs := range strings.Split(os.Getenv("CNI_ARGS"), ";"){
+	for _, kvpairs := range strings.Split(os.Getenv("CNI_ARGS"), ";") {
 		if keyval := strings.SplitN(kvpairs, "=", 2); len(keyval) == 2 {
 			rt.Args = append(rt.Args, [2]string{keyval[0], keyval[1]})
 		}