Made changes in netlink code to ignore interface not found error

Author: tamilmani1989

cni/network/network.go

@@ -320,8 +320,8 @@ func (plugin *netPlugin) Delete(args *cniSkel.CmdArgs) error {
 	// Delete the endpoint.
 	err = plugin.nm.DeleteEndpoint(networkId, endpointId)
 	if err != nil {
-		// Log the error but don't return before releasing address
-		log.Printf("Container Namespace might have been removed. Failed to delete endpoint: %v", err)
+		err = plugin.Errorf("Failed to delete endpoint: %v", err)
+		return err
 	}
 
 	// Call into IPAM plugin to release the endpoint's addresses.
@@ -330,7 +330,7 @@ func (plugin *netPlugin) Delete(args *cniSkel.CmdArgs) error {
 		nwCfg.Ipam.Address = address.IP.String()
 		err = plugin.DelegateDel(nwCfg.Ipam.Type, nwCfg)
 		if err != nil {
-			plugin.Errorf("Failed to release address: %v", err)
+			err = plugin.Errorf("Failed to release address: %v", err)
 			return err
 		}
 	}

netlink/link.go

@@ -7,6 +7,7 @@ import (
 	"fmt"
 	"net"
 
+	"github.com/Azure/azure-container-networking/log"
 	"golang.org/x/sys/unix"
 )
 
@@ -146,15 +147,17 @@ func AddLink(link Link) error {
 // DeleteLink deletes a network interface.
 func DeleteLink(name string) error {
 	if name == "" {
-		return fmt.Errorf("Invalid link name")
+		log.Printf("[net] Invalid link name. Not returning error")
+		return nil
 	}
 
-	s, err := getSocket()
+	iface, err := net.InterfaceByName(name)
 	if err != nil {
-		return err
+		log.Printf("[net] Interface not found. Not returning error")
+		return nil
 	}
 
-	iface, err := net.InterfaceByName(name)
+	s, err := getSocket()
 	if err != nil {
 		return err
 	}

network/endpoint.go

@@ -83,7 +83,8 @@ func (nw *network) deleteEndpoint(endpointId string) error {
 	// Look up the endpoint.
 	ep, err := nw.getEndpoint(endpointId)
 	if err != nil {
-		return err
+		log.Printf("[net] Endpoint %v not found. Not Returning error", endpointId)
+		return nil
 	}
 
 	// Call the platform implementation.