Improve GetSriovNicIPs error message

In case of error, it is useful to know the reason why it
was not possible to get the IP address of SR-IOV interface.

Add description to each returned error and return an error
in case the requested interface is not found.

Add "github.com/stretchr/testify/assert" dependency adn
unit tests for GetSriovNicIPs

Signed-off-by: Andrea Panattoni <[email protected]>

go.mod

@@ -21,6 +21,7 @@ require (
 	github.com/openshift/machine-config-operator v0.0.1-0.20201023110058-6c8bd9b2915c
 	github.com/pkg/errors v0.9.1
 	github.com/spf13/cobra v1.1.1
+	github.com/stretchr/testify v1.6.1
 	github.com/vishvananda/netlink v1.1.0
 	github.com/vishvananda/netns v0.0.0-20191106174202-0a2b9b5464df
 	golang.org/x/time v0.0.0-20210220033141-f8bda1e9f3ba
@@ -103,6 +104,7 @@ require (
 	github.com/modern-go/reflect2 v1.0.1 // indirect
 	github.com/nxadm/tail v1.4.4 // indirect
 	github.com/peterbourgon/diskv v2.0.1+incompatible // indirect
+	github.com/pmezard/go-difflib v1.0.0 // indirect
 	github.com/prometheus/client_golang v1.7.1 // indirect
 	github.com/prometheus/client_model v0.2.0 // indirect
 	github.com/prometheus/common v0.10.0 // indirect

test/util/network/network.go

@@ -98,18 +98,25 @@ func GetNicsByPrefix(pod *k8sv1.Pod, ifcPrefix string) ([]string, error) {
 // GetSriovNicIPs returns the list of ip addresses related to the given
 // interface name for the given pod.
 func GetSriovNicIPs(pod *k8sv1.Pod, ifcName string) ([]string, error) {
+
+	networksStatus, ok := pod.ObjectMeta.Annotations["k8s.v1.cni.cncf.io/networks-status"]
+	if !ok {
+		return nil, fmt.Errorf("pod [%s] has no annotation `k8s.v1.cni.cncf.io/networks-status`", pod.Name)
+	}
+
 	var nets []Network
-	err := json.Unmarshal([]byte(pod.ObjectMeta.Annotations["k8s.v1.cni.cncf.io/networks-status"]), &nets)
+	err := json.Unmarshal([]byte(networksStatus), &nets)
 	if err != nil {
-		return nil, err
+		return nil, fmt.Errorf("can't unmarshal annotation `k8s.v1.cni.cncf.io/networks-status`: %w", err)
 	}
 	for _, net := range nets {
 		if net.Interface != ifcName {
 			continue
 		}
 		return net.Ips, nil
 	}
-	return nil, nil
+
+	return nil, fmt.Errorf("interface [%s] not found in pod annotation", ifcName)
 }
 
 // Return a definition of a macvlan NetworkAttachmentDefinition

test/util/network/network_test.go

@@ -0,0 +1,76 @@
+package network
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+
+	k8sv1 "k8s.io/api/core/v1"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+)
+
+func TestGetSriovNicIPs(t *testing.T) {
+	networksStatus := `[{
+		"name": "network1",
+		    "interface": "eth0",
+		"ips": [
+			"10.132.2.200"
+		],
+		"mac": "0a:58:0a:84:02:c8",
+		"default": true,
+		"dns": {}
+	},{
+		"name": "sriov-conformance-testing/test-multi-networkpolicy-sriov-network",
+		"interface": "net1",
+		"ips": [
+			"2.2.2.49"
+		],
+		"mac": "96:a2:09:fb:4d:c3",
+		"dns": {},
+		"device-info": {
+			"type": "pci",
+			"version": "1.0.0",
+			"pci": {
+				"pci-address": "0000:19:00.4"
+			}
+		}
+	}]`
+
+	p := &k8sv1.Pod{
+		ObjectMeta: metav1.ObjectMeta{
+			Annotations: map[string]string{
+				"k8s.v1.cni.cncf.io/networks-status": networksStatus,
+			},
+		},
+	}
+
+	ips, err := GetSriovNicIPs(p, "eth0")
+	assert.NoError(t, err)
+	assert.Contains(t, ips, "10.132.2.200")
+
+	ips, err = GetSriovNicIPs(p, "net1")
+	assert.NoError(t, err)
+	assert.Contains(t, ips, "2.2.2.49")
+
+	_, err = GetSriovNicIPs(p, "eth999")
+	assert.Error(t, err)
+	assert.Contains(t, err.Error(), "interface [eth999] not found")
+}
+
+func TestGetSriovNicIPsErrors(t *testing.T) {
+	p := &k8sv1.Pod{}
+	_, err := GetSriovNicIPs(p, "eth0")
+	assert.Error(t, err)
+	assert.Contains(t, err.Error(), "has no annotation `k8s.v1.cni.cncf.io/networks-status`")
+
+	p = &k8sv1.Pod{
+		ObjectMeta: metav1.ObjectMeta{
+			Annotations: map[string]string{
+				"k8s.v1.cni.cncf.io/networks-status": "xxx",
+			},
+		},
+	}
+	_, err = GetSriovNicIPs(p, "eth0")
+	assert.Error(t, err)
+	assert.Contains(t, err.Error(), "invalid character")
+}