virtcontainers: kata_agent: Factorize appending devices

This commit factorizes the code appending devices to the device list
provided to the Kata agent, in order to reduce the complexity of the
function createContainer().

Fixes #56

Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>

virtcontainers/kata_agent.go

@@ -579,6 +579,25 @@ func constraintGRPCSpec(grpcSpec *grpc.Spec) {
 	}
 }
 
+func (k *kataAgent) appendDevices(deviceList []*grpc.Device, devices []Device) []*grpc.Device {
+	for _, device := range devices {
+		d, ok := device.(*BlockDevice)
+		if !ok {
+			continue
+		}
+
+		kataDevice := &grpc.Device{
+			Type:          kataBlkDevType,
+			VmPath:        d.VirtPath,
+			ContainerPath: d.DeviceInfo.ContainerPath,
+		}
+
+		deviceList = append(deviceList, kataDevice)
+	}
+
+	return deviceList
+}
+
 func (k *kataAgent) createContainer(pod *Pod, c *Container) (*Process, error) {
 	ociSpecJSON, ok := c.config.Annotations[vcAnnotations.ConfigJSONKey]
 	if !ok {
@@ -673,22 +692,8 @@ func (k *kataAgent) createContainer(pod *Pod, c *Container) (*Process, error) {
 	// irrelevant information to the agent.
 	constraintGRPCSpec(grpcSpec)
 
-	// Append container mounts for block devices passed with --device.
-	for _, device := range c.devices {
-		d, ok := device.(*BlockDevice)
-
-		if !ok {
-			continue
-		}
-
-		kataDevice := &grpc.Device{
-			Type:          kataBlkDevType,
-			VmPath:        d.VirtPath,
-			ContainerPath: d.DeviceInfo.ContainerPath,
-		}
-
-		ctrDevices = append(ctrDevices, kataDevice)
-	}
+	// Append container devices for block devices passed with --device.
+	ctrDevices = k.appendDevices(ctrDevices, c.devices)
 
 	req := &grpc.CreateContainerRequest{
 		ContainerId: c.id,

virtcontainers/kata_agent_test.go

@@ -33,7 +33,11 @@ import (
 	"google.golang.org/grpc"
 )
 
-var testKataProxyURLTempl = "unix://%s/kata-proxy-test.sock"
+var (
+	testKataProxyURLTempl   = "unix://%s/kata-proxy-test.sock"
+	testBlockDeviceVirtPath = "testBlockDeviceVirtPath"
+	testBlockDeviceCtrPath  = "testBlockDeviceCtrPath"
+)
 
 func proxyHandlerDiscard(c net.Conn) {
 	buf := make([]byte, 1024)
@@ -336,3 +340,42 @@ func TestGenerateInterfacesAndRoutes(t *testing.T) {
 		"Routes returned didn't match: got %+v, expecting %+v", resRoutes, expectedRoutes)
 
 }
+
+func TestAppendDevicesEmptyContainerDeviceList(t *testing.T) {
+	k := kataAgent{}
+
+	devList := []*pb.Device{}
+	expected := []*pb.Device{}
+	ctrDevices := []Device{}
+
+	updatedDevList := k.appendDevices(devList, ctrDevices)
+	assert.True(t, reflect.DeepEqual(updatedDevList, expected),
+		"Device lists didn't match: got %+v, expecting %+v",
+		updatedDevList, expected)
+}
+
+func TestAppendDevices(t *testing.T) {
+	k := kataAgent{}
+
+	devList := []*pb.Device{}
+	expected := []*pb.Device{
+		{
+			Type:          kataBlkDevType,
+			VmPath:        testBlockDeviceVirtPath,
+			ContainerPath: testBlockDeviceCtrPath,
+		},
+	}
+	ctrDevices := []Device{
+		&BlockDevice{
+			VirtPath: testBlockDeviceVirtPath,
+			DeviceInfo: DeviceInfo{
+				ContainerPath: testBlockDeviceCtrPath,
+			},
+		},
+	}
+
+	updatedDevList := k.appendDevices(devList, ctrDevices)
+	assert.True(t, reflect.DeepEqual(updatedDevList, expected),
+		"Device lists didn't match: got %+v, expecting %+v",
+		updatedDevList, expected)
+}