Add handling for disk IDs with prefix

Some IaaS provider have disk ID with prefix which is separated
by a hyphen character. However the symlink doesn't have the prefix
and the hyphen character that is why the resolution doesn't work in this
case. This pr removes the prefix with the hyphen from the disk ID before
the resolution to provide a solution for this case

infrastructure/devicepathresolver/id_device_path_resolver.go

@@ -3,6 +3,7 @@ package devicepathresolver
 import (
 	"fmt"
 	"path"
+	"strings"
 	"time"
 
 	boshudev "github.com/cloudfoundry/bosh-agent/platform/udevdevice"
@@ -51,9 +52,17 @@ func (idpr idDevicePathResolver) GetRealDevicePath(diskSettings boshsettings.Dis
 	stopAfter := time.Now().Add(idpr.diskWaitTimeout)
 	found := false
 
-	var realPath string
+	var realPath, diskID string
+
+	dashIndex := strings.IndexRune(diskSettings.ID, '-')
+	if dashIndex != -1 {
+		//some disks are mounted without the dash or without the prefix,
+		//we remove it here entirely so the Glob by-id works for all scenarios
+		diskID = diskSettings.ID[dashIndex+1:]
+	} else {
+		diskID = diskSettings.ID
+	}
 
-	diskID := diskSettings.ID
 	deviceGlobPattern := fmt.Sprintf("*%s", diskID)
 	deviceIDPathGlobPattern := path.Join("/", "dev", "disk", "by-id", deviceGlobPattern)
 

infrastructure/devicepathresolver/id_device_path_resolver_test.go

@@ -28,7 +28,7 @@ var _ = Describe("IDDevicePathResolver", func() {
 		udev = fakeudev.NewFakeUdevDevice()
 		fs = fakesys.NewFakeFileSystem()
 		diskSettings = boshsettings.DiskSettings{
-			ID: "fake-disk-id-include-longname",
+			ID: "some-fake-disk-id-include-longname",
 		}
 	})
 
@@ -54,21 +54,46 @@ var _ = Describe("IDDevicePathResolver", func() {
 				err = fs.Symlink("/dev/fake-device-path", "/dev/intermediate/fake-device-path")
 				Expect(err).ToNot(HaveOccurred())
 
-				err = fs.Symlink("/dev/intermediate/fake-device-path", "/dev/disk/by-id/virtio-fake-disk-id-include-longname")
+				err = fs.Symlink("/dev/intermediate/fake-device-path", "/dev/disk/by-id/virtio-fake_disk_id_include_longname")
 				Expect(err).ToNot(HaveOccurred())
 
-				fs.SetGlob("/dev/disk/by-id/*fake-disk-id-include-longname", []string{"/dev/disk/by-id/virtio-fake-disk-id-include-longname"})
+				fs.SetGlob("/dev/disk/by-id/*fake_disk_id_include_longname", []string{"/dev/disk/by-id/virtio-fake_disk_id_include_longname"})
 			})
 
-			It("returns fully resolved the path (not potentially relative symlink target)", func() {
-				path, timeout, err := pathResolver.GetRealDevicePath(diskSettings)
-				Expect(err).ToNot(HaveOccurred())
+			Context("and disk id has a prefix separated by hyphen", func() {
+				BeforeEach(func() {
+					diskSettings = boshsettings.DiskSettings{
+						ID: "some-fake_disk_id_include_longname",
+					}
+				})
+				It("returns fully resolved the path (not potentially relative symlink target)", func() {
+					path, timeout, err := pathResolver.GetRealDevicePath(diskSettings)
+					Expect(err).ToNot(HaveOccurred())
 
-				devicePath, err := filepath.Abs("/dev/fake-device-path")
-				Expect(err).ToNot(HaveOccurred())
+					devicePath, err := filepath.Abs("/dev/fake-device-path")
+					Expect(err).ToNot(HaveOccurred())
 
-				Expect(path).To(Equal(devicePath))
-				Expect(timeout).To(BeFalse())
+					Expect(path).To(Equal(devicePath))
+					Expect(timeout).To(BeFalse())
+				})
+			})
+
+			Context("and disk id has no prefix", func() {
+				BeforeEach(func() {
+					diskSettings = boshsettings.DiskSettings{
+						ID: "fake_disk_id_include_longname",
+					}
+				})
+				It("returns fully resolved the path (not potentially relative symlink target)", func() {
+					path, timeout, err := pathResolver.GetRealDevicePath(diskSettings)
+					Expect(err).ToNot(HaveOccurred())
+
+					devicePath, err := filepath.Abs("/dev/fake-device-path")
+					Expect(err).ToNot(HaveOccurred())
+
+					Expect(path).To(Equal(devicePath))
+					Expect(timeout).To(BeFalse())
+				})
 			})
 		})