Tests: Clean up any old devmapper leftovers before starting tests

devmapper/devmapper.go

@@ -347,3 +347,20 @@ func UdevWait(cookie uint32) error {
 func LogInitVerbose(level int) {
 	C.dm_log_init_verbose(C.int(level))
 }
+
+// Useful helper for cleanup
+func RemoveDevice(name string) error {
+	task := TaskCreate(DeviceRemove)
+	if task == nil {
+		return fmt.Errorf("Can't create task of type DeviceRemove")
+	}
+	err := task.SetName(name)
+	if err != nil {
+		return fmt.Errorf("Can't set task name %s", name)
+	}
+	err = task.Run()
+	if err != nil {
+		return fmt.Errorf("Error running removeDevice")
+	}
+	return nil
+}

runtime_test.go

@@ -6,6 +6,7 @@ import (
 	"github.com/dotcloud/docker/utils"
 	"github.com/dotcloud/docker/devmapper"
 	"io"
+	"io/ioutil"
 	"log"
 	"net"
 	"os"
@@ -84,6 +85,32 @@ func layerArchive(tarfile string) (io.Reader, error) {
 	return f, nil
 }
 
+// Remove any leftover device mapper devices from earlier runs of the unit tests
+func cleanupDevMapper() {
+	infos, _ := ioutil.ReadDir("/dev/mapper")
+	if infos != nil {
+		hasPool := false
+		for _, info := range infos {
+			name := info.Name()
+			if strings.HasPrefix(name, "docker-unit-tests-devices-") {
+				if name == "docker-unit-tests-devices-pool" {
+					hasPool = true
+				} else {
+					if err := devmapper.RemoveDevice(name); err != nil {
+						panic(fmt.Errorf("Unable to remove existing device %s: %s", name, err))
+					}
+				}
+			}
+			// We need to remove the pool last as the other devices block it
+			if hasPool {
+				if err := devmapper.RemoveDevice("docker-unit-tests-devices-pool"); err != nil {
+					panic(fmt.Errorf("Unable to remove existing device docker-unit-tests-devices-pool: %s", name, err))
+				}
+			}
+		}
+	}
+}
+
 func init() {
 	os.Setenv("TEST", "1")
 
@@ -99,6 +126,8 @@ func init() {
 
 	NetworkBridgeIface = unitTestNetworkBridge
 
+	cleanupDevMapper()
+
 	// Always start from a clean set of loopback mounts
 	err := os.RemoveAll(unitTestStoreDevicesBase)
 	if err != nil {