Rename block-device -> block-devices

Add support for block-devices, but still only accept one block device.

Add tests for parsing the device block list.

Change-Id: I78fe3b9e617a7da75145a2695bee312cf3685246

README.md

@@ -9,7 +9,7 @@ The lxd charm can be used in-conjunction with any principle charm to setup and e
     juju deploy cs:~openstack-charmers-next/wily/nova-compute
     juju set nova-compute virt-type=lxd
     juju deploy cs:~openstack-charmers-next/wily/lxd
-    juju set lxd block-device=/dev/sdb storage-type=lvm
+    juju set lxd block-devices=/dev/sdb storage-type=lvm
     juju add-relation lxd nova-compute
 
 At this point in time, LXD is only supported on Ubuntu 15.10 or above, in-conjunction with OpenStack Liberty (provided as part of Ubuntu 15.10).

config.yaml

@@ -6,15 +6,15 @@ options:
       Repository from which to install LXD.  May be one of the following:
       distro (default), ppa:somecustom/ppa, a deb url sources entry,
       or a supported release pocket
-  block-device:
+  block-devices:
     type: string
     default:
     description: |
-       Device to be used to back LXD storage. May be an valid block
-       device or a path and size to a local file (/path/to/file.img|$sizeG),
-       which will be created and used as a loopback device (for testing only).
+       A space-separated list of devices to use to back the LXD storage. Items
+       in this list should be valid block device paths. Entries that are not
+       found will be ignored.
        .
-       This will be use to store lxd containers.
+       Currently, only the the first block device in the list will be considered.
   overwrite:
     default: False
     type: boolean

hooks/lxd_utils.py

@@ -143,6 +143,15 @@ def configure_lxd_source(user='ubuntu'):
     service_start('lxd')
 
 
+def get_block_devices():
+    """Returns a list of block devices provided by the config."""
+    lxd_block_devices = config('block-devices')
+    if lxd_block_devices is None:
+        return []
+    else:
+        return lxd_block_devices.split(' ')
+
+
 def configure_lxd_block():
     '''Configure a block device for use by LXD for containers'''
     log('Configuring LXD container storage')
@@ -150,10 +159,13 @@ def configure_lxd_block():
         log('/var/lib/lxd already configured, skipping')
         return
 
-    lxd_block_device = config('block-device')
-    if not lxd_block_device:
-        log('block device is not provided - skipping')
+    lxd_block_devices = get_block_devices()
+    if len(lxd_block_devices) < 1:
+        log('block devices not provided - skipping')
         return
+    if len(lxd_block_devices) > 1:
+        raise NotImplementedError('Multiple block devices are not supported.')
+    lxd_block_device = lxd_block_devices[0]
 
     dev = None
     if lxd_block_device.startswith('/dev/'):

tests/basic_deployment.py

@@ -93,7 +93,7 @@ class LXDBasicDeployment(OpenStackAmuletDeployment):
         }
 
         lxd_config = {
-            'block-device': '/dev/vdb',
+            'block-devices': '/dev/vdb',
             'ephemeral-unmount': '/mnt',
             'storage-type': 'lvm',
             'overwrite': True

unit_tests/test_lxd_utils.py

@@ -85,3 +85,37 @@ class TestLXDUtilsCreateAndImportBusyboxImage(testing.CharmTestCase):
         Popen_rv.stdout.read.assert_called_once_with()
         stat.assert_called_with('/bin/busybox')
         mock_open.assert_called_once_with('/bin/busybox', 'rb')
+
+
+class TestGetBlockDevices(testing.CharmTestCase):
+    """Tests for hooks.lxd_utils.get_block_devices."""
+
+    TO_PATCH = [
+        'config',
+    ]
+
+    def setUp(self):
+        super(TestGetBlockDevices, self).setUp(
+            lxd_utils, self.TO_PATCH)
+        self.config.side_effect = self.test_config.get
+
+    def testEmpty(self):
+        """When no config is specified, an empty list is returned."""
+        devices = lxd_utils.get_block_devices()
+
+        self.assertEqual([], devices)
+
+    def testSingleDevice(self):
+        """Return a list with the single device."""
+        self.test_config.set('block-devices', '/dev/vdb')
+        devices = lxd_utils.get_block_devices()
+
+        self.assertEqual(['/dev/vdb'], devices)
+
+    def testMultipleDevices(self):
+        """Return a list with all devices."""
+        self.test_config.set('block-devices', '/dev/vdb /dev/vdc')
+
+        devices = lxd_utils.get_block_devices()
+
+        self.assertEqual(['/dev/vdb', '/dev/vdc'], devices)