Add find_efi_partition, deprecate get_uefi_disk_identifier

The get_uefi_disk_identifier function is currently unused in both
ironic and IPA. Furthermore, its name is confusing: it returns
the UEFI partition UUID, not the disk identifier, unlike the
similarly named get_disk_identifier.

This change imports get_efi_part_on_device from IPA as
find_efi_partition. The only difference is that it returns
a complete partition record rather than only the number.

Change-Id: I424d04adb6ccbb3daa99daa5c860cbb81332c02e

ironic_lib/disk_utils.py

@@ -24,6 +24,7 @@ import shutil
 import stat
 import tempfile
 import time
+import warnings
 
 from oslo_concurrency import processutils
 from oslo_config import cfg
@@ -212,19 +213,37 @@ def get_device_information(device, probe=False, fields=None):
         return {}
 
 
+def find_efi_partition(device):
+    """Looks for the EFI partition on a given device.
+
+    A boot partition on a GPT disk is assumed to be an EFI partition as well.
+
+    :param device: the name of the device
+    :return: the EFI partition record from `list_partitions` or None
+    """
+    is_gpt = get_partition_table_type(device) == 'gpt'
+    for part in list_partitions(device):
+        flags = {x.strip() for x in part['flags'].split(',')}
+        if 'esp' in flags or ('boot' in flags and is_gpt):
+            LOG.debug("Found EFI partition %s on device %s", part, device)
+            return part
+    else:
+        LOG.debug("No efi partition found on device %s", device)
+
+
 def get_uefi_disk_identifier(dev):
     """Get the uuid from the disk being exposed by the ramdisk.
 
-    This uuid is appended to the pxe config which will then be set as the root
-    and load the bootx64.efi file using chainloader and boot the machine.
-    This is helpful in deployments to nodes with multiple disks.
-
-    https://wiki.gentoo.org/wiki/GRUB2/Chainloading
+    DEPRECATED: use find_efi_partition with get_device_information instead.
 
     :param dev: Path for the already populated disk device.
     :raises InstanceDeployFailure: Image is not UEFI bootable.
     :returns: The UUID of the partition.
     """
+    warnings.warn("get_uefi_disk_identifier is deprecated, use "
+                  "find_efi_partition and get_partition_information instead",
+                  DeprecationWarning)
+
     partition_id = None
     try:
         report, _ = utils.execute('fdisk', '-l', dev, run_as_root=True)

ironic_lib/tests/test_disk_utils.py

@@ -2047,3 +2047,58 @@ class GetPartitionTableTypeTestCase(base.IronicLibTestCase):
         mock_get_device_info.return_value = {}
         self.assertIsNone(disk_utils.get_partition_table_type('/dev/fake'))
         mock_get_device_info.assert_called_once_with('/dev/fake', probe=True)
+
+
+PARTED_OUTPUT_UNFORMATTED = '''Model: whatever
+Disk /dev/sda: 450GB
+Sector size (logical/physical): 512B/512B
+Partition Table: {}
+Disk Flags:
+
+Number  Start   End     Size    File system  Name  Flags
+14      1049kB  5243kB  4194kB                     bios_grub
+15      5243kB  116MB   111MB   fat32              boot, esp
+ 1      116MB   2361MB  2245MB  ext4
+'''
+
+
+@mock.patch.object(disk_utils, 'list_partitions', autospec=True)
+@mock.patch.object(disk_utils, 'get_partition_table_type', autospec=True)
+class FindEfiPartitionTestCase(base.IronicLibTestCase):
+
+    def test_find_efi_partition(self, mocked_type, mocked_parts):
+        mocked_parts.return_value = [
+            {'number': '1', 'flags': ''},
+            {'number': '14', 'flags': 'bios_grub'},
+            {'number': '15', 'flags': 'esp, boot'},
+        ]
+        ret = disk_utils.find_efi_partition('/dev/sda')
+        self.assertEqual({'number': '15', 'flags': 'esp, boot'}, ret)
+
+    def test_find_efi_partition_only_boot_flag_gpt(self, mocked_type,
+                                                   mocked_parts):
+        mocked_type.return_value = 'gpt'
+        mocked_parts.return_value = [
+            {'number': '1', 'flags': ''},
+            {'number': '14', 'flags': 'bios_grub'},
+            {'number': '15', 'flags': 'boot'},
+        ]
+        ret = disk_utils.find_efi_partition('/dev/sda')
+        self.assertEqual({'number': '15', 'flags': 'boot'}, ret)
+
+    def test_find_efi_partition_only_boot_flag_mbr(self, mocked_type,
+                                                   mocked_parts):
+        mocked_type.return_value = 'msdos'
+        mocked_parts.return_value = [
+            {'number': '1', 'flags': ''},
+            {'number': '14', 'flags': 'bios_grub'},
+            {'number': '15', 'flags': 'boot'},
+        ]
+        self.assertIsNone(disk_utils.find_efi_partition('/dev/sda'))
+
+    def test_find_efi_partition_not_found(self, mocked_type, mocked_parts):
+        mocked_parts.return_value = [
+            {'number': '1', 'flags': ''},
+            {'number': '14', 'flags': 'bios_grub'},
+        ]
+        self.assertIsNone(disk_utils.find_efi_partition('/dev/sda'))