ceph-volume util create a device module for identifying devices

Signed-off-by: Alfredo Deza <adeza@redhat.com>

src/ceph-volume/ceph_volume/util/device.py

@@ -0,0 +1,96 @@
+import os
+from ceph_volume.api import lvm
+from ceph_volume.util import disk
+
+
+class Device(object):
+
+    def __init__(self, path):
+        self.path = path
+        # LVs can have a vg/lv path, while disks will have /dev/sda
+        self.abspath = path
+        self.lv_api = None
+        self.pvs_api = []
+        self.disk_api = {}
+        self._exists = None
+        self._is_lvm_member = None
+        self._parse()
+
+    def _parse(self):
+        # start with lvm since it can use an absolute or relative path
+        lv = lvm.get_lv_from_argument(self.path)
+        if lv:
+            self.lv_api = lv
+            self.abspath = lv.lv_path
+        else:
+            dev = disk.lsblk(self.path)
+            self.disk_api = dev
+            device_type = dev.get('TYPE', '')
+            # always check is this is an lvm member
+            if device_type in ['part', 'disk']:
+                self._set_lvm_membership()
+
+    def __repr__(self):
+        prefix = 'Unknown'
+        if self.is_lv:
+            prefix = 'LV'
+        elif self.is_partition:
+            prefix = 'Partition'
+        elif self.is_device:
+            prefix = 'Raw Device'
+        return '<%s: %s>' % (prefix, self.abspath)
+
+    def _set_lvm_membership(self):
+        if self._is_lvm_member is None:
+            # check if there was a pv created with the
+            # name of device
+            pvs = lvm.PVolumes()
+            pvs.filter(pv_name=self.abspath)
+            if not pvs:
+                self._is_lvm_member = False
+                return self._is_lvm_member
+            has_vgs = [pv.vg_name for pv in pvs]
+            if has_vgs:
+                self._is_lvm_member = True
+                self.pvs_api = pvs
+            else:
+                # this is contentious, if a PV is recognized by LVM but has no
+                # VGs, should we consider it as part of LVM? We choose not to
+                # here, because most likely, we need to use VGs from this PV.
+                self._is_lvm_member = False
+
+        return self._is_lvm_member
+
+    @property
+    def exists(self):
+        if self._exists is None:
+            self._exists = os.path.exists(self.abspath)
+        return self._exists
+
+    @property
+    def is_lvm_member(self):
+        if self._is_lvm_member is None:
+            self._set_lvm_membership()
+        return self._is_lvm_member
+
+    @property
+    def is_mapper(self):
+        if self._is_mapper is None:
+            self._is_mapper = self.path.startswith('/dev/mapper')
+        return self._is_mapper
+
+    @property
+    def is_lv(self):
+        return self.lv_api is not None
+
+    @property
+    def is_partition(self):
+        if self.disk_api:
+            return self.disk_api['TYPE'] == 'part'
+        return False
+
+    @property
+    def is_device(self):
+        if self.disk_api:
+            return self.disk_api['TYPE'] == 'device'
+        return False