Improve Disk Detection

The previous implementation of list_block_devices used blockdev,
which would list partitions, software RAID and other devices as block devices.
By switching to lsblk, the agent can filter down to only physical block
devices, which is all the agent cares about for any of its operations.

This change adds two new fields to the BlockDevice class: model, a string of
the block devices reported model, and rotational, a boolean representing a
spinning disk (True) or a solid state disk (False). This data can be useful
for vendor hardware managers.

Change-Id: I385c3bb378c2c49385bca14a1d7efa074933becf
Closes-Bug: 1344351

1 files changed, 37 insertions, 12 deletions

diff --git a/ironic_python_agent/hardware.py b/ironic_python_agent/hardware.py
index ef5a0400..5aeb97ca 100644
--- a/ironic_python_agent/hardware.py
+++ b/ironic_python_agent/hardware.py
@@ -15,6 +15,7 @@
 import abc
 import functools
 import os
+import shlex
 
 import netifaces
 import psutil
@@ -47,11 +48,13 @@ class HardwareType(object):
 
 
 class BlockDevice(encoding.Serializable):
-    serializable_fields = ('name', 'size')
+    serializable_fields = ('name', 'model', 'size', 'rotational')
 
-    def __init__(self, name, size):
+    def __init__(self, name, model, size, rotational):
         self.name = name
+        self.model = model
         self.size = size
+        self.rotational = rotational
 
 
 class NetworkInterface(encoding.Serializable):
@@ -210,18 +213,40 @@ class GenericHardwareManager(HardwareManager):
         return Memory(int(psutil.phymem_usage().total))
 
     def list_block_devices(self):
-        report = utils.execute('blockdev', '--report',
+        """List all physical block devices
+
+        The switches we use for lsblk: P for KEY="value" output,
+        b for size output in bytes, d to exclude dependant devices
+        (like md or dm devices), i to ensure ascii characters only,
+        and  o to specify the fields we need
+
+        :return: A list of BlockDevices
+        """
+        report = utils.execute('lsblk', '-PbdioKNAME,MODEL,SIZE,ROTA,TYPE',
                                check_exit_code=[0])[0]
         lines = report.split('\n')
-        lines = [line.split() for line in lines if line != '']
-        startsec_idx = lines[0].index('StartSec')
-        device_idx = lines[0].index('Device')
-        size_idx = lines[0].index('Size')
-        # If a device doesn't start at sector 0, assume it is a partition
-        return [BlockDevice(line[device_idx],
-                            int(line[size_idx]))
-                for line
-                in lines[1:] if int(line[startsec_idx]) == 0]
+
+        devices = []
+        for line in lines:
+            device = {}
+            # Split into KEY=VAL pairs
+            vals = shlex.split(line)
+            for key, val in (v.split('=', 1) for v in vals):
+                device[key] = val.strip()
+            # Ignore non disk
+            if device.get('TYPE') != 'disk':
+                continue
+
+            # Ensure all required keys are at least present, even if blank
+            diff = set(['KNAME', 'MODEL', 'SIZE', 'ROTA']) - set(device.keys())
+            if diff:
+                raise errors.BlockDeviceError(
+                    '%s must be returned by lsblk.' % diff)
+            devices.append(BlockDevice(name='/dev/' + device['KNAME'],
+                                       model=device['MODEL'],
+                                       size=int(device['SIZE']),
+                                       rotational=bool(int(device['ROTA']))))
+        return devices
 
     def get_os_install_device(self):
         # Find the first device larger than 4GB, assume it is the OS disk