qemu/scripts/render_block_graph.py

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#!/usr/bin/env python3
#
# Render Qemu Block Graph
#
# Copyright (c) 2018 Virtuozzo International GmbH. All rights reserved.
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
#
import os
import sys
import subprocess
import json
from graphviz import Digraph
sys.path.append(os.path.join(os.path.dirname(__file__), '..', 'python'))
from qemu.qmp import (
QEMUMonitorProtocol,
QMPResponseError,
)
def perm(arr):
s = 'w' if 'write' in arr else '_'
s += 'r' if 'consistent-read' in arr else '_'
s += 'u' if 'write-unchanged' in arr else '_'
s += 'g' if 'graph-mod' in arr else '_'
s += 's' if 'resize' in arr else '_'
return s
def render_block_graph(qmp, filename, format='png'):
'''
Render graph in text (dot) representation into "@filename" and
representation in @format into "@filename.@format"
'''
bds_nodes = qmp.command('query-named-block-nodes')
bds_nodes = {n['node-name']: n for n in bds_nodes}
job_nodes = qmp.command('query-block-jobs')
job_nodes = {n['device']: n for n in job_nodes}
block_graph = qmp.command('x-debug-query-block-graph')
graph = Digraph(comment='Block Nodes Graph')
graph.format = format
graph.node('permission symbols:\l'
' w - Write\l'
' r - consistent-Read\l'
' u - write - Unchanged\l'
' g - Graph-mod\l'
' s - reSize\l'
'edge label scheme:\l'
' <child type>\l'
' <perm>\l'
' <shared_perm>\l', shape='none')
for n in block_graph['nodes']:
if n['type'] == 'block-driver':
info = bds_nodes[n['name']]
label = n['name'] + ' [' + info['drv'] + ']'
if info['drv'] == 'file':
label += '\n' + os.path.basename(info['file'])
shape = 'ellipse'
elif n['type'] == 'block-job':
info = job_nodes[n['name']]
label = info['type'] + ' job (' + n['name'] + ')'
shape = 'box'
else:
assert n['type'] == 'block-backend'
label = n['name'] if n['name'] else 'unnamed blk'
shape = 'box'
graph.node(str(n['id']), label, shape=shape)
for e in block_graph['edges']:
label = '%s\l%s\l%s\l' % (e['name'], perm(e['perm']),
perm(e['shared-perm']))
graph.edge(str(e['parent']), str(e['child']), label=label)
graph.render(filename)
class LibvirtGuest():
def __init__(self, name):
self.name = name
def command(self, cmd):
# only supports qmp commands without parameters
m = {'execute': cmd}
ar = ['virsh', 'qemu-monitor-command', self.name, json.dumps(m)]
reply = json.loads(subprocess.check_output(ar))
if 'error' in reply:
raise QMPResponseError(reply)
return reply['return']
if __name__ == '__main__':
obj = sys.argv[1]
out = sys.argv[2]
if os.path.exists(obj):
# assume unix socket
qmp = QEMUMonitorProtocol(obj)
qmp.connect()
else:
# assume libvirt guest name
qmp = LibvirtGuest(obj)
render_block_graph(qmp, out)