Re: [Qemu-block] [PATCH v2 2/3] scripts: add render_block_graph function for QEMUMachine

[Vladimir Sementsov-Ogievskiy]

17.08.2018 21:25, Eduardo Habkost wrote:
> On Fri, Aug 17, 2018 at 09:04:39PM +0300, Vladimir Sementsov-Ogievskiy wrote:
> > Render block nodes graph with help of graphviz. This new function is
> > for debugging, so there is no sense to put it into qemu.py as a method
> > of QEMUMachine. Let's instead put it separately.
> >
> > Signed-off-by: Vladimir Sementsov-Ogievskiy <address@hidden>
> > ---
> >   scripts/render_block_graph.py | 78 +++++++++++++++++++++++++++++++++++++++++++
> >   1 file changed, 78 insertions(+)
> >   create mode 100644 scripts/render_block_graph.py
> >
> > diff --git a/scripts/render_block_graph.py b/scripts/render_block_graph.py
> > new file mode 100644
> > index 0000000000..7048a0bac8
> > --- /dev/null
> > +++ b/scripts/render_block_graph.py
> > @@ -0,0 +1,78 @@
> > +# Render Qemu Block Graph
> [...]
>
> What about making the script work from the command-line?
>
> Signed-off-by: Eduardo Habkost <address@hidden>
> ---
> diff --git a/scripts/render_block_graph.py b/scripts/render_block_graph.py
> old mode 100644
> new mode 100755
> index 7048a0bac8..e29fe0fc41
> --- a/scripts/render_block_graph.py
> +++ b/scripts/render_block_graph.py
> @@ -1,3 +1,4 @@
> +#!/usr/bin/env python
>   # Render Qemu Block Graph
>   #
>   # Copyright (c) 2017 Parallels International GmbH
> @@ -16,8 +17,9 @@
>   # along with this program.  If not, see <http://www.gnu.org/licenses/>.
>   #
>   
> -import os
> +import os, sys
>   from graphviz import Digraph
> +from qmp.qmp import QEMUMonitorProtocol
>   
>   def perm(arr):
>       s = 'w' if 'write' in arr else '_'
> @@ -27,16 +29,16 @@ def perm(arr):
>       s += 's' if 'resize' in arr else '_'
>       return s
>   
> -def render_block_graph(vm, filename, pointers=False, format='png'):
> +def render_block_graph(qmp, filename, pointers=False, format='png'):
>       '''
>       Render graph in text (dot) representation into "@filename" and
>       representation in @format into "@address@hidden"
>       '''
>   
> -    nodes = vm.command('query-named-block-nodes')
> +    nodes = qmp.command('query-named-block-nodes')
>       nodes_info = {n['node-name']: n for n in nodes}
>   
> -    block_graph = vm.command('x-query-block-graph')
> +    block_graph = qmp.command('x-query-block-graph')
>   
>       graph = Digraph(comment='Block Nodes Graph')
>       graph.format = format
> @@ -76,3 +78,9 @@ def render_block_graph(vm, filename, pointers=False, 
> format='png'):
>           graph.edge(str(e['parent']), str(e['child']), label=label)
>   
>       graph.render(filename)
> +
> +if __name__ == '__main__':
> +    #TODO: use argparse for command-line arguments
> +    qmp = QEMUMonitorProtocol(sys.argv[1])
> +    qmp.connect()
> +    render_block_graph(qmp, sys.argv[2])

Cool, thanks.

so, how to use it then?

for python iotest a proper parameter would be vm._qmp, yes?

is there a way to dump running libvirt vm graph?

I've started libvirt guest, qemu process has cmdline parameters
-chardev 
socket,id=charmonitor,path=/var/lib/libvirt/qemu/domain-3-tmp/monitor.sock,server,nowait
-mon chardev=charmonitor,id=monitor,mode=control

command
virsh qemu-monitor-command tmp '{"execute": "x-query-block-graph"}'
works fine,

but script hangs on connection:
# python ./scripts/render_block_graph.py 
/var/lib/libvirt/qemu/domain-3-tmp/monitor.sock
^CTraceback (most recent call last):
  File "./scripts/render_block_graph.py", line 85, in <module>
    qmp.connect()
  File "/work/src/qemu/up-new-fleecing/scripts/qmp/qmp.py", line 140, 
in connect
    self.__sock.connect(self.__address)
  File "/usr/lib64/python2.7/socket.py", line 224, in meth
    return getattr(self._sock,name)(*args)
KeyboardInterrupt

./scripts/qmp/qmp-shell /var/lib/libvirt/qemu/domain-3-tmp/monitor.sock
outputs nothing...


--
Best regards,
Vladimir