scripts/qmp/qmp.py | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-)
The readline() call returns partial data.
Keep appending until the JSON buffer is complete.
This fixes:
$ scripts/qmp/qmp-shell -v -p /tmp/qmp.sock
Traceback (most recent call last):
File "scripts/qmp/qmp-shell", line 456, in <module>
main()
File "scripts/qmp/qmp-shell", line 441, in main
qemu.connect(negotiate)
File "scripts/qmp/qmp-shell", line 284, in connect
self._greeting = super(QMPShell, self).connect(negotiate)
File "scripts/qmp/qmp.py", line 143, in connect
return self.__negotiate_capabilities()
File "scripts/qmp/qmp.py", line 71, in __negotiate_capabilities
greeting = self.__json_read()
File "scripts/qmp/qmp.py", line 85, in __json_read
resp = json.loads(data)
File "/usr/lib/python2.7/json/__init__.py", line 339, in loads
return _default_decoder.decode(s)
File "/usr/lib/python2.7/json/decoder.py", line 364, in decode
obj, end = self.raw_decode(s, idx=_w(s, 0).end())
File "/usr/lib/python2.7/json/decoder.py", line 380, in raw_decode
obj, end = self.scan_once(s, idx)
ValueError: Expecting object: line 1 column 3 (char 2)
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
---
Daniel suggested this is due to blocking i/o.
I'm sure there is a nicer/more pythonic way to do this, but this works for me,
sorry :)
scripts/qmp/qmp.py | 11 ++++++++---
1 file changed, 8 insertions(+), 3 deletions(-)
diff --git a/scripts/qmp/qmp.py b/scripts/qmp/qmp.py
index 5c8cf6a056..e8b55dfcc4 100644
--- a/scripts/qmp/qmp.py
+++ b/scripts/qmp/qmp.py
@@ -78,11 +78,16 @@ class QEMUMonitorProtocol(object):
raise QMPCapabilitiesError
def __json_read(self, only_event=False):
+ data = ""
while True:
- data = self.__sockfile.readline()
- if not data:
+ tmp = self.__sockfile.readline()
+ if not tmp:
return
- resp = json.loads(data)
+ data += tmp
+ try:
+ resp = json.loads(data)
+ except ValueError:
+ continue
if 'event' in resp:
self.logger.debug("<<< %s", resp)
self.__events.append(resp)
--
2.17.1
On Wed, Jun 06, 2018 at 01:53:19PM -0300, Philippe Mathieu-Daudé wrote: > The readline() call returns partial data. > Keep appending until the JSON buffer is complete. > > This fixes: > > $ scripts/qmp/qmp-shell -v -p /tmp/qmp.sock > Traceback (most recent call last): > File "scripts/qmp/qmp-shell", line 456, in <module> > main() > File "scripts/qmp/qmp-shell", line 441, in main > qemu.connect(negotiate) > File "scripts/qmp/qmp-shell", line 284, in connect > self._greeting = super(QMPShell, self).connect(negotiate) > File "scripts/qmp/qmp.py", line 143, in connect > return self.__negotiate_capabilities() > File "scripts/qmp/qmp.py", line 71, in __negotiate_capabilities > greeting = self.__json_read() > File "scripts/qmp/qmp.py", line 85, in __json_read > resp = json.loads(data) > File "/usr/lib/python2.7/json/__init__.py", line 339, in loads > return _default_decoder.decode(s) > File "/usr/lib/python2.7/json/decoder.py", line 364, in decode > obj, end = self.raw_decode(s, idx=_w(s, 0).end()) > File "/usr/lib/python2.7/json/decoder.py", line 380, in raw_decode > obj, end = self.scan_once(s, idx) > ValueError: Expecting object: line 1 column 3 (char 2) > > Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org> > --- > Daniel suggested this is due to blocking i/o. > > I'm sure there is a nicer/more pythonic way to do this, but this works for me, > sorry :) > > scripts/qmp/qmp.py | 11 ++++++++--- > 1 file changed, 8 insertions(+), 3 deletions(-) > > diff --git a/scripts/qmp/qmp.py b/scripts/qmp/qmp.py > index 5c8cf6a056..e8b55dfcc4 100644 > --- a/scripts/qmp/qmp.py > +++ b/scripts/qmp/qmp.py > @@ -78,11 +78,16 @@ class QEMUMonitorProtocol(object): > raise QMPCapabilitiesError > > def __json_read(self, only_event=False): > + data = "" > while True: > - data = self.__sockfile.readline() > - if not data: > + tmp = self.__sockfile.readline() > + if not tmp: > return > - resp = json.loads(data) > + data += tmp > + try: > + resp = json.loads(data) > + except ValueError: > + continue Downside is that we'll blindly loop if QEMU ever sends malformed data, but given the use context of this QMP shell that's not too serious. > if 'event' in resp: > self.logger.debug("<<< %s", resp) > self.__events.append(resp) If we get an event, we'll continue on the loop and append to 'data' again, so you must blank out data to "" after json.loads() succeeeds. Regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|
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