When running QMP commands with very large response payloads, it is often
not easy to spot the info you want. If we can save the response to a
file then tools like 'grep' or 'jq' can be used to extract information.
For convenience of processing, we merge the QMP command and response
dictionaries together:
{
"arguments": {},
"execute": "query-kvm",
"return": {
"enabled": false,
"present": true
}
}
Example usage
$ ./scripts/qmp/qmp-shell-wrap -l q.log -p -- ./build/qemu-system-x86_64
-display none
Welcome to the QMP low-level shell!
Connected
(QEMU) query-kvm
{
"return": {
"enabled": false,
"present": true
}
}
(QEMU) query-mice
{
"return": [
{
"absolute": false,
"current": true,
"index": 2,
"name": "QEMU PS/2 Mouse"
}
]
}
$ jq --slurp '. | to_entries[] | select(.value.execute == "query-kvm") |
.value.return.enabled' < q.log
false
Signed-off-by: Daniel P. Berrangé <berra...@redhat.com>
---
python/qemu/qmp/qmp_shell.py | 27 ++++++++++++++++++++-------
1 file changed, 20 insertions(+), 7 deletions(-)
diff --git a/python/qemu/qmp/qmp_shell.py b/python/qemu/qmp/qmp_shell.py
index 12f7d28afc..a50c3f1bc7 100644
--- a/python/qemu/qmp/qmp_shell.py
+++ b/python/qemu/qmp/qmp_shell.py
@@ -165,7 +165,8 @@ class QMPShell(qmp.QEMUMonitorProtocol):
def __init__(self, address: qmp.SocketAddrT,
pretty: bool = False,
verbose: bool = False,
- server: bool = False):
+ server: bool = False,
+ logfile: str = None):
super().__init__(address, server=server)
self._greeting: Optional[QMPMessage] = None
self._completer = QMPCompleter()
@@ -175,6 +176,10 @@ def __init__(self, address: qmp.SocketAddrT,
'.qmp-shell_history')
self.pretty = pretty
self.verbose = verbose
+ self.logfile = None
+
+ if logfile is not None:
+ self.logfile = open(logfile, "w")
def close(self) -> None:
# Hook into context manager of parent to save shell history.
@@ -315,11 +320,11 @@ def _build_cmd(self, cmdline: str) ->
Optional[QMPMessage]:
self._cli_expr(cmdargs[1:], qmpcmd['arguments'])
return qmpcmd
- def _print(self, qmp_message: object) -> None:
+ def _print(self, qmp_message: object, fh=sys.stdout) -> None:
jsobj = json.dumps(qmp_message,
indent=4 if self.pretty else None,
sort_keys=self.pretty)
- print(str(jsobj))
+ print(str(jsobj), file=fh)
def _execute_cmd(self, cmdline: str) -> bool:
try:
@@ -342,6 +347,9 @@ def _execute_cmd(self, cmdline: str) -> bool:
print('Disconnected')
return False
self._print(resp)
+ if self.logfile is not None:
+ cmd = {**qmpcmd, **resp}
+ self._print(cmd, fh=self.logfile)
return True
def connect(self, negotiate: bool = True) -> None:
@@ -409,8 +417,9 @@ class HMPShell(QMPShell):
def __init__(self, address: qmp.SocketAddrT,
pretty: bool = False,
verbose: bool = False,
- server: bool = False):
- super().__init__(address, pretty, verbose, server)
+ server: bool = False,
+ logfile: str = None):
+ super().__init__(address, pretty, verbose, server, logfile)
self._cpu_index = 0
def _cmd_completion(self) -> None:
@@ -503,6 +512,8 @@ def main() -> None:
help='Verbose (echo commands sent and received)')
parser.add_argument('-p', '--pretty', action='store_true',
help='Pretty-print JSON')
+ parser.add_argument('-l', '--logfile',
+ help='Save log of all QMP messages to PATH')
default_server = os.environ.get('QMP_SOCKET')
parser.add_argument('qmp_server', action='store',
@@ -521,7 +532,7 @@ def main() -> None:
parser.error(f"Bad port number: {args.qmp_server}")
return # pycharm doesn't know error() is noreturn
- with shell_class(address, args.pretty, args.verbose) as qemu:
+ with shell_class(address, args.pretty, args.verbose, args.logfile) as qemu:
try:
qemu.connect(negotiate=not args.skip_negotiation)
except qmp.QMPConnectError:
@@ -545,6 +556,8 @@ def main_wrap() -> None:
help='Verbose (echo commands sent and received)')
parser.add_argument('-p', '--pretty', action='store_true',
help='Pretty-print JSON')
+ parser.add_argument('-l', '--logfile',
+ help='Save log of all QMP messages to PATH')
parser.add_argument('command', nargs=argparse.REMAINDER,
help='QEMU command line to invoke')
@@ -568,7 +581,7 @@ def main_wrap() -> None:
parser.error(f"Bad port number: {socketpath}")
return # pycharm doesn't know error() is noreturn
- with shell_class(address, args.pretty, args.verbose, True) as qemu:
+ with shell_class(address, args.pretty, args.verbose, True, args.logfile)
as qemu:
qemuproc = Popen(cmd)
try:
--
2.33.1
