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
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Message-id: 20220128161157.36261-3-berrange@redhat.com
Signed-off-by: John Snow <jsnow@redhat.com>
With the current 'qmp-shell' tool developers must first spawn QEMU with
a suitable -qmp arg and then spawn qmp-shell in a separate terminal
pointing to the right socket.
With 'qmp-shell-wrap' developers can ignore QMP sockets entirely and
just pass the QEMU command and arguments they want. The program will
listen on a UNIX socket and tell QEMU to connect QMP to that.
For example, this:
# qmp-shell-wrap -- qemu-system-x86_64 -display none
Is roughly equivalent of running:
# qemu-system-x86_64 -display none -qmp qmp-shell-1234 &
# qmp-shell qmp-shell-1234
Except that 'qmp-shell-wrap' switches the socket peers around so that
it is the UNIX socket server and QEMU is the socket client. This makes
QEMU reliably go away when qmp-shell-wrap exits, closing the server
socket.
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Message-id: 20220128161157.36261-2-berrange@redhat.com
[Edited for rebase. --js]
Signed-off-by: John Snow <jsnow@redhat.com>
Daniel P. Berrangé