On 5/25/22 18:06, Daniel P. Berrangé wrote:
On Wed, Mar 16, 2022 at 10:54:55AM +0100, Damien Hedde wrote:
+def raw_load(file: TextIO) -> List[QMPMessage]:
+ """parse a raw qmp command file.
+
+ JSON formatted commands can expand on several lines but must
+ be separated by an end-of-line (two commands can not share the
+ same line).
+ File must not end with empty lines.
+ """
+ cmds: List[QMPMessage] = []
+ linecnt = 0
+ while True:
+ buf = file.readline()
+ if not buf:
+ return cmds
If you change this to 'break'...
+ prev_err_pos = None
+ buf_linecnt = 1
+ while True:
+ try:
+ cmds.append(json.loads(buf))
...and this to
yield json.loads(buf)
then....
+ break
+ except json.JSONDecodeError as err:
+ if prev_err_pos == err.pos:
+ # adding a line made no progress so
+ # + either we're at EOF and json data is truncated
+ # + or the parsing error is before
+ raise QmpRawDecodeError(err.msg, linecnt + err.lineno,
+ err.colno) from err
+ prev_err_pos = err.pos
+ buf += file.readline()
+ buf_linecnt += 1
+ linecnt += buf_linecnt
+
+
+def report_error(msg: str) -> None:
+ """Write an error to stderr."""
+ sys.stderr.write('ERROR: %s\n' % msg)
+
+
+def main() -> None:
+ """
+ qmp-send entry point: parse command line arguments and start the REPL.
+ """
+ parser = argparse.ArgumentParser(
+ description="""
+ Send raw qmp commands to qemu as long as they succeed. It either
+ connects to a remote qmp server using the provided socket or wrap
+ the qemu process. It stops sending the provided commands when a
+ command fails (disconnection or error response).
+ """,
+ epilog="""
+ When qemu wrap option is used, this script waits for qemu
+ to terminate but never send any quit or kill command. This
+ needs to be done manually.
+ """)
+
+ parser.add_argument('-f', '--file', action='store',
+ help='Input file containing the commands')
+ parser.add_argument('-s', '--socket', action='store',
+ help='< UNIX socket path | TCP address:port >')
+ parser.add_argument('-v', '--verbose', action='store_true',
+ help='Verbose (echo commands sent and received)')
+ parser.add_argument('-p', '--pretty', action='store_true',
+ help='Pretty-print JSON')
+
+ parser.add_argument('--wrap', nargs=argparse.REMAINDER,
+ help='QEMU command line to invoke')
+
+ args = parser.parse_args()
+
+ socket = args.socket
+ wrap_qemu = args.wrap is not None
+
+ if wrap_qemu:
+ if len(args.wrap) != 0:
+ qemu_cmdline = args.wrap
+ else:
+ qemu_cmdline = ["qemu-system-x86_64"]
+ if socket is None:
+ socket = "qmp-send-wrap-%d" % os.getpid()
+ qemu_cmdline += ["-qmp", "unix:%s" % socket]
+
+ try:
+ address = QMPSend.parse_address(socket)
+ except QMPBadPortError:
+ parser.error(f"Bad port number: {socket}")
+ return # pycharm doesn't know error() is noreturn
+
+ try:
+ with open(args.file, mode='rt', encoding='utf8') as file:
+ qmp_cmds = raw_load(file)
+ except QmpRawDecodeError as err:
+ report_error(str(err))
+ sys.exit(1)
...change this to
fh = sys.stdin
if args.file is not None and args.file != '-':
fh = open(args.file, mode='rt', encoding='utf8')
....
+
+ try:
+ with QMPSend(address, args.pretty, args.verbose,
+ server=wrap_qemu) as qmp:
+ # starting with python 3.7 we could use contextlib.nullcontext
+ qemu = Popen(qemu_cmdline) if wrap_qemu else contextlib.suppress()
+ with qemu:
+ try:
+ qmp.setup_connection()
+ except ConnectError as err:
+ if isinstance(err.exc, OSError):
+ report_error(f"Couldn't connect to {socket}: {err!s}")
+ else:
+ report_error(str(err))
+ sys.exit(1)
+ try:
+ for cmd in qmp_cmds:
...finally this to
for cmd in raw_load(fh)
This means we can use qmp-send in a pipeline with commands
sent to QEMU on the fly as they arrive, rather than having
to read all the commands upfront before QEMU is started.
Yes. I was not sure which way was "better" between reading on the fly or
buffering everything before. In we want pipelining, we don't have much
choice.
BTW, as an example usage I was trying your impl here in the following
way to extract information about CPUs that are deprecated
echo -e '{ "execute": "query-cpu-definitions"}\n{"execute": "quit"}' | \
qmp-send -v -p --wrap ./build/qemu-system-x86_64 -nodefaults -vnc :1 | \
jq -r --slurp '.[1].return[] | [.name, .deprecated] | @csv'
+ qmp.execute_cmd(cmd)
+ except QMPError as err:
+ report_error(str(err))
+ sys.exit(1)
+ finally:
+ if wrap_qemu:
+ os.unlink(socket)
+
+
+if __name__ == '__main__':
+ main()
With regards,
Daniel
