Detect whether qmp-shell's standard input is not a TTY; in such case,
assume a non-interactive mode, which suppresses the welcome banner and
the "(QEMU)" prompt. This allows for easier consumption of qmp-shell's
output in scripts.
Example usage before this change:
$ printf "query-status\nquery-kvm\n" | sudo scripts/qmp/qmp-shell
qmp-unix-sock
Welcome to the QMP low-level shell!
Connected to QEMU 5.1.50
(QEMU) {"return": {"status": "running", "singlestep": false, "running":
true}}
(QEMU) {"return": {"enabled": true, "present": true}}
(QEMU)
Example usage after this change:
$ printf "query-status\nquery-kvm\n" | sudo scripts/qmp/qmp-shell
qmp-unix-sock
{"return": {"status": "running", "singlestep": false, "running": true}}
{"return": {"enabled": true, "present": true}}
Signed-off-by: Dov Murik <dovmu...@linux.vnet.ibm.com>
---
Notes:
Note that this might be considered a breaking change; if users have
automated scripts which assume that qmp-shell prints 3 lines of banner,
this change will break their scripts. If there are special
considerations/procedures for breaking changes, please let me know.
The rationale behaind the TTY check is to imitate python's behaviour:
$ python3
Python 3.7.5 (default, Apr 19 2020, 20:18:17)
[GCC 9.2.1 20191008] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> print(19+23)
42
>>>
$ echo 'print(19+23)' | python3
42
scripts/qmp/qmp-shell | 19 +++++++++++++++++--
1 file changed, 17 insertions(+), 2 deletions(-)
diff --git a/scripts/qmp/qmp-shell b/scripts/qmp/qmp-shell
index b4d06096ab..9336066fa8 100755
--- a/scripts/qmp/qmp-shell
+++ b/scripts/qmp/qmp-shell
@@ -288,6 +288,8 @@ class QMPShell(qmp.QEMUMonitorProtocol):
self.__completer_setup()
def show_banner(self, msg='Welcome to the QMP low-level shell!'):
+ if not self._interactive:
+ return
print(msg)
if not self._greeting:
print('Connected')
@@ -300,6 +302,15 @@ class QMPShell(qmp.QEMUMonitorProtocol):
return "TRANS> "
return "(QEMU) "
+ def read_command(self, prompt):
+ if self._interactive:
+ return input(prompt)
+ else:
+ line = sys.stdin.readline()
+ if not line:
+ raise EOFError
+ return line
+
def read_exec_command(self, prompt):
"""
Read and execute a command.
@@ -307,7 +318,7 @@ class QMPShell(qmp.QEMUMonitorProtocol):
@return True if execution was ok, return False if disconnected.
"""
try:
- cmdline = input(prompt)
+ cmdline = self.read_command(prompt)
except EOFError:
print()
return False
@@ -322,6 +333,9 @@ class QMPShell(qmp.QEMUMonitorProtocol):
def set_verbosity(self, verbose):
self._verbose = verbose
+ def set_interactive(self, interactive):
+ self._interactive = interactive
+
class HMPShell(QMPShell):
def __init__(self, address):
QMPShell.__init__(self, address)
@@ -449,8 +463,9 @@ def main():
except qemu.error:
die('Could not connect to %s' % addr)
- qemu.show_banner()
qemu.set_verbosity(verbose)
+ qemu.set_interactive(sys.stdin.isatty())
+ qemu.show_banner()
while qemu.read_exec_command(qemu.get_prompt()):
pass
qemu.close()
--
2.20.1
