On 03/03/2017 02:26 PM, Nir Soffer wrote:
> On Fri, Mar 3, 2017 at 8:54 PM, John Snow <js...@redhat.com> wrote:
>> Use the existing readline history function we are utilizing
>> to provide persistent command history across instances of qmp-shell.
>>
>> This assists entering debug commands across sessions that may be
>> interrupted by QEMU sessions terminating, where the qmp-shell has
>> to be relaunched.
>>
>> Signed-off-by: John Snow <js...@redhat.com>
>> ---
>>
>> v2: Adjusted the errors to whine about non-ENOENT errors, but still
>> intercept all errors as non-fatal.
>> Save history atexit() to match bash standard behavior
>>
>> scripts/qmp/qmp-shell | 19 +++++++++++++++++++
>> 1 file changed, 19 insertions(+)
>>
>> diff --git a/scripts/qmp/qmp-shell b/scripts/qmp/qmp-shell
>> index 0373b24..55a8285 100755
>> --- a/scripts/qmp/qmp-shell
>> +++ b/scripts/qmp/qmp-shell
>> @@ -70,6 +70,9 @@ import json
>> import ast
>> import readline
>> import sys
>> +import os
>> +import errno
>> +import atexit
>>
>> class QMPCompleter(list):
>> def complete(self, text, state):
>> @@ -109,6 +112,7 @@ class QMPShell(qmp.QEMUMonitorProtocol):
>> self._pretty = pretty
>> self._transmode = False
>> self._actions = list()
>> + self._histfile = os.path.join(os.path.expanduser('~'),
>> '.qmp_history')
>>
>> def __get_address(self, arg):
>> """
>> @@ -137,6 +141,21 @@ class QMPShell(qmp.QEMUMonitorProtocol):
>> # XXX: default delimiters conflict with some command names (eg.
>> query-),
>> # clearing everything as it doesn't seem to matter
>> readline.set_completer_delims('')
>> + try:
>> + readline.read_history_file(self._histfile)
>> + except Exception as e:
>> + if isinstance(e, IOError) and e.errno == errno.ENOENT:
>> + # File not found. No problem.
>> + pass
>> + else:
>> + print "Failed to read history '%s'; %s" % (self._histfile,
>> e)
>
> I would handle only IOError, since any other error means a bug in this code
> or in the underlying readline library, and the best way to handle this is to
> let it fail loudly.
>
Disagree. No reason to stop the shell from working because a QOL feature
didn't initialize correctly.
The warning will be enough to solicit reports and fixes if necessary.
>> + atexit.register(self.__save_history)
>> +
>> + def __save_history(self):
>> + try:
>> + readline.write_history_file(self._histfile)
>> + except Exception as e:
>> + print "Failed to save history file '%s'; %s" % (self._histfile,
>> e)
>>
>> def __parse_value(self, val):
>> try:
>
> But I think this is good enough and useful as is.
>
> Reviewed-by: Nir Soffer <nir...@gmail.com>
>
