Re: [Qemu-devel] [PATCH v3 0/4] scripts: qmp-shell: add transaction support

[Kashyap Chamarthy <kchamart@redhat.com>]

On Thu, Apr 23, 2015 at 10:34:57AM -0400, John Snow wrote:
> The qmp-shell is a little rudimentary, but it can be hacked
> to give us some transactional support without too much difficulty.
> 
> (1) Prep.
> (2) Add support for serializing json arrays
> (3) Allow users to use 'single quotes' instead of "double quotes"
> (4) Add a special transaction( ... ) syntax that lets users
>     build up transactional commands using the existing qmp shell
>     syntax to define each action.
> (5) Add a verbose flag to display generated QMP commands.
> 
> The parsing is not as robust as one would like, but this suffices
> without adding a proper parser.
> 
> Design considerations:
> 
> (1) Try not to disrupt the existing design of the qmp-shell. The existing
>     API is not disturbed.
> 
> (2) Pick a "magic token" such that it could not be confused for legitimate
>     QMP/JSON syntax. Parentheses are used for this purpose.
> 
> ===
> v3:
> ===
> 
>  - Folding in hotfix from list (import ast)

Seems like a regression from your v2.

It fails here, even for a non-transaction command, with your patch series
applied:

  (QEMU) blockdev-snapshot-internal-sync device=drive-ide0-0-0 name=snapshot0
  Error while parsing command line: global name '_QMPShell__parse_value' is not defined
  command format: <command-name>  [arg-name1=arg1] ... [arg-nameN=argN]


Earlier the day, with v2, I was able to test it correctly:

 (QEMU) transaction(
 TRANS> blockdev-snapshot-sync device=drive-ide0-0-0 snapshot-file=./ext-snap1.qcow2 format=qcow2
 TRANS> blockdev-snapshot-internal-sync device=drive-ide0-0-0 name=snapshot0
 TRANS> )
 {u'return': {}}
 (QEMU)

-- 
/kashyap


> 
> ===
> v2:
> ===
> 
>  - Squash patches 2 & 3:
>   - Remove wholesale replacement of single quotes, in favor of try blocks
>     that attempt to parse as pure JSON, then as Python.
>   - Factored out the value parser block to accomplish the above.
>   - Allow both true/True and false/False for values.
>  - Fix typo in patch 3 cover letter. (was patch 4.)
> 
> John Snow (4):
>   scripts: qmp-shell: refactor helpers
>   scripts: qmp-shell: Expand support for QMP expressions
>   scripts: qmp-shell: add transaction subshell
>   scripts: qmp-shell: Add verbose flag
> 
>  scripts/qmp/qmp-shell | 126 ++++++++++++++++++++++++++++++++++++++------------
>  1 file changed, 96 insertions(+), 30 deletions(-)
> 
> -- 
> 2.1.0
> 

-- 
/kashyap