python: support recording QMP session to a file

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>

1 files changed, 3 insertions, 0 deletions

diff --git a/python/setup.cfg b/python/setup.cfg
index 0959603..9821db9 100644
--- a/python/setup.cfg
+++ b/python/setup.cfg
@@ -114,7 +114,10 @@ ignore_missing_imports = True
 # no Warning level messages displayed, use "--disable=all --enable=classes
 # --disable=W".
 disable=consider-using-f-string,
+        consider-using-with,
+        too-many-arguments,
         too-many-function-args,  # mypy handles this with less false positives.
+        too-many-instance-attributes,
         no-member,  # mypy also handles this better.
 
 [pylint.basic]