Re: [ovirt-devel] [VDSM][JSON RPC] new vdsClient?

21 Nov 2014


      ----- Original Message -----
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From: "Dan Kenigsberg" <danken@redhat.com>
To: "Nir Soffer" <nsoffer@redhat.com>
Cc: "Piotr Kliczewski" <piotr.kliczewski@gmail.com>, devel@ovirt.org
Sent: Wednesday, November 19, 2014 7:21:09 PM
Subject: Re: [ovirt-devel] [VDSM][JSON RPC] new vdsClient?
On Fri, Nov 14, 2014 at 04:24:17PM -0500, Nir Soffer wrote:
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Hi everyone,
the recent JSONRPC discussion and my last work around vdsClient
reminded
me
that
since a long time there it was vague plans for a vdsClient overhaul
or at least I haven't ever found a detailed plan :)
Since we have to add jsonrpc support anyway, it could be a good chance
to
bootstrap
a new vdsClient, and incrementally enhance it as needs arises; the old
vdsClient will
not go away very soon, I guess.
At least, we can to put together a wishlist for a new vdsClient and
add it
to
the wiki.
My one, so far:
* client library package: we should have a program-friendly python
package
to
access
  VDSM, in order
* JSON for input: I's like to open logs, grab a line including a
command
and
feed
  vdsClient with the very same line
Currently we don't see commands json input in the logs, but this can be
a
good
idea (in debug mode).
+1
JSON for output: current vdsClient format replies in a mix of text and
json. We
need to print the json returned from vdsm as is.
but a pretty-printed output can be useful, too.
Actually it is more useful.
...
...
I started a simple jsonrpc client that can be used for testing *now*:
http://gerrit.ovirt.org/35181
Example usage:
Calling method without arguements:
# jsonrpc Host.getVMList
  {
      "jsonrpc": "2.0",
      "id": "0e043d83-294a-4d31-b1b6-6dc2f2747494",
      "result": [
          "b3f6fa00-b315-4ad4-8108-f73da817b5c5"
      ]
  }
Calling method with arguements:
# jsonrpc VM.getStats '{"vmID": "b3f6fa00-b315-4ad4-8108-f73da817b5c5"}'
  {
      "jsonrpc": "2.0",
      "id": "cefd25a3-6250-4123-8a56-d7047899e19e",
      "result": [
          {
              "status": "Down",
              "exitMessage": "Admin shut down from the engine",
              "vmId": "b3f6fa00-b315-4ad4-8108-f73da817b5c5",
              "exitReason": 6,
              "timeOffset": "0",
              "exitCode": 0
          }
      ]
  }
Thanks, this looks very nice and ready for contrib, imho.
I'd love to see something similar done to make vdscli connect over
jsonrpc. When I need to do something less than trivial from the command
line, I start python and
from vdsm import vdscli
    s = vdscli.connect() # does a horribly useful heuristic, to connect
                         # to local host over xmlrpc
Maybe:

    s = vdscli.connect("jsonrpc:10.35.0.174:54321")
...
print s.getVMList()
Nice - but we have mismatch between the API (used by jsonrpc) and xmlrpc verbs.
...
I'd like to see vdscli.connect() extended to jsonrpc. This would
simplify
    Bug 1112594 - Use jsonrpc during migration of vms
too.
Nir