python: Allow tuning the session probe_interval from IDL

This patch is adding a new parameter called "probe_interval" to the
constructor of the Idl class. This new parameter will be used to tune
the database connection probing for that IDL session, some users might
want to tune it to be less agressive than the current 5s default in OVS
or even disable it.

Reported-at: https://bugs.launchpad.net/networking-ovn/+bug/1680146
Signed-off-by: Lucas Alvares Gomes <lucasagomes@gmail.com>
Acked-by: Daniel Alvarez <dalvarez@redhat.com>
Signed-off-by: Russell Bryant <russell@ovn.org>

python/ovs/jsonrpc.py

@@ -376,7 +376,7 @@ class Session(object):
         self.seqno = 0
 
     @staticmethod
-    def open(name):
+    def open(name, probe_interval=None):
         """Creates and returns a Session that maintains a JSON-RPC session to
         'name', which should be a string acceptable to ovs.stream.Stream or
         ovs.stream.PassiveStream's initializer.
@@ -387,7 +387,12 @@ class Session(object):
         If 'name' is a passive connection method, e.g. "ptcp:", the new session
         listens for connections to 'name'.  It maintains at most one connection
         at any given time.  Any new connection causes the previous one (if any)
-        to be dropped."""
+        to be dropped.
+
+        If "probe_interval" is zero it disables the connection keepalive
+        feature. If non-zero the value will be forced to at least 1000
+        milliseconds. If None it will just use the default value in OVS.
+        """
         reconnect = ovs.reconnect.Reconnect(ovs.timeval.msec())
         reconnect.set_name(name)
         reconnect.enable(ovs.timeval.msec())
@@ -397,6 +402,8 @@ class Session(object):
 
         if not ovs.stream.stream_or_pstream_needs_probes(name):
             reconnect.set_probe_interval(0)
+        elif probe_interval is not None:
+            reconnect.set_probe_interval(probe_interval)
 
         return Session(reconnect, None)