python: idl: Allow retry even when using a single remote.

As described in commit [1], it's possible that remote IP is backed by
a load-balancer and re-connection to this same IP will lead to
connection to a different server.  This case is supported for C version
of IDL and should be supported in a same way for python implementation.

[1] ca367fa ("ovsdb-idl.c: Allows retry even when using a single remote.")

Signed-off-by: Ilya Maximets <i.maximets@ovn.org>
Acked-by: Dumitru Ceara <dceara@redhat.com>

python/ovs/db/idl.py

@@ -777,8 +777,7 @@ def __check_server_db(self):
                       % (session_name, self._db.name))
             return False
 
-        if (database.model == CLUSTERED and
-            self._session.get_num_of_remotes() > 1):
+        if database.model == CLUSTERED:
             if not database.schema:
                 vlog.info('%s: clustered database server has not yet joined '
                           'cluster; trying another server' % session_name)

tests/ovsdb-cluster.at

@@ -119,17 +119,26 @@ ovsdb_test_cluster_disconnect () {
     # Connect to $target.  Use "wait" to trigger a non-op transaction so
     # that test-ovsdb will not quit.
 
-    test-ovsdb '-vPATTERN:console:test-ovsdb|%c|%m' -v -t10 idl unix:s$target.ovsdb '[["idltest",
+    txn='[["idltest",
           {"op": "wait",
            "table": "simple",
            "where": [["i", "==", 1]],
            "columns": ["i"],
            "until": "==",
-           "rows": [{"i": 1}]}]]' > test-ovsdb.log 2>&1 &
+           "rows": [{"i": 1}]}]]'
+
+    test-ovsdb '-vPATTERN:console:test-ovsdb|%c|%m' -v -t10 idl \
+               unix:s$target.ovsdb "$txn" > test-ovsdb.log 2>&1 &
     echo $! > test-ovsdb.pid
 
     OVS_WAIT_UNTIL([grep "000: table simple: i=1" test-ovsdb.log])
 
+    $PYTHON3 $srcdir/test-ovsdb.py -t10 idl $abs_srcdir/idltest.ovsschema \
+               unix:s$target.ovsdb "$txn" > test-ovsdb-py.log 2>&1 &
+    echo $! > test-ovsdb-py.pid
+
+    OVS_WAIT_UNTIL([grep "000: table simple: i=1" test-ovsdb-py.log])
+
     # Start collecting raft_is_connected logs for $target before shutting down
     # any servers.
     tail -f s$target.log > raft_is_connected.log &
@@ -142,6 +151,7 @@ ovsdb_test_cluster_disconnect () {
 
     # The test-ovsdb should detect the disconnect and retry.
     OVS_WAIT_UNTIL([grep disconnect test-ovsdb.log])
+    OVS_WAIT_UNTIL([grep disconnect test-ovsdb-py.log])
 
     # The $target debug log should show raft_is_connected: false.
     OVS_WAIT_UNTIL([grep "raft_is_connected: false" raft_is_connected.log])

tests/test-ovsdb.py

@@ -651,7 +651,7 @@ def do_idl(schema_file, remote, *commands):
         commands = commands[1:]
     else:
         schema_helper.register_all()
-    idl = ovs.db.idl.Idl(remote, schema_helper)
+    idl = ovs.db.idl.Idl(remote, schema_helper, leader_only=False)
     if "simple3" in idl.tables:
         idl.index_create("simple3", "simple3_by_name")