tests: Wait for new ovn-controllers to connect to Southbound.

Simulated chassis are added with ovn_attach(), ovn_az_attach() and
start_virtual_controller().  Wait for ovn-controllers to register in the
Southbound (create their Encap record) before continuing.  That's
required because 'ovn-nbctl --wait=hv sync' (used throughout the test
suite) has different semantics if no chassis is registered in the
Southbound.  In those cases the command is equivalent to 'ovn-nbctl
--wait=sb sync'.

This was causing a race condition due to which CI would occasionally
fail because of missing OpenFlows, e.g.:
https://github.com/ovsrobot/ovn/actions/runs/6471719045/job/17570941948#step:8:4849

Co-authored-by: Xavier Simonart <xsimonar@redhat.com>
Signed-off-by: Xavier Simonart <xsimonar@redhat.com>
Signed-off-by: Dumitru Ceara <dceara@redhat.com>
Signed-off-by: 0-day Robot <robot@bytheb.org>

tests/ovn-macros.at

@@ -288,6 +288,25 @@ net_attach () {
         || return 1
 }
 
+ovn_wait_for_encaps() {
+    local systemid=$1
+
+    local encap=$(ovs-vsctl get Open_vSwitch . external_ids:ovn-encap-type-$systemid)
+    if [[ -n "$encap" ]]; then
+        encap=$(ovs-vsctl get Open_vSwitch .external_ids:ovn-encap-type)
+    fi
+
+    local ip=$(ovs-vsctl get Open_vSwitch . external_ids:ovn-encap-ip-$systemid)
+    if [[ -n "$ip" ]]; then
+        ip=$(ovs-vsctl get Open_vSwitch .external_ids:ovn-encap-ip)
+    fi
+
+    IFS="," read -r -a encap_types <<< "$encap"
+    for e in "${encap_types[[@]]}"; do
+        wait_column "$ip" sb:Encap ip chassis_name="$systemid" type="$e"
+    done
+}
+
 # ovn_az_attach AZ NETWORK BRIDGE IP [MASKLEN] [ENCAP]
 ovn_az_attach() {
     local az=$1 net=$2 bridge=$3 ip=$4 masklen=${5-24} encap=${6-geneve,vxlan} systemid=${7-$sandbox} cli_args=${@:8}
@@ -332,6 +351,11 @@ ovn_az_attach() {
     fi
 
     start_daemon ovn-controller --enable-dummy-vif-plug ${cli_args} || return 1
+    if test X"$az" = XNONE; then
+        ovn_wait_for_encaps $systemid
+    else
+        ovn_as $az ovn_wait_for_encaps $systemid
+    fi
 }
 
 # ovn_attach NETWORK BRIDGE IP [MASKLEN] [ENCAP]
@@ -372,6 +396,7 @@ start_virtual_controller() {
         || return 1
 
     ovn-controller --enable-dummy-vif-plug ${cli_args} -vconsole:off --detach --no-chdir
+    ovn_wait_for_encaps $systemid
 }
 
 # ovn_setenv AZ