// waitForInitialValue waits for the initial value of
// /keyspaces/test_keyspace/SrvKeyspace to appear, and match the
// provided srvKeyspace.
func waitForInitialValue(t *testing.T, ts topo.Impl, cell string, srvKeyspace *topodatapb.SrvKeyspace) (changes <-chan *topo.WatchData, cancel func()) {
var current *topo.WatchData
ctx := context.Background()
start := time.Now()
for {
current, changes, cancel = ts.Watch(ctx, cell, "/keyspaces/test_keyspace/SrvKeyspace")
if current.Err == topo.ErrNoNode {
// hasn't appeared yet
if time.Now().Sub(start) > 10*time.Second {
t.Fatalf("time out waiting for file to appear")
}
time.Sleep(10 * time.Millisecond)
continue
}
if current.Err != nil {
t.Fatalf("watch failed: %v", current.Err)
}
// we got a valid result
break
}
got := &topodatapb.SrvKeyspace{}
if err := proto.Unmarshal(current.Contents, got); err != nil {
t.Fatalf("cannot proto-unmarshal data: %v", err)
}
if !proto.Equal(got, srvKeyspace) {
t.Fatalf("got bad data: %v expected: %v", got, srvKeyspace)
}
return changes, cancel
}
// checkWatch runs the tests on the Watch part of the Backend API.
// We can't just use the full API yet, so use SrvKeyspace for now.
func checkWatch(t *testing.T, ts topo.Impl) {
ctx := context.Background()
cell := getLocalCell(ctx, t, ts)
// start watching something that doesn't exist -> error
current, changes, cancel := ts.Watch(ctx, cell, "/keyspaces/test_keyspace/SrvKeyspace")
if current.Err != topo.ErrNoNode {
t.Errorf("watch on missing node didn't return ErrNoNode: %v %v", current, changes)
}
// create some data
srvKeyspace := &topodatapb.SrvKeyspace{
ShardingColumnName: "user_id",
}
if err := ts.UpdateSrvKeyspace(ctx, cell, "test_keyspace", srvKeyspace); err != nil {
t.Fatalf("UpdateSrvKeyspace(1): %v", err)
}
// start watching again, it should work
changes, cancel = waitForInitialValue(t, ts, cell, srvKeyspace)
defer cancel()
// change the data
srvKeyspace.ShardingColumnName = "new_user_id"
if err := ts.UpdateSrvKeyspace(ctx, cell, "test_keyspace", srvKeyspace); err != nil {
t.Fatalf("UpdateSrvKeyspace(2): %v", err)
}
// Make sure we get the watch data, maybe not as first notice,
// but eventually. The API specifies it is possible to get duplicate
// notifications.
for {
wd, ok := <-changes
if !ok {
t.Fatalf("watch channel unexpectedly closed")
}
if wd.Err != nil {
t.Fatalf("watch interrupted: %v", wd.Err)
}
got := &topodatapb.SrvKeyspace{}
if err := proto.Unmarshal(wd.Contents, got); err != nil {
t.Fatalf("cannot proto-unmarshal data: %v", err)
}
if got.ShardingColumnName == "user_id" {
// extra first value, still good
continue
}
if got.ShardingColumnName == "new_user_id" {
// watch worked, good
break
}
t.Fatalf("got unknown SrvKeyspace: %v", got)
}
// remove the SrvKeyspace
if err := ts.DeleteSrvKeyspace(ctx, cell, "test_keyspace"); err != nil {
t.Fatalf("DeleteSrvKeyspace: %v", err)
}
// Make sure we get the ErrNoNode notification eventually.
// The API specifies it is possible to get duplicate
// notifications.
for {
wd, ok := <-changes
if !ok {
t.Fatalf("watch channel unexpectedly closed")
}
if wd.Err == topo.ErrNoNode {
// good
break
}
if wd.Err != nil {
t.Fatalf("bad error returned for deletion: %v", wd.Err)
}
// we got something, better be the right value
got := &topodatapb.SrvKeyspace{}
if err := proto.Unmarshal(wd.Contents, got); err != nil {
t.Fatalf("cannot proto-unmarshal data: %v", err)
}
if got.ShardingColumnName == "new_user_id" {
// good value
continue
}
t.Fatalf("got unknown SrvKeyspace waiting for deletion: %v", got)
}
// now the channel should be closed
if wd, ok := <-changes; ok {
t.Fatalf("got unexpected event after error: %v", wd)
}
}