// LoadVSchema loads the VSchema from the topo. The function does
// not return an error. It instead logs warnings on failure.
func (plr *Planner) LoadVSchema(ctx context.Context) {
formal := &vindexes.VSchemaFormal{
Keyspaces: make(map[string]vindexes.KeyspaceFormal),
}
keyspaces, err := plr.serv.GetSrvKeyspaceNames(ctx, plr.cell)
if err != nil {
log.Warningf("Error loading vschema: could not read keyspaces: %v", err)
return
}
for _, keyspace := range keyspaces {
formal.Keyspaces[keyspace] = vindexes.KeyspaceFormal{}
kschema, err := plr.serv.GetVSchema(context.TODO(), keyspace)
if err != nil {
log.Warningf("Error loading vschema for keyspace: %s: %v", keyspace, err)
continue
}
var kformal vindexes.KeyspaceFormal
err = json.Unmarshal([]byte(kschema), &kformal)
if err != nil {
log.Warningf("Error unmarshalling vschema for keyspace: %s: %v", keyspace, err)
continue
}
formal.Keyspaces[keyspace] = kformal
}
vschema, err := vindexes.BuildVSchema(formal)
if err != nil {
log.Warningf("Error creating VSchema: %v", err)
return
}
plr.mu.Lock()
plr.vschema = vschema
plr.mu.Unlock()
}
func loadSchema(t *testing.T, filename string) *vindexes.VSchema {
formal, err := vindexes.LoadFormal(locateFile(filename))
if err != nil {
t.Fatal(err)
}
vschema, err := vindexes.BuildVSchema(formal)
if err != nil {
t.Fatal(err)
}
return vschema
}
// WatchSrvVSchema watches the SrvVSchema from the topo. The function does
// not return an error. It instead logs warnings on failure.
// The SrvVSchema object is roll-up of all the Keyspace information,
// so when a keyspace is added or removed, it will be properly updated.
//
// This function will wait until the first value has either been processed
// or triggered an error before returning.
func (plr *Planner) WatchSrvVSchema(ctx context.Context, cell string) {
wg := sync.WaitGroup{}
wg.Add(1)
go func() {
foundFirstValue := false
// Create a closure to save the vschema. If the value
// passed is nil, it means we encountered an error and
// we don't know the real value. In this case, we want
// to use the previous value if it was set, or an
// empty vschema if it wasn't.
saveVSchema := func(v *vschemapb.SrvVSchema, errorMessage string) {
// transform the provided SrvVSchema into a VSchema
var vschema *vindexes.VSchema
if v != nil {
var err error
vschema, err = vindexes.BuildVSchema(v)
if err != nil {
log.Warningf("Error creating VSchema for cell %v (will try again next update): %v", cell, err)
v = nil
errorMessage = fmt.Sprintf("Error creating VSchema for cell %v: %v", cell, err)
if vschemaCounters != nil {
vschemaCounters.Add("Parsing", 1)
}
}
}
if v == nil {
// we encountered an error, build an
// empty vschema
vschema, _ = vindexes.BuildVSchema(&vschemapb.SrvVSchema{})
}
// Build the display version.
stats := NewVSchemaStats(vschema, errorMessage)
// save our value
plr.mu.Lock()
if v != nil {
// no errors, we can save our schema
plr.vschema = vschema
} else {
// we had an error, use the empty vschema
// if we had nothing before.
if plr.vschema == nil {
plr.vschema = vschema
}
}
plr.vschemaStats = stats
plr.mu.Unlock()
plr.plans.Clear()
if vschemaCounters != nil {
vschemaCounters.Add("Reload", 1)
}
// notify the listener
if !foundFirstValue {
foundFirstValue = true
wg.Done()
}
}
for {
current, changes, _ := plr.serv.WatchSrvVSchema(ctx, cell)
if current.Err != nil {
// Don't log if there is no VSchema to start with.
if current.Err != topo.ErrNoNode {
log.Warningf("Error watching vschema for cell %s (will wait 5s before retrying): %v", cell, current.Err)
}
saveVSchema(nil, fmt.Sprintf("Error watching SvrVSchema: %v", current.Err.Error()))
if vschemaCounters != nil {
vschemaCounters.Add("WatchError", 1)
}
time.Sleep(5 * time.Second)
continue
}
saveVSchema(current.Value, "")
for c := range changes {
if c.Err != nil {
// If the SrvVschema disappears, we need to clear our record.
// Otherwise, keep what we already had before.
if c.Err == topo.ErrNoNode {
saveVSchema(nil, "SrvVSchema object was removed from topology.")
}
log.Warningf("Error while watching vschema for cell %s (will wait 5s before retrying): %v", cell, c.Err)
if vschemaCounters != nil {
vschemaCounters.Add("WatchError", 1)
}
break
}
saveVSchema(c.Value, "")
}
// Sleep a bit before trying again.
time.Sleep(5 * time.Second)
}
}()
// wait for the first value to have been processed
wg.Wait()
}
// WatchSrvVSchema watches the SrvVSchema from the topo. The function does
// not return an error. It instead logs warnings on failure.
// The SrvVSchema object is roll-up of all the Keyspace information,
// so when a keyspace is added or removed, it will be properly updated.
//
// This function will wait until the first value has either been processed
// or triggered an error before returning.
func (plr *Planner) WatchSrvVSchema(ctx context.Context, cell string) {
wg := sync.WaitGroup{}
wg.Add(1)
go func() {
foundFirstValue := false
// Create a closure to save the vschema. If the value
// passed is nil, it means we encountered an error and
// we don't know the real value. In this case, we want
// to use the previous value if it was set, or an
// empty vschema if it wasn't.
saveVSchema := func(v *vschemapb.SrvVSchema) {
// transform the provided SrvVSchema into a VSchema
var vschema *vindexes.VSchema
if v != nil {
var err error
vschema, err = vindexes.BuildVSchema(v)
if err != nil {
log.Warningf("Error creating VSchema for cell %v (will try again next update): %v", cell, err)
v = nil
}
}
if v == nil {
// we encountered an error, build an
// empty vschema
vschema, _ = vindexes.BuildVSchema(&vschemapb.SrvVSchema{})
}
// save our value
plr.mu.Lock()
if v != nil {
// no errors, we can save our schema
plr.vschema = vschema
} else {
// we had an error, use the empty vschema
// if we had nothing before.
if plr.vschema == nil {
plr.vschema = vschema
}
}
plr.mu.Unlock()
plr.plans.Clear()
// notify the listener
if !foundFirstValue {
foundFirstValue = true
wg.Done()
}
}
for {
n, err := plr.serv.WatchSrvVSchema(ctx, cell)
if err != nil {
log.Warningf("Error watching vschema for cell %s (will wait 5s before retrying): %v", cell, err)
saveVSchema(nil)
time.Sleep(5 * time.Second)
continue
}
for value := range n {
if value == nil {
log.Warningf("Got an empty vschema for cell %v", cell)
saveVSchema(&vschemapb.SrvVSchema{})
continue
}
saveVSchema(value)
}
log.Warningf("Watch on vschema for cell %v ended, will wait 5s before retrying", cell)
saveVSchema(nil)
time.Sleep(5 * time.Second)
}
}()
// wait for the first value to have been processed
wg.Wait()
}
