// TestKVClientPrepareAndFlush prepares a sequence of increment
// calls and then flushes them and verifies the results.
func TestKVClientPrepareAndFlush(t *testing.T) {
s := StartTestServer(t)
defer s.Stop()
kvClient := createTestClient(s.HTTPAddr)
kvClient.User = storage.UserRoot
replies := []*proto.IncrementResponse{}
keys := []proto.Key{}
for i := 0; i < 10; i++ {
key := proto.Key(fmt.Sprintf("key %02d", i))
keys = append(keys, key)
reply := &proto.IncrementResponse{}
replies = append(replies, reply)
kvClient.Prepare(proto.Increment, proto.IncrementArgs(key, int64(i)), reply)
}
if err := kvClient.Flush(); err != nil {
t.Fatal(err)
}
for i, reply := range replies {
if reply.NewValue != int64(i) {
t.Errorf("%d: expected %d; got %d", i, i, reply.NewValue)
}
}
// Now try 2 scans.
scan1 := &proto.ScanResponse{}
scan2 := &proto.ScanResponse{}
kvClient.Prepare(proto.Scan, proto.ScanArgs(proto.Key("key 00"), proto.Key("key 05"), 0), scan1)
kvClient.Prepare(proto.Scan, proto.ScanArgs(proto.Key("key 05"), proto.Key("key 10"), 0), scan2)
if err := kvClient.Flush(); err != nil {
t.Fatal(err)
}
if len(scan1.Rows) != 5 || len(scan2.Rows) != 5 {
t.Errorf("expected scan results to include 5 and 5 rows; got %d and %d",
len(scan1.Rows), len(scan2.Rows))
}
for i := 0; i < 5; i++ {
if key := scan1.Rows[i].Key; !key.Equal(keys[i]) {
t.Errorf("expected scan1 key %d to be %q; got %q", i, keys[i], key)
}
if val := scan1.Rows[i].Value.GetInteger(); val != int64(i) {
t.Errorf("expected scan1 result %d to be %d; got %d", i, i, val)
}
if key := scan2.Rows[i].Key; !key.Equal(keys[i+5]) {
t.Errorf("expected scan2 key %d to be %q; got %q", i, keys[i+5], key)
}
if val := scan2.Rows[i].Value.GetInteger(); val != int64(i+5) {
t.Errorf("expected scan2 result %d to be %d; got %d", i, i+5, val)
}
}
}
// concurrentIncrements starts two Goroutines in parallel, both of which
// read the integers stored at the other's key and add it onto their own.
// It is checked that the outcome is serializable, i.e. exactly one of the
// two Goroutines (the later write) sees the previous write by the other.
func concurrentIncrements(kvClient *client.KV, t *testing.T) {
// wgStart waits for all transactions to line up, wgEnd has the main
// function wait for them to finish.
var wgStart, wgEnd sync.WaitGroup
wgStart.Add(2 + 1)
wgEnd.Add(2)
for i := 0; i < 2; i++ {
go func(i int) {
// Read the other key, write key i.
readKey := []byte(fmt.Sprintf("value-%d", (i+1)%2))
writeKey := []byte(fmt.Sprintf("value-%d", i))
defer wgEnd.Done()
wgStart.Done()
// Wait until the other goroutines are running.
wgStart.Wait()
txnOpts := &client.TransactionOptions{
Name: fmt.Sprintf("test-%d", i),
}
if err := kvClient.RunTransaction(txnOpts, func(txn *client.KV) error {
// Retrieve the other key.
gr := &proto.GetResponse{}
if err := txn.Call(proto.Get, proto.GetArgs(readKey), gr); err != nil {
return err
}
otherValue := int64(0)
if gr.Value != nil && gr.Value.Integer != nil {
otherValue = *gr.Value.Integer
}
pr := &proto.IncrementResponse{}
pa := proto.IncrementArgs(writeKey, 1+otherValue)
if err := txn.Call(proto.Increment, pa, pr); err != nil {
return err
}
return nil
}); err != nil {
t.Error(err)
}
}(i)
}
// Kick the goroutines loose.
wgStart.Done()
// Wait for the goroutines to finish.
wgEnd.Wait()
// Verify that both keys contain something and, more importantly, that
// one key actually contains the value of the first writer and not only
// its own.
total := int64(0)
results := []int64(nil)
for i := 0; i < 2; i++ {
readKey := []byte(fmt.Sprintf("value-%d", i))
gr := &proto.GetResponse{}
if err := kvClient.Call(proto.Get, proto.GetArgs(readKey), gr); err != nil {
log.Fatal(err)
}
if gr.Value == nil || gr.Value.Integer == nil {
t.Fatalf("unexpected empty key: %v=%v", readKey, gr.Value)
}
total += *gr.Value.Integer
results = append(results, *gr.Value.Integer)
}
// First writer should have 1, second one 2
if total != 3 {
t.Fatalf("got unserializable values %v", results)
}
}