// LockShard will lock the shard in the topology server.
// UnlockShard should be called if this returns no error.
func (n *ActionNode) LockShard(ctx context.Context, ts topo.Server, keyspace, shard string) (lockPath string, err error) {
log.Infof("Locking shard %v/%v for action %v", keyspace, shard, n.Action)
span := trace.NewSpanFromContext(ctx)
span.StartClient("TopoServer.LockShardForAction")
span.Annotate("action", n.Action)
span.Annotate("keyspace", keyspace)
span.Annotate("shard", shard)
defer span.Finish()
return ts.LockShardForAction(ctx, keyspace, shard, n.ToJSON())
}
// LockShard will lock the shard in the topology server.
// UnlockShard should be called if this returns no error.
func (n *ActionNode) LockShard(ctx context.Context, ts topo.Server, keyspace, shard string) (lockPath string, err error) {
log.Infof("Locking shard %v/%v for action %v", keyspace, shard, n.Action)
ctx, cancel := context.WithTimeout(ctx, *LockTimeout)
defer cancel()
span := trace.NewSpanFromContext(ctx)
span.StartClient("TopoServer.LockShardForAction")
span.Annotate("action", n.Action)
span.Annotate("keyspace", keyspace)
span.Annotate("shard", shard)
defer span.Finish()
j, err := n.ToJSON()
if err != nil {
return "", err
}
return ts.LockShardForAction(ctx, keyspace, shard, j)
}
// checkShardLockUnblocks makes sure that a routine waiting on a lock
// is unblocked when another routine frees the lock
func checkShardLockUnblocks(ctx context.Context, t *testing.T, ts topo.Server) {
unblock := make(chan struct{})
finished := make(chan struct{})
// as soon as we're unblocked, we try to lock the shard
go func() {
<-unblock
lockPath, err := ts.LockShardForAction(ctx, "test_keyspace", "10-20", "fake-content")
if err != nil {
t.Fatalf("LockShardForAction(test_keyspace, 10-20) failed: %v", err)
}
if err = ts.UnlockShardForAction(ctx, "test_keyspace", "10-20", lockPath, "fake-results"); err != nil {
t.Fatalf("UnlockShardForAction(test_keyspace, 10-20): %v", err)
}
close(finished)
}()
// lock the shard
lockPath2, err := ts.LockShardForAction(ctx, "test_keyspace", "10-20", "fake-content")
if err != nil {
t.Fatalf("LockShardForAction(test_keyspace, 10-20) failed: %v", err)
}
// unblock the go routine so it starts waiting
close(unblock)
// sleep for a while so we're sure the go routine is blocking
time.Sleep(timeUntilLockIsTaken)
if err = ts.UnlockShardForAction(ctx, "test_keyspace", "10-20", lockPath2, "fake-results"); err != nil {
t.Fatalf("UnlockShardForAction(test_keyspace, 10-20): %v", err)
}
timeout := time.After(10 * time.Second)
select {
case <-finished:
case <-timeout:
t.Fatalf("unlocking timed out")
}
}
func checkShardLockTimeout(ctx context.Context, t *testing.T, ts topo.Server) {
lockPath, err := ts.LockShardForAction(ctx, "test_keyspace", "10-20", "fake-content")
if err != nil {
t.Fatalf("LockShardForAction: %v", err)
}
// test we can't take the lock again
fastCtx, cancel := context.WithTimeout(ctx, timeUntilLockIsTaken)
if _, err := ts.LockShardForAction(fastCtx, "test_keyspace", "10-20", "unused-fake-content"); err != topo.ErrTimeout {
t.Fatalf("LockShardForAction(again): %v", err)
}
cancel()
// test we can interrupt taking the lock
interruptCtx, cancel := context.WithCancel(ctx)
go func() {
time.Sleep(timeUntilLockIsTaken)
cancel()
}()
if _, err := ts.LockShardForAction(interruptCtx, "test_keyspace", "10-20", "unused-fake-content"); err != topo.ErrInterrupted {
t.Fatalf("LockShardForAction(interrupted): %v", err)
}
if err := ts.UnlockShardForAction(ctx, "test_keyspace", "10-20", lockPath, "fake-results"); err != nil {
t.Fatalf("UnlockShardForAction(): %v", err)
}
// test we can't unlock again
if err := ts.UnlockShardForAction(ctx, "test_keyspace", "10-20", lockPath, "fake-results"); err == nil {
t.Error("UnlockShardForAction(again) worked")
}
}
func CheckShardLock(t *testing.T, ts topo.Server) {
if err := ts.CreateKeyspace("test_keyspace", &topo.Keyspace{}); err != nil {
t.Fatalf("CreateKeyspace: %v", err)
}
if err := topo.CreateShard(ts, "test_keyspace", "10-20"); err != nil {
t.Fatalf("CreateShard: %v", err)
}
interrupted := make(chan struct{}, 1)
lockPath, err := ts.LockShardForAction("test_keyspace", "10-20", "fake-content", 5*time.Second, interrupted)
if err != nil {
t.Fatalf("LockShardForAction: %v", err)
}
// test we can't take the lock again
if _, err := ts.LockShardForAction("test_keyspace", "10-20", "unused-fake-content", time.Second/2, interrupted); err != topo.ErrTimeout {
t.Errorf("LockShardForAction(again): %v", err)
}
// test we can interrupt taking the lock
go func() {
time.Sleep(time.Second / 2)
close(interrupted)
}()
if _, err := ts.LockShardForAction("test_keyspace", "10-20", "unused-fake-content", 5*time.Second, interrupted); err != topo.ErrInterrupted {
t.Errorf("LockShardForAction(interrupted): %v", err)
}
if err := ts.UnlockShardForAction("test_keyspace", "10-20", lockPath, "fake-results"); err != nil {
t.Errorf("UnlockShardForAction(): %v", err)
}
// test we can't unlock again
if err := ts.UnlockShardForAction("test_keyspace", "10-20", lockPath, "fake-results"); err == nil {
t.Error("UnlockShardForAction(again) worked")
}
// test we can't lock a non-existing shard
interrupted = make(chan struct{}, 1)
if _, err := ts.LockShardForAction("test_keyspace", "20-30", "fake-content", 5*time.Second, interrupted); err == nil {
t.Fatalf("LockShardForAction(test_keyspace/20-30) worked for non-existing shard")
}
}
func checkShardLockMissing(ctx context.Context, t *testing.T, ts topo.Server) {
// test we can't lock a non-existing shard
if _, err := ts.LockShardForAction(ctx, "test_keyspace", "20-30", "fake-content"); err == nil {
t.Fatalf("LockShardForAction(test_keyspace/20-30) worked for non-existing shard")
}
}
// LockShard will lock the shard in the topology server.
// UnlockShard should be called if this returns no error.
func (n *ActionNode) LockShard(ts topo.Server, keyspace, shard string, lockTimeout time.Duration, interrupted chan struct{}) (lockPath string, err error) {
log.Infof("Locking shard %v/%v for action %v", keyspace, shard, n.Action)
return ts.LockShardForAction(keyspace, shard, n.ToJson(), lockTimeout, interrupted)
}