// LockSrvShard will lock the serving shard in the topology server.
// UnlockSrvShard should be called if this returns no error.
func (n *ActionNode) LockSrvShard(ctx context.Context, ts topo.Server, cell, keyspace, shard string) (lockPath string, err error) {
log.Infof("Locking serving shard %v/%v/%v for action %v", cell, keyspace, shard, n.Action)
span := trace.NewSpanFromContext(ctx)
span.StartClient("TopoServer.LockSrvShardForAction")
span.Annotate("action", n.Action)
span.Annotate("keyspace", keyspace)
span.Annotate("shard", shard)
span.Annotate("cell", cell)
defer span.Finish()
return ts.LockSrvShardForAction(ctx, cell, keyspace, shard, n.ToJSON())
}
// checkSrvShardLockUnblocks makes sure that a routine waiting on a lock
// is unblocked when another routine frees the lock
func checkSrvShardLockUnblocks(ctx context.Context, t *testing.T, ts topo.Server) {
cell := getLocalCell(ctx, t, ts)
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.LockSrvShardForAction(ctx, cell, "test_keyspace", "10-20", "fake-content")
if err != nil {
t.Fatalf("LockSrvShardForAction(test, test_keyspace, 10-20) failed: %v", err)
}
if err = ts.UnlockSrvShardForAction(ctx, cell, "test_keyspace", "10-20", lockPath, "fake-results"); err != nil {
t.Fatalf("UnlockSrvShardForAction(test, test_keyspace, 10-20): %v", err)
}
close(finished)
}()
// lock the shard
lockPath2, err := ts.LockSrvShardForAction(ctx, cell, "test_keyspace", "10-20", "fake-content")
if err != nil {
t.Fatalf("LockSrvShardForAction(test, 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.UnlockSrvShardForAction(ctx, cell, "test_keyspace", "10-20", lockPath2, "fake-results"); err != nil {
t.Fatalf("UnlockSrvShardForAction(test, test_keyspace, 10-20): %v", err)
}
timeout := time.After(10 * time.Second)
select {
case <-finished:
case <-timeout:
t.Fatalf("unlocking timed out")
}
}
func checkSrvShardLockGeneral(ctx context.Context, t *testing.T, ts topo.Server) {
cell := getLocalCell(ctx, t, ts)
// make sure we can create the lock even if no directory exists
lockPath, err := ts.LockSrvShardForAction(ctx, cell, "test_keyspace", "10-20", "fake-content")
if err != nil {
t.Fatalf("LockSrvShardForAction: %v", err)
}
if err := ts.UnlockSrvShardForAction(ctx, cell, "test_keyspace", "10-20", lockPath, "fake-results"); err != nil {
t.Fatalf("UnlockShardForAction: %v", err)
}
// now take the lock again after the root exists
lockPath, err = ts.LockSrvShardForAction(ctx, cell, "test_keyspace", "10-20", "fake-content")
if err != nil {
t.Fatalf("LockSrvShardForAction: %v", err)
}
// test we can't take the lock again
fastCtx, cancel := context.WithTimeout(ctx, timeUntilLockIsTaken)
if _, err := ts.LockSrvShardForAction(fastCtx, cell, "test_keyspace", "10-20", "unused-fake-content"); err != topo.ErrTimeout {
t.Fatalf("LockSrvShardForAction(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.LockSrvShardForAction(interruptCtx, cell, "test_keyspace", "10-20", "unused-fake-content"); err != topo.ErrInterrupted {
t.Fatalf("LockSrvShardForAction(interrupted): %v", err)
}
// unlock now
if err := ts.UnlockSrvShardForAction(ctx, cell, "test_keyspace", "10-20", lockPath, "fake-results"); err != nil {
t.Fatalf("UnlockSrvShardForAction(): %v", err)
}
// test we can't unlock again
if err := ts.UnlockSrvShardForAction(ctx, cell, "test_keyspace", "10-20", lockPath, "fake-results"); err == nil {
t.Error("UnlockSrvShardForAction(again) worked")
}
}
func CheckSrvShardLock(t *testing.T, ts topo.Server) {
// make sure we can create the lock even if no directory exists
interrupted := make(chan struct{}, 1)
lockPath, err := ts.LockSrvShardForAction("test", "test_keyspace", "10-20", "fake-content", 5*time.Second, interrupted)
if err != nil {
t.Fatalf("LockSrvShardForAction: %v", err)
}
if err := ts.UnlockSrvShardForAction("test", "test_keyspace", "10-20", lockPath, "fake-results"); err != nil {
t.Errorf("UnlockShardForAction(): %v", err)
}
// now take the lock again after the root exists
lockPath, err = ts.LockSrvShardForAction("test", "test_keyspace", "10-20", "fake-content", 5*time.Second, interrupted)
if err != nil {
t.Fatalf("LockSrvShardForAction: %v", err)
}
// test we can't take the lock again
if _, err := ts.LockSrvShardForAction("test", "test_keyspace", "10-20", "unused-fake-content", time.Second/2, interrupted); err != topo.ErrTimeout {
t.Errorf("LockSrvShardForAction(again): %v", err)
}
// test we can interrupt taking the lock
go func() {
time.Sleep(time.Second / 2)
close(interrupted)
}()
if _, err := ts.LockSrvShardForAction("test", "test_keyspace", "10-20", "unused-fake-content", 5*time.Second, interrupted); err != topo.ErrInterrupted {
t.Errorf("LockSrvShardForAction(interrupted): %v", err)
}
// unlock now
if err := ts.UnlockSrvShardForAction("test", "test_keyspace", "10-20", lockPath, "fake-results"); err != nil {
t.Errorf("UnlockSrvShardForAction(): %v", err)
}
// test we can't unlock again
if err := ts.UnlockSrvShardForAction("test", "test_keyspace", "10-20", lockPath, "fake-results"); err == nil {
t.Error("UnlockSrvShardForAction(again) worked")
}
}
// LockSrvShard will lock the serving shard in the topology server.
// UnlockSrvShard should be called if this returns no error.
func (n *ActionNode) LockSrvShard(ts topo.Server, cell, keyspace, shard string, lockTimeout time.Duration, interrupted chan struct{}) (lockPath string, err error) {
log.Infof("Locking serving shard %v/%v/%v for action %v", cell, keyspace, shard, n.Action)
return ts.LockSrvShardForAction(cell, keyspace, shard, n.ToJson(), lockTimeout, interrupted)
}