private static void PessimisticLockingExample2(IBucket bucket)
{
// tag::PessimisticLockingExample2[]
bucket.Upsert("mymagic", new { magicLevel = 1, name = "Fire Magic" });
// alternatively, if A never gets around to releasing the lock
// then the lock will automatically be released after a certain time
var magicAResult = bucket.GetAndLock <dynamic>("mymagic", TimeSpan.FromMilliseconds(5000));
if (magicAResult.Success)
{
Console.WriteLine("Got a lock on 'mymagic'");
}
// try to get a new lock every second
for (var i = 0; i < 10; i++)
{
var magicBResult = bucket.GetAndLock <dynamic>("mymagic", TimeSpan.FromMilliseconds(5000));
if (magicBResult.Success)
{
Console.WriteLine("Got a new lock on 'mymagic'!");
bucket.Unlock("mymagic", magicBResult.Cas); // unlock it right away
break;
}
else
{
Console.WriteLine("'mymagic' document is still locked.");
}
Thread.Sleep(1000);
}
// end::PessimisticLockingExample2[]
}
private static void PessimisticLockingExample1(IBucket bucket)
{
// tag::PessimisticLockingExample1[]
// create initial document
bucket.Upsert("myshield", new { defenseLevel = 1, name = "Mirror Shield" });
// document is retrieved and locked by A
var shieldAResult = bucket.GetAndLock <dynamic>("myshield", TimeSpan.FromMilliseconds(30000));
var shieldA = shieldAResult.Value;
// B attempts to get and lock it as well
var shieldBResult = bucket.GetAndLock <dynamic>("myshield", TimeSpan.FromMilliseconds(30000));
if (!shieldBResult.Success)
{
Console.WriteLine("B couldn't establish a lock, trying a plain Get");
shieldBResult = bucket.Get <dynamic>("myshield");
}
// B tries to make a change, despite not having a lock
Console.WriteLine("'B' is updating the document");
var shieldB = shieldBResult.Value;
shieldB.defenseLevel = 3;
IOperationResult bResult = bucket.Replace("myshield", shieldB);
if (!bResult.Success)
{
Console.WriteLine($"B was unable to make a change: {bResult.Message}");
Console.WriteLine();
}
// A can make the change, but MUST use the CAS value
shieldA.defenseLevel = 2;
IOperationResult aResult = bucket.Replace("myshield", shieldA);
if (!aResult.Success)
{
Console.WriteLine($"A tried to make a change, but forgot to use a CAS value: {aResult.Message}");
Console.WriteLine();
Console.WriteLine("Trying again with CAS this time");
aResult = bucket.Replace("myshield", shieldA, shieldAResult.Cas);
if (aResult.Success)
{
Console.WriteLine("Success!");
}
}
// now, the document is unlocked
// so B can try again
bResult = bucket.Replace("myshield", shieldB);
if (bResult.Success)
{
Console.WriteLine($"B was able to make a change.");
}
// end::PessimisticLockingExample1[]
}
public void GetWithLock_WhenKeyIsLocked_ResponseStatusIsTemporaryFailure_And_MessageIsLOCK_ERROR()
{
_bucket.Upsert("roikatz", "bbbb");
var res1 = _bucket.GetAndLock <string>("roikatz", 30);
Assert.IsTrue(res1.Success);
var res2 = _bucket.GetAndLock <string>("roikatz", 30);
Assert.IsFalse(res2.Success);
Assert.AreEqual(ResponseStatus.TemporaryFailure, res2.Status);
}
