/// <summary>
/// Registers the specified shellContext as dependent such that it is also released when the current shell context is released.
/// </summary>
public void AddDependentShell(ShellContext shellContext)
{
// If the dependent is released, nothing to do.
if (shellContext.Released)
{
return;
}
// If the dependency is already released.
if (_released)
{
// The dependent is released immediately.
shellContext.Release();
return;
}
lock (_synLock)
{
if (_dependents == null)
{
_dependents = new List <WeakReference <ShellContext> >();
}
// Remove any previous instance that represent the same tenant in case it has been released (restarted).
_dependents.RemoveAll(x => !x.TryGetTarget(out var shell) || shell.Settings.Name == shellContext.Settings.Name);
_dependents.Add(new WeakReference <ShellContext>(shellContext));
}
}
/// <summary>
/// Tries to acquire a lock for shell activation, a local lock if it is initializing, otherwise a distributed lock.
/// </summary>
public static Task <(ILocker locker, bool locked)> TryAcquireShellActivateLockAsync(this ShellContext shellContext)
{
// If the shell is initializing, force the usage of a local lock.
var lockService = shellContext.Settings.State == TenantState.Initializing
? (ILock)shellContext.ServiceProvider.GetRequiredService <ILocalLock>()
: shellContext.ServiceProvider.GetRequiredService <IDistributedLock>();
TimeSpan timeout, expiration;
if (lockService is ILocalLock)
{
// If it is a local lock, don't use any timeout and expiration.
timeout = expiration = TimeSpan.MaxValue;
}
else
{
// If it is a distributed lock, use the configured timeout and expiration.
var options = shellContext.ServiceProvider.GetRequiredService <IOptions <ShellContextOptions> >();
timeout = TimeSpan.FromMilliseconds(options.Value.ShellActivateLockTimeout);
expiration = TimeSpan.FromMilliseconds(options.Value.ShellActivateLockExpiration);
}
return(lockService.TryAcquireLockAsync("SHELL_ACTIVATE_LOCK", timeout, expiration));
}
