public void DisableDirectWrites()
{
if (_scheduler != null)
{
_scheduler = null;
Log.Verbose("API will forward writes to leader");
}
}
async Task LeaderMethod(CancellationToken token, CloudPageBlob blob)
{
var processors = Environment.ProcessorCount;
int parallelism = processors / 2;
if (parallelism < 1)
{
parallelism = 1;
}
_log.Information("Node is a leader with {processors} processors. Setting parallelism to {parallelism}",
processors,
parallelism);
using (var source = new CancellationTokenSource())
using (var linked = CancellationTokenSource.CreateLinkedTokenSource(token, source.Token))
using (var scheduler = MessageWriteScheduler.Create(_account, parallelism, source)) {
try {
_log.Information("Message write scheduler created");
_api.EnableDirectWrites(scheduler);
// tell the world who is the leader
await _info.WriteToBlob(_account);
// sleep till cancelled
await Task.Delay(-1, linked.Token);
}
catch (OperationCanceledException) {
// expect this exception to be thrown in normal circumstances or check the cancellation token, because
// if the lease can't be renewed, the token will signal a cancellation request.
_log.Information("Shutting down the scheduler");
// shutdown the scheduler
_api.DisableDirectWrites();
var shutdown = scheduler.Shutdown();
if (shutdown.Wait(5000))
{
_log.Information("Scheduler is down");
}
else
{
_log.Error("Scheduler failed to shutdown in time");
}
}
finally {
_api.DisableDirectWrites();
_log.Information("This node is no longer a leader");
}
}
}
public void DisableDirectWrites() {
if (_scheduler != null) {
_scheduler = null;
Log.Verbose("API will forward writes to leader");
}
}
public void EnableDirectWrites(MessageWriteScheduler scheduler) {
_scheduler = scheduler;
Log.Verbose("API will handle writes on this node");
}
public void EnableDirectWrites(MessageWriteScheduler scheduler)
{
_scheduler = scheduler;
Log.Verbose("API will handle writes on this node");
}