private async Task RunTask(IFdbDatabase db, FdbWorkerMessage msg, Func <FdbWorkerMessage, CancellationToken, Task> handler, CancellationToken ct)
{
var sw = Stopwatch.StartNew();
try
{
Interlocked.Increment(ref m_workerTasksReceived);
//TODO: custom TaskScheduler for task execution ?
await handler(msg, ct).ConfigureAwait(false);
Interlocked.Increment(ref m_workerTasksCompleted);
}
finally
{
sw.Stop();
Interlocked.Add(ref m_workerBusyTime, sw.ElapsedTicks);
}
}
private async Task RunTask(IFdbDatabase db, FdbWorkerMessage msg, Func<FdbWorkerMessage, CancellationToken, Task> handler, CancellationToken ct)
{
var sw = Stopwatch.StartNew();
try
{
Interlocked.Increment(ref m_workerTasksReceived);
//TODO: custom TaskScheduler for task execution ?
await handler(msg, ct).ConfigureAwait(false);
Interlocked.Increment(ref m_workerTasksCompleted);
}
finally
{
sw.Stop();
Interlocked.Add(ref m_workerBusyTime, sw.ElapsedTicks);
}
}
/// <summary>Run the worker loop</summary>
public async Task RunWorkerAsync(IFdbDatabase db, Func<FdbWorkerMessage, CancellationToken, Task> handler, CancellationToken ct)
{
int num = Interlocked.Increment(ref counter);
Slice workerId = Slice.Nil;
Slice previousTaskId = Slice.Nil;
FdbWatch watch = default(FdbWatch);
FdbWorkerMessage msg = null;
Interlocked.Increment(ref m_workers);
try
{
while (true)
{
//TODO: how do we clear the previousTaskId from the db in case of cancellation ?
ct.ThrowIfCancellationRequested();
Slice myId = Slice.Nil;
await db.ReadWriteAsync(
async (tr) =>
{
tr.Annotate("I'm worker #{0} with id {1}", num, workerId.ToAsciiOrHexaString());
myId = workerId;
watch = default(FdbWatch);
msg = new FdbWorkerMessage();
if (previousTaskId != null)
{ // we need to clean up the previous task
ClearTask(tr, previousTaskId);
}
else if (myId.IsPresent)
{ // look for an already assigned task
tr.Annotate("Look for already assigned task");
msg.Id = await tr.GetAsync(this.BusyRing.Pack(myId)).ConfigureAwait(false);
}
if (!msg.Id.IsPresent)
{ // We aren't already assigned a task, so get an item from a random queue
tr.Annotate("Look for next queued item");
// Find the next task on the queue
var item = await tr.GetRange(this.UnassignedTaskRing.ToRange()).FirstOrDefaultAsync().ConfigureAwait(false);
if (item.Key != null)
{ // pop the Task from the queue
msg.Id = item.Value;
tr.Clear(item.Key);
}
if (msg.Id.IsPresent)
{ // mark this worker as busy
// note: we need a random id so generate one if it is the first time...
if (!myId.IsPresent) myId = GetRandomId();
tr.Annotate("Found {0}, switch to busy with id {1}", msg.Id.ToAsciiOrHexaString(), myId.ToAsciiOrHexaString());
tr.Set(this.BusyRing.Pack(myId), msg.Id);
this.Counters.Increment(tr, COUNTER_BUSY);
}
else if (myId.IsPresent)
{ // remove ourselves from the busy ring
tr.Annotate("Found nothing, switch to idle with id {0}", myId.ToAsciiOrHexaString());
//tr.Clear(this.BusyRing.Pack(myId));
}
}
if (msg.Id.IsPresent)
{ // get the task body
tr.Annotate("Fetching body for task {0}", msg.Id.ToAsciiOrHexaString());
var prefix = this.TaskStore.Partition(msg.Id);
//TODO: replace this with a get_range ?
var data = await tr.GetValuesAsync(new [] {
prefix.Key,
prefix.Pack(TASK_META_SCHEDULED)
}).ConfigureAwait(false);
msg.Body = data[0];
msg.Scheduled = new DateTime(data[1].ToInt64(), DateTimeKind.Utc);
msg.Received = DateTime.UtcNow;
}
else
{ // There are no unassigned task, so enter the idle_worker_ring and wait for a task to be asssigned to us
// remove us from the busy ring
if (myId.IsPresent)
{
tr.Clear(this.BusyRing.Pack(myId));
this.Counters.Decrement(tr, COUNTER_BUSY);
}
// choose a new random position on the idle ring
myId = GetRandomId();
// the idle key will also be used as the watch key to wake us up
var watchKey = this.IdleRing.Pack(myId);
tr.Annotate("Will start watching on key {0} with id {1}", watchKey.ToAsciiOrHexaString(), myId.ToAsciiOrHexaString());
tr.Set(watchKey, Slice.Empty);
this.Counters.Increment(tr, COUNTER_IDLE);
watch = tr.Watch(watchKey, ct);
}
},
onDone: (tr) =>
{ // we have successfully acquired some work, or got a watch
previousTaskId = Slice.Nil;
workerId = myId;
},
cancellationToken: ct
).ConfigureAwait(false);
if (msg.Id.IsNullOrEmpty)
{ // wait for someone to wake us up...
Interlocked.Increment(ref m_idleWorkers);
try
{
await watch.Task;
//Console.WriteLine("Worker #" + num + " woken up!");
}
finally
{
Interlocked.Decrement(ref m_idleWorkers);
}
}
else
{
//Console.WriteLine("Got task " + taskId);
previousTaskId = msg.Id;
if (msg.Body.IsNull)
{ // the task has been dropped?
// TODO: loggin?
Console.WriteLine("[####] Task[" + msg.Id.ToAsciiOrHexaString() + "] has vanished?");
}
else
{
try
{
await RunTask(db, msg, handler, ct);
}
catch (Exception e)
{
//TODO: logging?
Console.Error.WriteLine("Task[" + msg.Id.ToAsciiOrHexaString() + "] failed: " + e.ToString());
}
}
}
}
}
finally
{
//TODO: we should ensure that the last processed task is properly removed from the db before leaving !
Interlocked.Decrement(ref m_workers);
}
}
/// <summary>Run the worker loop</summary>
public async Task RunWorkerAsync(IFdbDatabase db, Func <FdbWorkerMessage, CancellationToken, Task> handler, CancellationToken ct)
{
int num = Interlocked.Increment(ref s_counter);
Slice workerId = Slice.Nil;
Slice previousTaskId = Slice.Nil;
FdbWatch watch = null;
FdbWorkerMessage msg = null;
Interlocked.Increment(ref m_workers);
try
{
while (true)
{
//TODO: how do we clear the previousTaskId from the db in case of cancellation ?
ct.ThrowIfCancellationRequested();
Slice myId = Slice.Nil;
await db.ReadWriteAsync(
async (tr) =>
{
tr.Annotate("I'm worker #{0} with id {1:P}", num, workerId);
myId = workerId;
watch = null;
msg = new FdbWorkerMessage();
if (previousTaskId != null)
{ // we need to clean up the previous task
ClearTask(tr, previousTaskId);
}
else if (myId.IsPresent)
{ // look for an already assigned task
tr.Annotate("Look for already assigned task");
msg.Id = await tr.GetAsync(this.BusyRing.Keys.Encode(myId)).ConfigureAwait(false);
}
if (!msg.Id.IsPresent)
{ // We aren't already assigned a task, so get an item from a random queue
tr.Annotate("Look for next queued item");
// Find the next task on the queue
var item = await tr.GetRange(this.UnassignedTaskRing.Keys.ToRange()).FirstOrDefaultAsync().ConfigureAwait(false);
if (item.Key != null)
{ // pop the Task from the queue
msg.Id = item.Value;
tr.Clear(item.Key);
}
if (msg.Id.IsPresent)
{ // mark this worker as busy
// note: we need a random id so generate one if it is the first time...
if (!myId.IsPresent)
{
myId = GetRandomId();
}
tr.Annotate("Found {0:P}, switch to busy with id {1:P}", msg.Id, myId);
tr.Set(this.BusyRing.Keys.Encode(myId), msg.Id);
this.Counters.Increment(tr, COUNTER_BUSY);
}
else if (myId.IsPresent)
{ // remove ourselves from the busy ring
tr.Annotate("Found nothing, switch to idle with id {0:P}", myId);
//tr.Clear(this.BusyRing.Pack(myId));
}
}
if (msg.Id.IsPresent)
{ // get the task body
tr.Annotate("Fetching body for task {0:P}", msg.Id);
var prefix = this.TaskStore.Partition.ByKey(msg.Id);
//TODO: replace this with a get_range ?
var data = await tr.GetValuesAsync(new [] {
prefix.GetPrefix(),
prefix.Keys.Encode(TASK_META_SCHEDULED)
}).ConfigureAwait(false);
msg.Body = data[0];
msg.Scheduled = new DateTime(data[1].ToInt64(), DateTimeKind.Utc);
msg.Received = DateTime.UtcNow;
}
else
{ // There are no unassigned task, so enter the idle_worker_ring and wait for a task to be asssigned to us
// remove us from the busy ring
if (myId.IsPresent)
{
tr.Clear(this.BusyRing.Keys.Encode(myId));
this.Counters.Decrement(tr, COUNTER_BUSY);
}
// choose a new random position on the idle ring
myId = GetRandomId();
// the idle key will also be used as the watch key to wake us up
var watchKey = this.IdleRing.Keys.Encode(myId);
tr.Annotate("Will start watching on key {0:P} with id {1:P}", watchKey, myId);
tr.Set(watchKey, Slice.Empty);
this.Counters.Increment(tr, COUNTER_IDLE);
watch = tr.Watch(watchKey, ct);
}
},
success : (tr) =>
{ // we have successfully acquired some work, or got a watch
previousTaskId = Slice.Nil;
workerId = myId;
},
ct : ct
).ConfigureAwait(false);
if (msg.Id.IsNullOrEmpty)
{ // wait for someone to wake us up...
Interlocked.Increment(ref m_idleWorkers);
try
{
await watch.Task;
//Console.WriteLine("Worker #" + num + " woken up!");
}
finally
{
Interlocked.Decrement(ref m_idleWorkers);
}
}
else
{
//Console.WriteLine("Got task " + taskId);
previousTaskId = msg.Id;
if (msg.Body.IsNull)
{ // the task has been dropped?
// TODO: loggin?
#if DEBUG
Console.WriteLine($"[####] Task[{msg.Id:P}] has vanished?");
#endif
}
else
{
try
{
await RunTask(db, msg, handler, ct);
}
catch (Exception e)
{
//TODO: logging?
#if DEBUG
Console.Error.WriteLine($"Task[{msg.Id:P}] failed: {e}");
#endif
}
}
}
}
}
finally
{
//TODO: we should ensure that the last processed task is properly removed from the db before leaving !
Interlocked.Decrement(ref m_workers);
}
}