async void _finish(XFlowState state)
{
if (!_persistOnComplete)
{
if (_state.Contains(state))
{
_state.Remove(state);
}
await _save();
return;
}
state.IsComplete = true;
Debug.WriteLine("Completed State Flow with {0}: {1}", state.PreviousStageSuccess, state);
if (state.PreviousStageSuccess)
{
state.State = XFlowStates.Success;
state.IsSuccessful = true;
state.Timestamp = DateTime.UtcNow;
await _save();
return;
}
state.State = XFlowStates.Fail;
state.IsSuccessful = false;
state.Timestamp = DateTime.UtcNow;
await _save();
}
bool _moveNextStage(XFlowState state)
{
if (state.StageId == null)
{
var firstStage = _stages.First();
state.StageId = firstStage.StageId;
return(true);
}
var stage = _getStage(state);
var index = _stages.IndexOf(stage);
var newIndex = index + 1;
if (newIndex >= _stages.Count)
{
//this is the last stage, so return false;
return(false);
}
var newStage = _stages[newIndex];
state.StageId = newStage.StageId;
state.FailureCount = 0;
return(true);
}
async Task _failResult(XFlowState state)
{
state.PreviousStageSuccess = false;
var stage = _getStage(state);
state.Text = stage.FailText;
if (stage.Retries > 0)
{
if (state.FailureCount <= stage.Retries)
{
//let's retry
state.FailureCount++;
state.State = XFlowStates.WaitingForRetry;
state.Timestamp = DateTime.UtcNow;
await _save();
_cancelProcessWait();
return;
}
}
await stage.Fail(state.ItemId);
Debug.WriteLine("Stage Failed [{0}] {1} - {2}",
state.ItemId,
state.PreviousStageResult != null ? state.PreviousStageResult.ExtraText : "No Extra Text",
state.PreviousStageResult != null ? state.PreviousStageResult.Exception : "No Exception");
Debug.WriteLine("Failure stage: {0}", stage.ProcessingText);
_finish(state);
}
public async Task <XFlowState> Start(Guid id)
{
if (!IsComplete)
{
throw new InvalidOperationException("Cannot start flows until Complete() is called");
}
var flowState = new XFlowState
{
Id = Guid.NewGuid(),
ItemId = id,
State = XFlowStates.WaitingForNextStage,
StageId = null,
Timestamp = DateTime.UtcNow,
ParentFlow = this
};
using (var l = await _stateLock.LockAsync())
{
var existing = _state.FirstOrDefault(_ => _.ItemId == id);
if (existing != null)
{
//if it's not failed or completed then clear it and start gain.
if (existing.State != XFlowStates.Fail && existing.State != XFlowStates.Success)
{
return(null);
}
_state.Remove(existing);
}
_state.Add(flowState);
}
await _save();
_cancelProcessWait();
return(flowState);
}
async Task _successResult(XFlowState state)
{
//state.Text = "";
state.PreviousStageSuccess = true;
if (state.PreviousStageResult != null && state.PreviousStageResult.CompleteNow)
{
//the result has asked for the workflow to complete early
//this could be because the rest isn't needed, e.g. an entity was detected
//locally so there is no need to get it form the server.
_finish(state);
return;
}
state.State = XFlowStates.WaitingForNextStage;
state.Timestamp = DateTime.UtcNow;
await _save();
_cancelProcessWait();
}
XStage _getStage(XFlowState state)
{
var stage = _stages.First(_ => _.StageId == state.StageId);
return(stage);
}
Task _runStage(XFlowState state)
{
if (state.State != XFlowStates.WaitingForNetwork && state.State != XFlowStates.WaitingForRetry &&
state.State != XFlowStates.WaitingToStart)
{
return(null);
}
if (_inProgressStates.Contains(state))
{
return(null);
}
var t = Task.Run(async() =>
{
var stage = _getStage(state);
if (stage.RequiresNetwork && !_networkStatus.QuickNetworkCheck())
{
state.State = XFlowStates.WaitingForNetwork;
await Task.Yield();
return;
}
state.Text = stage.ProcessingText;
state.State = XFlowStates.InProgress;
state.Timestamp = DateTime.UtcNow;
if (stage.IsDisconnectedProcess)
{
state.State = XFlowStates.DisconnectedProcessing;
await _save();
Debug.WriteLine("Stopping flow for disconnected state, will resume when asked. {0}", state);
return;
}
await _save();
XStageResult failResult = null;
try
{
if (_inProgressStates.Contains(state))
{
return;
}
_inProgressStates.Add(state);
var result = await stage.Function(state.ItemId);
if (result.Id != Guid.Empty)
{
state.ItemId = result.Id;
}
state.PreviousStageResult = result;
_inProgressStates.Remove(state);
if (!result.IsSuccess)
{
await _failResult(state);
}
else
{
await _successResult(state);
}
}
catch (Exception ex)
{
_inProgressStates.Remove(state);
failResult = new XStageResult(false, state.ItemId, null, exception: ex.ToString());
}
if (failResult != null)
{
state.PreviousStageResult = failResult;
var stateString = _entitySerialiser.Serialise(state);
Debug.WriteLine("Caught exception process: {0}", stateString);
await _failResult(state);
}
_cancelProcessWait();
});
return(t);
}
bool _moveNextStage(XFlowState state)
{
if (state.StageId == null)
{
var firstStage = _stages.First();
state.StageId = firstStage.StageId;
return true;
}
var stage = _getStage(state);
var index = _stages.IndexOf(stage);
var newIndex = index + 1;
if (newIndex >= _stages.Count)
{
//this is the last stage, so return false;
return false;
}
var newStage = _stages[newIndex];
state.StageId = newStage.StageId;
state.FailureCount = 0;
return true;
}
XStage _getStage(XFlowState state)
{
var stage = _stages.First(_ => _.StageId == state.StageId);
return stage;
}
async void _finish(XFlowState state)
{
if (!_persistOnComplete)
{
if (_state.Contains(state))
{
_state.Remove(state);
}
await _save();
return;
}
state.IsComplete = true;
Debug.WriteLine("Completed State Flow with {0}: {1}", state.PreviousStageSuccess, state);
if (state.PreviousStageSuccess)
{
state.State = XFlowStates.Success;
state.IsSuccessful = true;
state.Timestamp = DateTime.UtcNow;
await _save();
return;
}
state.State = XFlowStates.Fail;
state.IsSuccessful = false;
state.Timestamp = DateTime.UtcNow;
await _save();
}
async Task _successResult(XFlowState state)
{
//state.Text = "";
state.PreviousStageSuccess = true;
if (state.PreviousStageResult != null && state.PreviousStageResult.CompleteNow)
{
//the result has asked for the workflow to complete early
//this could be because the rest isn't needed, e.g. an entity was detected
//locally so there is no need to get it form the server.
_finish(state);
return;
}
state.State = XFlowStates.WaitingForNextStage;
state.Timestamp = DateTime.UtcNow;
await _save();
_cancelProcessWait();
}
async Task _failResult(XFlowState state)
{
state.PreviousStageSuccess = false;
var stage = _getStage(state);
state.Text = stage.FailText;
if (stage.Retries > 0)
{
if (state.FailureCount <= stage.Retries)
{
//let's retry
state.FailureCount++;
state.State = XFlowStates.WaitingForRetry;
state.Timestamp = DateTime.UtcNow;
await _save();
_cancelProcessWait();
return;
}
}
await stage.Fail(state.ItemId);
Debug.WriteLine("Stage Failed [{0}] {1} - {2}",
state.ItemId,
state.PreviousStageResult != null ? state.PreviousStageResult.ExtraText : "No Extra Text",
state.PreviousStageResult != null ? state.PreviousStageResult.Exception : "No Exception");
Debug.WriteLine("Failure stage: {0}", stage.ProcessingText);
_finish(state);
}
Task _runStage(XFlowState state)
{
if (state.State != XFlowStates.WaitingForNetwork && state.State != XFlowStates.WaitingForRetry &&
state.State != XFlowStates.WaitingToStart)
{
return null;
}
if (_inProgressStates.Contains(state))
{
return null;
}
var t = Task.Run(async () =>
{
var stage = _getStage(state);
if (stage.RequiresNetwork && !_networkStatus.QuickNetworkCheck())
{
state.State = XFlowStates.WaitingForNetwork;
await Task.Yield();
return;
}
state.Text = stage.ProcessingText;
state.State = XFlowStates.InProgress;
state.Timestamp = DateTime.UtcNow;
if (stage.IsDisconnectedProcess)
{
state.State = XFlowStates.DisconnectedProcessing;
await _save();
Debug.WriteLine("Stopping flow for disconnected state, will resume when asked. {0}", state);
return;
}
await _save();
XStageResult failResult = null;
try
{
if (_inProgressStates.Contains(state))
{
return;
}
_inProgressStates.Add(state);
var result = await stage.Function(state.ItemId);
if (result.Id != Guid.Empty)
{
state.ItemId = result.Id;
}
state.PreviousStageResult = result;
_inProgressStates.Remove(state);
if (!result.IsSuccess)
{
await _failResult(state);
}
else
{
await _successResult(state);
}
}
catch (Exception ex)
{
_inProgressStates.Remove(state);
failResult = new XStageResult(false, state.ItemId, null, exception: ex.ToString());
}
if (failResult != null)
{
state.PreviousStageResult = failResult;
var stateString = _entitySerialiser.Serialise(state);
Debug.WriteLine("Caught exception process: {0}", stateString);
await _failResult(state);
}
_cancelProcessWait();
});
return t;
}
public async Task<XFlowState> Start(Guid id)
{
if (!IsComplete)
{
throw new InvalidOperationException("Cannot start flows until Complete() is called");
}
var flowState = new XFlowState
{
Id = Guid.NewGuid(),
ItemId = id,
State = XFlowStates.WaitingForNextStage,
StageId = null,
Timestamp = DateTime.UtcNow,
ParentFlow = this
};
using (var l = await _stateLock.LockAsync())
{
var existing = _state.FirstOrDefault(_ => _.ItemId == id);
if (existing != null)
{
//if it's not failed or completed then clear it and start gain.
if (existing.State != XFlowStates.Fail && existing.State != XFlowStates.Success)
{
return null;
}
_state.Remove(existing);
}
_state.Add(flowState);
}
await _save();
_cancelProcessWait();
return flowState;
}
