public async Task <MethodExecutionState> ReadStateAsync(ServiceId serviceId, PersistedMethodId methodId, CancellationToken ct)
{
var fileName = GetStateFileName(serviceId, methodId);
var filePath = Path.Combine(_stateDirectory, fileName);
string etag;
byte[] data;
try
{
using (var fileStream = new FileStream(
filePath, FileMode.Open, FileAccess.Read, FileShare.Read,
FileBufferSize, FileOptions.Asynchronous))
{
etag = TryGetETag(filePath);
data = new byte[fileStream.Length];
await fileStream.ReadAsync(data, 0, data.Length);
}
}
catch (IOException)
{
throw new StateNotFoundException(serviceId, methodId);
}
// TODO: select serializer
var executionState = _serializer.Deserialize <MethodExecutionState>(data);
return(executionState);
}
public Task <MethodExecutionState> ReadStateAsync(
ServiceId serviceId,
PersistedMethodId methodId,
CancellationToken ct)
{
MethodExecutionState executionState;
string serializedFlowContext;
string serializedContinuation;
string continuationStateFormat;
byte[] continuationStateData;
lock (_entryMap)
{
if (!_entryMap.TryGetValue(methodId.IntentId, out var entry))
{
throw new StateNotFoundException(serviceId, methodId);
}
executionState = new MethodExecutionState
{
Service = serviceId,
Method = methodId,
Caller = entry.TryGetValue("Caller", out var callerObj) ? callerObj as CallerDescriptor : null,
MethodState = new SerializedValueContainer((string)entry["State"], _serializer)
};
executionState.Method.ETag = entry.ETag;
serializedFlowContext = entry.TryGetValue("FlowContext", out var flowContextObj) ? flowContextObj as string : null;
serializedContinuation = entry.TryGetValue("Continuation", out var continuationObj) ? continuationObj as string : null;
continuationStateFormat = entry.TryGetValue("Continuation:Format", out var continuationStateFormatObj) ? continuationStateFormatObj as string : null;
continuationStateData = entry.TryGetValue("Continuation:State", out var continuationStateDataObj) ? continuationStateDataObj as byte[] : null;
}
if (!string.IsNullOrEmpty(serializedFlowContext))
{
executionState.FlowContext = _serializer.Deserialize <Dictionary <string, string> >(serializedFlowContext);
}
if (!string.IsNullOrEmpty(serializedContinuation))
{
executionState.Continuation = _serializer.Deserialize <ContinuationDescriptor>(serializedContinuation);
}
if (continuationStateData?.Length > 0)
{
executionState.ContinuationState = new SerializedMethodContinuationState
{
Format = continuationStateFormat,
State = continuationStateData
};
}
return(Task.FromResult(executionState));
}
public async Task <string> WriteStateAsync(ServiceId serviceId, PersistedMethodId methodId, MethodExecutionState state)
{
var tableName = GetTableQualifiedName(serviceId, methodId);
var key = new StorageRecord
{
service = serviceId.Name,
method = methodId.Name,
intent_id = methodId.IntentId
};
var record = new StorageRecord
{
etag = DateTimeOffset.UtcNow.Ticks,
status = (int)Statuses.Paused,
updated_at = DateTimeOffset.Now,
caller_service = state.Caller?.Service?.Name,
caller_proxy = state.Caller?.Service?.Proxy,
caller_method = state.Caller?.Method?.Name,
caller_event = state.Caller?.Event?.Name,
caller_intent_id = state.Caller?.IntentId,
format = _serializer.Format,
execution_state = _serializer.SerializeToBytes(state),
};
var query = new StringBuilder("UPDATE ").Append(tableName);
query.Append(" SET ");
WriteValues(query, record, delimiter: ", ");
query.Append(" WHERE ");
WriteValues(query, key, delimiter: " AND ");
if (!string.IsNullOrEmpty(methodId.ETag))
{
query.Append(" IF etag = ").AppendCqlText(methodId.ETag);
}
var result = await ExecuteQueryAsync(serviceId, methodId, query.ToString());
if (result != null)
{
var row = result.FirstOrDefault();
if (row != null && !row.GetValue <bool>("[applied]"))
{
var actualETag = row.GetValueOrDefault <long>("etag");
throw new ETagMismatchException(methodId.ETag, actualETag.ToString());
}
}
return(record.etag.ToString());
}
public void OnRoutineStart(
IServiceReference serviceRef,
IMethodReference methodRef,
PersistedMethodId methodId,
object serviceInstance,
IAsyncStateMachine routineStateMachine,
CallerDescriptor caller)
{
Context.ServiceRef = serviceRef;
Context.MethodRef = methodRef;
Context.MethodId = methodId;
Context.ServiceInstance = serviceInstance;
Context.RoutineStateMachine = routineStateMachine;
Context.Caller = caller;
_intrinsicFlowController.OnRoutineStart(this);
}
public async Task <MethodExecutionState> ReadStateAsync(ServiceId serviceId, PersistedMethodId methodId, CancellationToken ct)
{
var tableName = GetTableQualifiedName(serviceId, methodId);
var key = new StorageRecord
{
service = serviceId.Name,
method = methodId.Name,
intent_id = methodId.IntentId
};
var query = new StringBuilder("SELECT * FROM ")
.Append(tableName).Append(" WHERE ");
WriteValues(query, key, delimiter: " AND ");
var result = await ExecuteQueryAsync(serviceId, methodId, query.ToString());
var row = result.FirstOrDefault();
if (row == null)
{
throw new StateNotFoundException(serviceId, methodId);
}
var record = ReadValues(row);
if (record.status.HasValue && record.status.Value != (int)Statuses.Paused)
{
throw new InvalidOperationException("Method is not paused");
}
if (!(record.execution_state?.Length > 0))
{
throw new InvalidOperationException("Empty state data");
}
var serializer = !string.IsNullOrEmpty(record.format)
? _serializerProvider.GetSerializer(record.format)
: _serializer;
return(serializer.Deserialize <MethodExecutionState>(record.execution_state));
}
public Task <string> WriteStateAsync(
ServiceId serviceId,
PersistedMethodId methodId,
MethodExecutionState state)
{
var serializedState = _serializer.SerializeToString(state.MethodState);
var serializedContinuation = state.Continuation != null?_serializer.SerializeToString(state.Continuation) : null;
var serializedFlowContext = state.FlowContext?.Count > 0 ? _serializer.SerializeToString(state.FlowContext) : null;
var expectedETag = methodId.ETag;
var intentId = methodId.IntentId;
lock (_entryMap)
{
if (!_entryMap.TryGetValue(intentId, out var entry))
{
entry = new StorageEntry();
_entryMap.Add(intentId, entry);
}
else if (!string.IsNullOrEmpty(expectedETag) && entry.ETag != expectedETag)
{
throw new ETagMismatchException(expectedETag, entry.ETag);
}
entry.ETag = DateTimeOffset.UtcNow.Ticks.ToString();
entry["ServiceId"] = state.Service.Clone();
entry["MethodId"] = state.Method.Clone();
entry["Caller"] = state.Caller?.Clone();
entry["State"] = serializedState;
entry["Continuation"] = serializedContinuation;
entry["FlowContext"] = serializedFlowContext;
if (state.ContinuationState != null)
{
entry["Continuation:Format"] = state.ContinuationState.Format;
entry["Continuation:State"] = state.ContinuationState.State;
}
return(Task.FromResult(entry.ETag));
}
}
public async Task <string> WriteStateAsync(
ServiceId serviceId,
PersistedMethodId methodId,
MethodExecutionState state)
{
var fileName = GetStateFileName(serviceId, methodId);
var filePath = Path.Combine(_stateDirectory, fileName);
var data = _serializer.SerializeToBytes(state);
EnsureDirectoryExists(_stateDirectory);
@TryWrite:
var tryCount = 10;
try
{
using (var fileStream = new FileStream(
filePath, FileMode.Create, FileAccess.ReadWrite, FileShare.Read,
FileBufferSize, FileOptions.Asynchronous | FileOptions.WriteThrough))
{
var etag = TryGetETag(filePath);
if (fileStream.Length > 0 && !string.IsNullOrEmpty(methodId.ETag) && methodId.ETag != etag)
{
throw new ETagMismatchException(methodId.ETag, etag);
}
await fileStream.WriteAsync(data, 0, data.Length);
fileStream.SetLength(fileStream.Position);
return(etag);
}
}
catch (IOException) when(tryCount > 0)
{
await Task.Yield();
tryCount--;
goto @TryWrite;
}
}
public StateNotFoundException(ServiceId service, PersistedMethodId method) : this()
{
Service = service;
Method = method;
}
private string GetStateFileName(ServiceId serviceId, PersistedMethodId methodId)
{
// TODO: suffix for the format? e.g. '.json', '.gz'
return($"{methodId.IntentId}.{serviceId.Name}.{methodId.Name}.state");
}