internal static bool TryReadRoutineData(string directory, string routineId, out RoutineDataEnvelope dataEnvelope, out string eTag)
{
var fileName = routineId + ".json";
var filePath = Path.Combine(directory, fileName);
if (File.Exists(filePath))
{
for (var i = 0; i < 10; i++)
{
try
{
var json = File.ReadAllText(filePath);
eTag = new DateTimeOffset(File.GetLastWriteTimeUtc(filePath)).ToString("o");
dataEnvelope = JsonConvert.DeserializeObject <RoutineDataEnvelope>(
json, CloudEventsSerialization.JsonSerializerSettings);
return(true);
}
catch (IOException) // File is being used by another process.
{
Thread.Sleep(1);
continue;
}
}
}
eTag = null;
dataEnvelope = null;
return(false);
}
private void UpsertRoutineData(string routineId, string expectedETag, Action <RoutineDataEnvelope> updateAction)
{
var fileName = routineId + ".json";
var filePath = Path.Combine(_fabric.RoutinesDirectory, fileName);
var fileStream = new FileStream(filePath, FileMode.OpenOrCreate, FileAccess.ReadWrite, FileShare.Read, 4096);
#warning need more precise error handling here - what if file is locked?
using (fileStream)
{
RoutineDataEnvelope routineDataEnvelope;
if (fileStream.Length > 0)
{
var routineETag = new DateTimeOffset(File.GetLastWriteTimeUtc(filePath)).ToString("o");
if (!string.IsNullOrEmpty(expectedETag) && expectedETag != routineETag)
{
throw new ConcurrentRoutineExecutionException(
new ETagMismatchException());
}
using (var textReader = new StreamReader(fileStream, Encoding.UTF8, true, 512, leaveOpen: true))
routineDataEnvelope = (RoutineDataEnvelope)_jsonSerializer.Deserialize(textReader, typeof(RoutineDataEnvelope));
fileStream.Position = 0;
}
else
{
routineDataEnvelope = new RoutineDataEnvelope();
}
updateAction(routineDataEnvelope);
using (var textWriter = new StreamWriter(fileStream, Encoding.UTF8, 512, leaveOpen: true))
_jsonSerializer.Serialize(textWriter, routineDataEnvelope);
fileStream.SetLength(fileStream.Position);
}
}