public void Start()
{
// use a persistent site map repository for the duration of worker lifetime
TraceLog.TraceDetail("Initializing Site Map Repository");
Stopwatch stopwatch = new Stopwatch();
stopwatch.Start();
var SiteMapRepository = Storage.NewSiteMapRepository;
var versionString = SiteMapRepository.Initialize(Me);
stopwatch.Stop();
TraceLog.TraceDetail(string.Format(
"Initialized Site Map Repository version {0}: {1:F2} secs",
versionString,
stopwatch.ElapsedMilliseconds / 1000));
string lastRecordId = null;
bool isPoisonMessage = false;
// run an infinite loop doing the following:
// grab records from the collector database
// process records into session records in the user database
// mark the processed records
// sleep for the timeout period
while (true)
{
// reinitialize the mapping database if the version changed
if (SiteMapRepository.VersionChanged())
{
stopwatch.Start();
versionString = SiteMapRepository.Initialize(Me);
stopwatch.Stop();
TraceLog.TraceInfo(string.Format(
"Re-Initialized Site Map Repository version {0}: {1:F2} secs",
versionString,
stopwatch.ElapsedMilliseconds / 1000));
}
var UserContext = Storage.NewUserDataContext;
var CollectorContext = Storage.NewCollectorContext;
try
{
DateTime now = DateTime.UtcNow;
var record = CollectorContext.GetRecordToProcess(Me);
if (record != null && record.RecordList.Count() > 0)
{
try
{
// poison message processing
if (record.Id == lastRecordId)
{
// was this a suspected poison message (meaning, this is the third time we've seen it?)
if (isPoisonMessage)
{
TraceLog.TraceInfo(string.Format("Detected poison message {0} for user {1}", record.Id, record.UserId));
CollectorContext.Delete(record);
isPoisonMessage = false;
lastRecordId = null;
continue;
}
else
{
isPoisonMessage = true;
}
}
else
{
// new record ID
lastRecordId = record.Id;
isPoisonMessage = false;
}
// get all the in-progress sessions belonging to the userid
var userId = record.UserId;
var sessions = UserContext.WebSessions.Where(ws => ws.Device.UserId == userId && ws.Device.DeviceId == record.DeviceId && ws.InProgress == true).OrderBy(ws => ws.Start);
// process the records against the existing sessions
var workingSessions = RecordProcessor.ProcessRecords(
SiteMapRepository,
sessions.ToList <WebSession>(),
record);
// process the resultant sessions
foreach (var session in workingSessions)
{
if (session.WebSessionId == 0)
{ // new session
// find out whether the device already exists
var device = UserContext.Devices.FirstOrDefault(d => d.DeviceId == session.DeviceId);
if (device == null)
{
try
{
// create a new device and save it immediately
device = UserDataContext.CreateDeviceFromSession(session);
UserContext.Devices.Add(device);
UserContext.SaveChanges();
TraceLog.TraceInfo(string.Format("Added device {0} to user {1}; Device dump: {2}", device.Name, userId, JsonSerializer.Serialize(device)));
}
catch (DbEntityValidationException ex)
{
var str = new StringBuilder("Failed to create new device. Validation errors:\n");
foreach (var errors in ex.EntityValidationErrors)
{
foreach (var result in errors.ValidationErrors)
{
str.AppendLine(string.Format("\tProperty: {0}; Error: {1}", result.PropertyName, result.ErrorMessage));
}
}
TraceLog.TraceException(str.ToString(), ex);
TraceLog.TraceError(string.Format("Session dump: {0}; Device dump: {1}", JsonSerializer.Serialize(session), JsonSerializer.Serialize(device)));
// fail fast
throw;
}
}
else
{
// ensure device belongs to current user
if (device.UserId != userId)
{
TraceLog.TraceError(string.Format(
"Possible security issue: User {0} is trying to claim Device {0} that already belongs to User {2}",
userId,
session.DeviceId,
device.UserId));
// TODO: do something smarter than ignoring the record
continue;
}
}
// create a new session with the correct device
session.Device = device;
UserContext.WebSessions.Add(session);
}
else
{
var sessionToModify = sessions.Single(s => s.WebSessionId == session.WebSessionId);
sessionToModify.Duration = session.Duration;
sessionToModify.InProgress = session.InProgress;
}
}
// save all the sessions
UserContext.SaveChanges();
// remove the processed record
CollectorContext.Delete(record);
TraceLog.TraceInfo(string.Format("Processed {0} sessions for user {1}", workingSessions.Count(), userId));
}
catch (Exception ex)
{
TraceLog.TraceException("Could not save session changes", ex);
// unlock the record so that it can get processed by the next iteration
record.State = RecordState.New;
CollectorContext.Update(record);
// poison message detection and processing is done at the start of the while block
}
// keep reading records until they are all processed
continue;
}
}
catch (Exception ex)
{
TraceLog.TraceException("Collector processing failed", ex);
}
// sleep for the timeout period
Thread.Sleep(Timeout);
}
}