public void PublishCollectorPullEvent(CollectorPullEvent newEvent)
{
this.PublishEvent(newEvent,
this.config.collectorTopic,
this.config.pullEventFilter);
}
private async void timerEvent(Object source, ElapsedEventArgs arg)
{
// prevent calling this method again until the current execution is done
// in case timer.Interval is shorter than the time required to pull data
// from all the sensors
timer.Stop();
ConfigFields config = ServiceConfiguration.Instance;
List <SensorRegistryRecord> availableSensors =
await mediator.Send(new GetAllSensorsRequest());
int triedToPullCount = 0;
Console.WriteLine($"Available sensors count: {availableSensors.Count} ... ");
foreach (var singleSensor in availableSensors)
{
long alreadyReadCount = 0;
if (!lastReadIndexes.TryGetValue(
singleSensor.Name,
out alreadyReadCount))
{
// get the count of already read records from this sensor
// db access
alreadyReadCount = await mediator
.Send(new GetRecordsCountRequest(singleSensor.Name));
if (alreadyReadCount == -1)
{
Console.WriteLine("Failed to get read count for: "
+ $"{singleSensor.Name}");
// something went wrong
// most possibly failed to connect with the db
continue; // read from the next senor
}
lastReadIndexes.Add(singleSensor.Name, alreadyReadCount);
}
if (alreadyReadCount >= singleSensor.AvailableRecords)
{
long diff = alreadyReadCount - singleSensor.AvailableRecords;
Console.WriteLine($"{singleSensor.Name} -> no new records "
+ $"waiting for: {diff} reads ... ");
continue; // read from the next sensor
}
string sensorAddr = $"http://{singleSensor.Address}:{singleSensor.Port}";
string api_url = $"{sensorAddr}/{config.dataRangeUrl}?"
+ $"sensorName={singleSensor.Name}&"
+ $"index={alreadyReadCount}";
Uri sensorUri = new Uri(api_url);
Console.Write($"{singleSensor.Name}@{sensorAddr} "
+ $" | from: {alreadyReadCount} -> ");
HttpResponseMessage response = null;
try
{
triedToPullCount++;
response = await this.httpClient.GetAsync(sensorUri);
}
catch (AggregateException e)
{
// most possibly this exception happened because data pulling
// is started with old list of sensors
// sensors are removed from registry (shutdown events are received)
// after 'current sensors list is returned'
if (e.InnerException is HttpRequestException)
{
string message =
((HttpRequestException)e.InnerException).Message;
Console.WriteLine(
$"\nHttp req. exception, message: {message} ... "
+ $"sensor may be down.\n"
+ $"Sensor addr. : {sensorUri.ToString()}\n");
var newEvent = new CollectorPullEvent(
config.serviceId,
sensorUri.ToString(),
false,
0,
e.Message);
// handler for this request is not async
// but i guess it is a good idea to await it anyway
await mediator.Send(new PublishCollectorPullEventRequest(newEvent));
continue; // pull from the next sensor
}
}
catch (HttpRequestException e)
{
// same handler as for above catch ...
// i guess aggregateException is removed after some update
string message = e.Message;
Console.WriteLine(
$"\nHttp req. exception, message: {message} ... "
+ $"sensor may be down.\n"
+ $"Sensor addr. : {sensorUri.ToString()}\n");
var newEvent = new CollectorPullEvent(
config.serviceId,
sensorUri.ToString(),
false,
0,
e.Message);
// handler for this request is not async
// but i guess it is a good idea to await it anyway
await mediator.Send(new PublishCollectorPullEventRequest(newEvent));
continue; // pull from the next sensor
}
catch (Exception e)
{
Console.WriteLine($"Unexpected exception while pulling data: "
+ $" {e.ToString()}");
continue; // pull from the next sensor
}
if (response == null || !response.IsSuccessStatusCode)
{
// this will continue previous Console.Write( ... );
Console.WriteLine($" bad response ... ");
var newEvent = new CollectorPullEvent(
config.serviceId,
sensorUri.ToString(),
false,
0,
"Sensor returned bad response.");
// handler for this request is not async
// but i guess it is a good idea to await it anyway
await mediator.Send(new PublishCollectorPullEventRequest(newEvent));
continue; // pull from the next sensor
}
string txtContent = await response.Content.ReadAsStringAsync();
// var dataRecords = System
// .Text
// .Json
// .JsonSerializer
// .Deserialize<SensorDataRecords>(txtResponseContent);
// newtonsoft serializes properties to camelCase so when they get
// pulled from sensor system.text.json can't deserialize it because
// class properties are actually in PascalCase, that is the reason
// to use newtonsoft - easier than forcing it to serialize in PascalCase
var dataRecords = JsonConvert
.DeserializeObject <SensorDataRecords>(txtContent);
Console.WriteLine($"returned {dataRecords.RecordsCount} rows ... ");
var pullEvent = new CollectorPullEvent(
config.serviceId,
sensorUri.ToString(),
true,
dataRecords.RecordsCount);
await mediator.Send(new PublishCollectorPullEventRequest(pullEvent));
var addResult = await mediator.Send(
new AddRecordsToSensorRequest(
singleSensor.Name,
dataRecords.CsvHeader,
dataRecords.CsvValues)
);
if (addResult != true)
{
// adding the new records was not successfull
// most possibly database is down ...
// this records will have to be pulled again
continue;
}
// update read index for every sensor that returned records
// at this point lastReadIndex[singleSensor.Name] has to exists
// (look at the beginning of this for loop)
lastReadIndexes[singleSensor.Name] =
alreadyReadCount + dataRecords.RecordsCount;
}
Console.WriteLine($"Tried to pull from: {triedToPullCount} ...");
// 'schedule' the next data pulling
timer.Start();
}
public PublishCollectorPullEventRequest(CollectorPullEvent pullEvent)
{
this.pullEvent = pullEvent;
}
