private string GetSeriesNames(IEnumerable<string> sensorSerials, ReadingsFetchFilter filter)
{
var seriesNames = sensorSerials.Select(p => GetSeriesName(p, filter)).Distinct();
return String.Join(", ", seriesNames);
}
/// <summary>
/// Fetches readings for single or multiple sensores in a batched query. If the batched query fails,
/// a fallback query which fetches readings sensor per sensor will get executed.
/// </summary>
/// <param name="filter">Fetch filter.</param>
/// <returns></returns>
public async Task<IList<Serie>> GetReadings(ReadingsFetchFilter filter)
{
IList<Serie> seriesResults = new List<Serie>();
var errorOccured = false;
try
{
var query = GetQuery(filter.SensorSerials, filter);
var result = await QueryReading(query);
seriesResults = result.ToList();
}
catch (Exception e)
{
errorOccured = true;
}
if (errorOccured)
seriesResults = await GetReadingsOneByOneFallback(filter);
seriesResults.ToList().ForEach(CleanUpSensorSerial);
return seriesResults;
}
private string GetSeriesName(string sensorSerial, ReadingsFetchFilter filter)
{
var isResolutionQuery = IsResolutionQuery(filter.Resolution);
var seriesName = String.Format("{0}.{1}", _influxDbReadingSeries, sensorSerial);
if (isResolutionQuery)
seriesName = String.Format("{0}.{1}", filter.Resolution, seriesName);
return seriesName;
}
/// <summary>
/// Gets base query for fetching sensors.
///
/// NOTE: SHOULD ONLY BE CALLED FROM GetQuery methods, and not any other "higher-level" methods from the chain.
/// </summary>
/// <param name="seriesToQuery">Series to query already prepared as a comma delimited string array.</param>
/// <param name="filter">Readings fetch filter.</param>
/// <returns>Base query string.</returns>
private string GetBaseQuery(string seriesToQuery, ReadingsFetchFilter filter)
{
return String.Format("select {0} from {1} where time > '{2}' and time < '{3}'", filter.Metric, seriesToQuery, filter.TimeFrom, filter.TimeTo);
}
private string GetQuery(IEnumerable<string> sensorSerials, ReadingsFetchFilter filter)
{
var seriesNames = GetSeriesNames(sensorSerials, filter);
return GetBaseQuery(seriesNames, filter);
}
private string GetQuery(string sensorSerial, ReadingsFetchFilter filter)
{
var seriesName = GetSeriesName(sensorSerial, filter);
return GetBaseQuery(seriesName, filter);
}
/// <summary>
/// Fetches readings sensor per sensor. If fetch is for a single sensor, it will rethrow the exception, if not,
/// it will return, an empty Serie List. Because of this, batched queries will not "fail". They simply won't
/// include readings for that sensor (for example on custom charts, or in AQR report). In case of a single sensor
/// fetch - we actually want to know that the sensor is "faulty".
/// </summary>
/// <param name="filter">Fetch filter.</param>
/// <returns>Async task which returns a list of seies.</returns>
private async Task<IList<Serie>> GetReadingsOneByOneFallback(ReadingsFetchFilter filter)
{
IList<IList<Serie>> seriesList = new List<IList<Serie>>();
var isSingleFetch = filter.SensorSerials.Count() == 1;
foreach (var sensorSerial in filter.SensorSerials)
{
var query = GetQuery(sensorSerial, filter);
try
{
var series = await QueryReading(query);
seriesList.Add(series.ToList());
}
catch (Exception)
{
if (isSingleFetch)
{
throw;
}
else
{
seriesList.Add(new List<Serie>());
}
}
}
return FlattenSeriesResult(seriesList);
}