TrendS
TrendS is a standalone subsystem part of the CGRateS infrastructure, designed to work as an extension of the StatS, by regularly querying it, storing it’s values in a time-series-like database and calculate trend percentages based on their evolution.
Complete interaction with TrendS is possible via CGRateS RPC APIs.
Due it’s real-time nature, TrendS are designed towards high throughput being able to process thousands of queries per second. This is doable since each Trend is a very light object, held in memory and eventually backed up in DataDB.
Processing logic
In order for TrendS to start querying the StatS, it will need to be scheduled to do that. Scheduling is being done using Cron Expressions.
Once Cron Expressions are defined within a TrendProfile, internal Cron Scheduler needs to be triggered. This can happen in two different ways:
- Automatic Query Scheduling
The profiles needing querying will be inserted into trends JSON configuration. By leaving any part of trend_id or tenat empty, it will be interpreted as catch-all filter.
- API Scheduling
The profiles needing querying will be sent inside arguments to the TrendSv1.ScheduleQueries API call.
Offline storage
Offline storage is optionally possible, by enabling profile Stored flag and configuring the store_interval inside JSON configuration.
Trend querying
In order to query a Trend (ie: to be displayed in a web interface), one should use the TrendSv1.GetTrend API call which also offers pagination parameters.
Trend exporting
On each Trend change, it will be possible to send a specially crafted event, TrendUpdate to one of the following subsystems:
- ThresholdS
Sending the TrendUpdate Event gives the administrator the possiblity to react to Trend changes, including escalation strategies offered by the TresholdS paramters. Fine tuning parameters (ie. selecting only specific ThresholdProfiles to increase speed1) are available directly within the TrendProfile.
- EEs
EEs makes it possible to export the TrendUpdate to all the availabe outside interfaces of CGRateS.
Both exporting options are enabled within JSON configuration.
Parameters
TrendS
TrendS is the CGRateS component responsible of generating the Trend queries.
It is configured within trends section from JSON configuration via the following parameters:
- enabled
Will enable starting of the service. Possible values: <true|false>.
- store_interval
Time interval for backing up the trends into DataDB. 0 To completely disable the functionality, -1 to enable synchronous backup. Anything higher than 0 will give the interval for asynchronous backups.
- stats_conns
List of connections where we will query the stats.
- scheduled_ids
Limit the TrendProfiles queried. Empty to query all the available TrendProfiles or just tenants for all the available profiles on a tenant.
- thresholds_conns
Connection IDs towards ThresholdS component. If not defined, there will be no notifications sent to ThresholdS on Trend changes.
- ees_conns
Connection IDs towards the EEs component. If left empty, no exports will be performed on Trend changes.
- ees_exporter_ids
Limit the exporter profiles executed on Trend changes.
TrendProfile
Ís made of the following fields:
- Tenant
The tenant on the platform (one can see the tenant as partition ID).
- ID
Identifier for the TrendProfile, unique within a Tenant.
- Schedule
Cron expression scheduling gathering of the metrics.
- StatID
StatS identifier which will be queried.
- Metrics
Limit the list of metrics from the stats instance queried.
- TTL
Automatic cleanup of the queried values from inside Trend Metrics.
- QueueLength
Limit the size of Trend Metrics. Older values will be removed first.
- MinItems
Issue TrendUpdate events to external subsystems only if MinItems are reched to limit false alarms.
- CorrelationType
The correlation strategy to use when computing the trend. *average will consider all previous query values and *last only the last one.
- Tolerance
Allow a deviation of the values when computin the trend. This is defined as percentage of increase/decrease.
- Stored
Enable storing of this Trend for persistence.
- ThresholdIDs
Limit TresholdProfiles processing the TrendUpdate for this TrendProfile.
Trend
is made out of the following fields:
- Tenant
The tenant on the platform (one can see the tenant as partition ID).
- ID
Unique Trend identifier on a Tenant
- RunTimes
Times when the stat queries were ran by the scheduler
- Metrics
History of the queried metrics, indexed by the query time. One query stores the following values:
Use cases
Aggregate various traffic metrics for traffic transparency.
Revenue assurance applications.
Fraud detection by aggregating specific billing metrics during sensitive time intervals (*acc, *tcc, *tcd).
Building call patterns.
Building statistical information to train systems capable of artificial intelligence.
Building quality metrics used in traffic routing.