OneBusAway Watchdog

OneBusAway Watchdog is a simple framework for retrieving metrics about schedule and realtime data. When hosting OneBusAway, it is convenient to know information about the realtime data, and perhaps to even set alarms should the data fall outside what is expected.

Design

The idea is simple, for each metric of concern a webservice is created that exposes that data in a readily queryable format. Take for example a common issue with realtime feeds, counting the number of tripIds that were received but not matched to the current transit data bundle. By making a GET request on the webservice below:

onebusaway-watchdog-webapp/api/metric/realtime/trip/{agencyId}/unmatched

Returns:

{
  "currentTimestamp":1402402125238,
  "metricName":"unmatched-trips",
  "metricValue":1,
  "response":"SUCCESS",
  "errorMessage":null
}

Here, the agencyId is what is configured in the transit data bundle (e.g., 1). The metricValue property contains the response, indicating that for the last update from the realtime feed, we received one tripId that did not match to the bundle. The metricValue property should only be considered when the response property is populated with SUCCESS. Should the response not be a SUCCESS, the errorMessage property may be populated with a descriptive reason of the failure.

Metrics

Below is a table of webservices that have been implemented. Adding another metric is trivial, it simply requires extending MetricResource.

URL	Result (metricValue)	Notes
http://developer.onebusaway.org/onebusaway-watchdog-webapp/api/metric/ping	1 if the service is up and the bundle loaded properly	Sanity check on configuration
Agency - Schedule
http://developer.onebusaway.org/onebusaway-watchdog-webapp/api/metric/schedule/agency/total	Count of agencies loaded in current bundle	See agency-id-list for more details
http://developer.onebusaway.org/onebusaway-watchdog-webapp/api/metric/schedule/agency/id-list	Array of agencyIds loaded from current bundle	Exposes currently configured agencies.
Trip - Schedule
http://developer.onebusaway.org/onebusaway-watchdog-webapp/api/metric/schedule/trip/1/total	Count of scheduled trips Per agency .
Agency - Realtime
http://developer.onebusaway.org/onebusaway-watchdog-webapp/api/metric/realtime/agency/1/last-update-delta	Seconds elapsed since last successful update	An update may require non-zero update records to be considered successful
Trip - Realtime
http://developer.onebusaway.org/onebusaway-watchdog-webapp/api/metric/realtime/trip/1/total	Count of records included in the last realtime update	Updates may contain multiple vehicles, do not associate this with trip or vehicle counts
http://developer.onebusaway.org/onebusaway-watchdog-webapp/api/metric/realtime/trip/1/matched	Count of realtime trips that were matched to scheduled trips (found in bundle)	Counterpart to unmatched-trips
http://developer.onebusaway.org/onebusaway-watchdog-webapp/api/metric/realtime/trip/1/unmatched	Count of trip Ids not found in current bundle	See unmatched-trip-ids for offending trips
http://developer.onebusaway.org/onebusaway-watchdog-webapp/api/metric/realtime/trip/1/unmatched-ids	Array of tripIds not found in bundle	Search for these tripIds in agency provided bundle and report to agency.
http://developer.onebusaway.org/onebusaway-watchdog-webapp/api/metric/realtime/trip/1/schedule-realtime-delta	(Count of scheduled trips ) - (Count of realtime trips from last update)	See buses-in-service-percent for percentage version of this metric
http://developer.onebusaway.org/onebusaway-watchdog-webapp/api/metric/realtime/trip/1/buses-in-service-percent	(count of realtime trips / count of scheduled trips) * 100	Reports percentages of realtime buses matched to schedule
Stop - Realtime
http://developer.onebusaway.org/onebusaway-watchdog-webapp/api/metric/realtime/stop/1/unmatched	Count of stop Ids not found in current bundle	See unmatched-stop-ids for offending stopIds
http://developer.onebusaway.org/onebusaway-watchdog-webapp/api/metric/realtime/stop/1/unmatched-ids	Array of stopIds not found in bundle	Search for these stopIds in agency provided bundle and report to agency
http://developer.onebusaway.org/onebusaway-watchdog-webapp/api/metric/realtime/stop/1/matched	Count of stop Ids matched to the current bundle
Location - Realtime
http://developer.onebusaway.org/onebusaway-watchdog-webapp/api/metric/realtime/location/1/total	Count of coordinates reported for Id
http://developer.onebusaway.org/onebusaway-watchdog-webapp/api/metric/realtime/location/1/invalid	Count of coordinates not inside agency bounding box	Bounding box is defined from bundle
http://developer.onebusaway.org/onebusaway-watchdog-webapp/api/metric/realtime/location/1/invalid-lat-lons	Array of invalid lat/lons