Metric: Vehicle Postion Validation

[Hasaber8]

Vehicle Position Validation Metrics

Description

Add metrics to track the validity of vehicle positions from GTFS-RT feeds. This helps transit agencies identify data quality issues in their real-time vehicle position feeds.

Background

The original Java Watchdog included position validation, but the Go version needs to implement this using only public GTFS-RT feeds without requiring internal server access.

Implementation Details

Data Source

• GTFS-RT Vehicle Positions feed
• Accessed via: server.VehiclePositionUrl configuration

New Prometheus Metrics

1. invalid_vehicle_positions_count_gtfs_rt

   • Type: Gauge
   • Labels: gtfs_rt_url, server_id
   • Description: Number of invalid vehicle positions (invalid lat/lon) in the GTFS-RT feed

2. valid_vehicle_positions_percent_gtfs_rt

   • Type: Gauge
   • Labels: gtfs_rt_url, server_id
   • Description: Percentage of valid vehicle positions in the GTFS-RT feed

Validation Rules

• Latitude must be between -90 and 90 degrees
• Longitude must be between -180 and 180 degrees