Arrivals and Departures for Stop Endpoint numberOfStopsAway

[chrisls121]

Using the Java version of OBA the numberOfStopsAway field is being populated with valid data when querying the arrivals-and-departures-for-stop endpoint. Querying the same endpoint, arrivals-and-departures-for-stop/HSR_355573.json for example, the numberOfStopsAway always shows -1.

Below are the GTFS feeds we are using.

Static Feed
https://opendata.hamilton.ca/GTFS-Static/google_transit.zip

Realtime Feeds
https://opendata.hamilton.ca/GTFS-RT/GTFS_TripUpdates.pb
https://opendata.hamilton.ca/GTFS-RT/GTFS_VehiclePositions.pb
https://opendata.hamilton.ca/GTFS-RT/GTFS_ServiceAlerts.pb

[Ahmedhossamdev]

Hi @chrisls121,
I'll take a look about this.

[Ahmedhossamdev]

Hi @chrisls121 ,

I’ve been working on a fix for this issue and I believe I found the cause of why numberOfStopsAway is always returning -1 in Maglev for the arrivals-and-departures-for-stop endpoint.

I’m currently validating the behavior against the Java OBA implementation and the HSR GTFS/GTFS-RT feeds you shared. I should have a PR up soon for review.

Would also appreciate your feedback once the PR is open, especially to help confirm the behavior matches what you’re seeing in production.

[chrisls121]

Thanks @Ahmedhossamdev, I appreciate your work on this. I would be happy to test once the PR is up.

[Ahmedhossamdev]

Hey @chrisls121,
Do you have an OBA deployment that consumes the HSR feeds and that you use for testing?

[chrisls121]

Hi @Ahmedhossamdev, we do. We are using Maglev as a backend to a small proxy service that adds authentication, caching, and the ability to query arrivals/departures for multiple stops in one call. This data is used to drive digital signage departure displays.

[Ahmedhossamdev]

Hi @chrisls121,

Thanks for the context!

I've opened a draft PR for the fix: #1000

The PR focuses on bringing Maglev's trip status calculations in line with the Java OBA implementation, including numberOfStopsAway, distanceFromStop, and tripStatus. I've been validating the behavior against both the Java server and the HSR GTFS & GTFS-RT feeds.

I also expect to follow up with a few additional PRs focused on performance improvements and cleanup now that the Java parity work is in place.

I'd really appreciate your feedback once you have a chance to test the draft PR, especially since you're using these endpoints in production for your signage displays.

One question: do you happen to have a Java OBA deployment running in production (or another environment) that consumes the HSR feeds? If so, would you be willing to share an endpoint I could test against? It would be very helpful for validating that Maglev's output matches Java OBA as closely as possible.

Thanks!

[chrisls121]

Wow, thanks @Ahmedhossamdev for all your hard work closing the parity gap between the Java OBA and Maglev implementation. I should have some time in the next couple of days to try this out with the HSR data and will report back.

Currently we do not have a Java OBA deployment. We switched over to exclusively using Maglev because we're only using a small subset of functionality/data to drive the signage displays and the Go/SQLite implementation is much more lightweight. We removed the stops away datapoint as a temporary measure.

[Ahmedhossamdev]

Thanks, @chrisls121 ! I'll put the PR on hold for now and wait for your feedback after you've had a chance to test it with the HSR data.

[aaronbrethorst]

Hey @chrisls121 - I'd love to learn a bit more about your use case and see how we might structure our Maglev roadmap to take some/all of these responsibilities off your plate:

We are using Maglev as a backend to a small proxy service that adds authentication, caching, and the ability to query arrivals/departures for multiple stops in one call. This data is used to drive digital signage departure displays.

can you email me at aaron@onebusaway.org? also cc @burma-shave

[chrisls121]

Hey @aaronbrethorst. Thanks for your interest in our implementation of Maglev. I've sent you an E-Mail with the details.

[Ahmedhossamdev]

Hi @chrisls121 ,
Just following up, have you had a chance to test this with the HSR data? Any updates?

[chrisls121]

Hi @Ahmedhossamdev We have been running this for a few days and it has been working great.

[Ahmedhossamdev]

Hey @chrisls121
That's great to hear! 🎉
I'm also working on some additional improvements, so make sure to keep pulling the latest updates. I'm planning to get this PR merged soon.