seredkin / scheduler

Public Transportation Scheduler implementation

Scheduler NanoService

An implementation of basic query API for retrieving data of a public transportation service.

Technologies

• Kotlin
• Gradle
• Micronaut Framework [https://micronaut.io/]
• JUnit
• Docker
• Postman

External dependencies

• Commons-codec
• Hamcrest

Concepts

• Lines

  • Three public transportation lines operate the city
  • Each line has more than 2 stops
  • Lines may share stops with each other (transit stations)

• Stops

  • Each stop has an unique identifier
  • Each stop has an unique pair of integers (X,Y) as its coordinates

• Timing data

  • TimeOfDay uses ISO LocalDate format '09:55:59'
  • For each Stop at a given time of the day, there is one or more services available
  • Delays are dynamic information on the current state of each line

Open Issues

• Multi-tenancy support is missing from the design. Would be nice to serve multiple cities with the same instance.
• DataSet versioning: we should be able to restore the state of stop graph/timetables/delays at any moment of time in the past.
• Direction information for lines and times is missing
• Timing data domain should be specified properly:
  • Arrival/Departure time
  • Scheduled/Expected/Actual times should follow this concept:
    • ExpectedArrivalDelay: delta between ScheduledArrival and ExpectedArrival
    • ActualArrivalDelay: delta between ScheduledArrival and ActualArrival
    • Deltas can be negative if service arrives/departs ahead of the schedule
  • Transit time for transit stations
• Delay information per vehicle might be a better option
• Calendar of working days/holidays, service maintenance/shutdowns is missing
• Potentially useful options:
  • Transit stations should have accessibility and transit time data
  • Lines should have accessibility data: stair-less access, bicycles allowed etc...

Rest API

The container image contains a reference data set suitable for testing and prototyping. Call

Docker

• build with 'docker build .' and notice the container id in the console output: Successfully built 2a54babf60c4
• run with docker run -p8081:8081 2a54babf60c4 whereas last parameter it the image name

Postman

Use postman script to test running container by importing this file to Postman:

Postman Example: [https://github.com/seredkin/scheduler/blob/master/postman-screenshot.png]

Postman collection: [https://github.com/seredkin/scheduler/blob/master/scheduler.postman_collection.json]

Add your own Postman requests

Development

Open build.gradle in our IDE of choice, set up annotation processing for Micronaut:

[https://guides.micronaut.io/creating-your-first-micronaut-app-kotlin/guide/index.html]

By running all test with coverage, you should get ˜90% line coverage (approximation is given to current inability of IDEA to evaluate Kotlin coverage properly):

Coverage example: [https://github.com/seredkin/scheduler/blob/master/coverage-screenshot.png]