Add Docker container with OpenTripPlanner on Java 21 LTS

[Copilot]

Summary

Provides Docker containerization for OpenTripPlanner 2.5.0 running on Eclipse Temurin Java 21 JRE with exposed API on port 8080.

Issue

Addresses the need to run OTP as a containerized service accessible to external applications.

Implementation:

• Dockerfile: Eclipse Temurin 21-jre base, downloads OTP 2.5.0, entrypoint script for runtime JAVA_OPTS configuration
• docker-compose.yml: Service definition with volume mounting for GTFS/OSM data at ./data
• Configuration: Default 4GB heap via JAVA_OPTS environment variable, configurable at runtime
• Documentation: Setup instructions, API usage examples, data preparation guide

Technical approach:

• Entrypoint script enables JVM memory tuning without image rebuild
• Volume mount at /var/otp/graphs for transit data persistence
• Default command: --load /var/otp/graphs --serve for graph building and API serving

Unit tests

No unit tests required - infrastructure configuration only. Manual verification:

• Image builds successfully (470MB)
• Java 21 LTS runtime confirmed
• OTP 2.5.0 JAR functional
• JAVA_OPTS environment variable applies at runtime
• Docker Compose configuration validated

Documentation

• README with quickstart, configuration, API usage, troubleshooting
• data/README.md explaining GTFS and OSM file requirements
• .env.example showing supported configuration options
• Inline comments in Dockerfile explaining SSL handling for CI environments

Changelog

Include in changelog - adds Docker deployment capability for OTP.

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

• docs.opentripplanner.org
  • Triggering command: curl -s REDACTED (dns block)

If you need me to access, download, or install something from one of these locations, you can either:

• Configure Actions setup steps to set up my environment, which run before the firewall is enabled
• Add the appropriate URLs or hosts to the custom allowlist in this repository's Copilot coding agent settings (admins only)

Original prompt

Please create a Docker container with an instance of OpenTripPlanner (OTP). The purpose is to expose OTP's API for requests from different services.

As a Java program, OTP must be run within a Java virtual machine (JVM), which is provided as part of the Java runtime (JRE) or Java development kit (JDK). We recommend running on Java 21 rather than a later version, as it is a long-term support release.

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