docker

name	docker
description	Use for Dockerfile and container runtime changes in telegram-home-bot: Raspberry Pi/Linux runtime, fping/iproute2, Gradle bootJar, network mode, ports, logs.

Docker Skill

Context

This project has a single Dockerfile for building a container image. The application is designed to run on Raspberry Pi (ARM) and Linux.

Dockerfile

FROM openjdk:11-jre-slim-buster
ENV SERVER_PORT=8080
EXPOSE ${SERVER_PORT}
WORKDIR application
COPY build/libs/*.jar app.jar
RUN apt-get update && \
    apt-get -y install fping &&  \
    apt-get -y install iproute2 &&  \
    apt-get clean
ENTRYPOINT ["java", "-jar","./app.jar"]

Build & Run Commands

# Build JAR first
./gradlew clean bootJar

# Build Docker image
docker build -t thb-image .

# Run container (bridge network — host network scanning works)
docker run -d -p 80:8080 --network=bridge --name=thb thb-image

# Start/stop
docker start thb
docker stop thb

# View logs
docker logs -f thb

Key Notes

System Dependencies

The image installs:

• fping — required for broadcast ping network scanning
• iproute2 — required for ip -j n show (ARP table queries)

Network Mode

• Use --network=bridge for container-to-host network visibility
• Host network mode (--network=host) can also be used for full LAN access

Port Mapping

• Container exposes port 8080 (overridden from default 9988 via SERVER_PORT=8080)
• Map to any host port: -p 80:8080 in examples

Java Version

• Dockerfile uses OpenJDK 11 (JRE slim), but the project compiles with JDK 17
• Ensure compatibility or update the base image if needed

Do NOT

• Do NOT add new system packages to Dockerfile without clear necessity
• Do NOT change the WORKDIR from application without updating COPY and ENTRYPOINT
• Do NOT remove apt-get clean — it reduces image size
• Do NOT hardcode the JAR filename — the wildcard *.jar is intentional