epicsoft/tomcat repository overview

⁠Tomcat

This Docker image is managed and kept up to date by epicsoft LLC⁠.

The official tomcat⁠ image, extended by one feature: Docker environment variables with the prefix APP_ are passed to the application as system properties.

• Base image: https://hub.docker.com/_/tomcat⁠, platform linux/amd64
• Dockerfile: https://gitlab.com/epicsoft-networks/tomcat/-/blob/main/Dockerfile⁠
• Repository: https://gitlab.com/epicsoft-networks/tomcat⁠, mirrored to GitHub⁠ — issues are welcome on both; code changes only as merge requests on GitLab, the mirror overwrites anything pushed to GitHub
• Container registry: https://gitlab.com/epicsoft-networks/tomcat/container_registry⁠
• Docker Hub: https://hub.docker.com/r/epicsoft/tomcat⁠
• Changelog: https://gitlab.com/epicsoft-networks/tomcat/-/blob/main/CHANGELOG.md⁠
• License: MIT

⁠Description

⁠TL;DR - for technicians

Docker environments                              Tomcat App environments
  - APP_DATABASE_NAME="exampleDatabaseName"        - app.database.name=exampleDatabaseName
  - APP_CUSTOM_ENV1=Hello from Docker 1            - app.custom.env1=Hello from Docker 1
  - APP_CUSTOM_ENV2="Hello from Docker 2"          - app.custom.env2=Hello from Docker 2
  - APP_CUSTOM_ENV3='Hello from Docker 3'          - app.custom.env3=Hello from Docker 3
                                                 example for use in configuration: ${app.database.name}

⁠A little more detailed

All environments with the prefix APP_ are passed on to the application.
The environment variable can be used in the application or configuration.
The name of the environment variable is written in lower case and separated with dots . instead of underscores _, for example APP_DATABASE_NAME is called app.database.name in the application or configuration.

Example for use in configuration: ${app.database.name}.

Single ' and double " quotation marks can be used in Docker environments, these are removed for transfer to the application.
Only a matching pair around the whole value is removed, a value like he said "hi" keeps its quotation marks.
Apart from that the value is passed on unchanged, a $, a backtick or a $(...) in a value stays what it is and is never executed.

After the prefix APP_ the name may only contain letters, digits and underscores _.
An environment like APP_MY NAME cannot become a property name, it is ignored and a line is written to the log.
Upper and lower case are both accepted, app_database_name works like APP_DATABASE_NAME.

If you use your own setenv.sh file and still use the functionality of the Docker environments, then add the following line to your own setenv.sh file.

source $(dirname "$0")/dockerenv.sh

⁠Versions

latest based on tomcat:latest - build weekly

11.0-jre25 based on tomcat:11.0-jre25 - build weekly

11.0-jre21 based on tomcat:11.0-jre21 - build weekly

10-jre25 based on tomcat:10-jre25 - build weekly

10-jre21 based on tomcat:10-jre21 - build weekly

10-jre17 based on tomcat:10-jre17 - build weekly

10-jre11 based on tomcat:10-jre11 - build weekly

9-jre25 based on tomcat:9-jre25 - build weekly

9-jre21 based on tomcat:9-jre21 - build weekly

9-jre17 based on tomcat:9-jre17 - build weekly

9-jre11 based on tomcat:9-jre11 - build weekly

9.0-jre11 based on tomcat:9.0-jre11 - build weekly

All versions match the base image. If you need more, just ask.

A tag is the version: it names the Tomcat and the JRE in the image, and it is rebuilt weekly, so it follows the official image.
Which versions an image really holds is written into it.

docker image inspect --format '{{index .Config.Labels "image.tomcat.version"}}' epicsoft/tomcat:11.0-jre21
docker image inspect --format '{{index .Config.Labels "image.java.version"}}' epicsoft/tomcat:11.0-jre21

Changes to this image are recorded in the changelog⁠.

⁠Examples

⁠Example use in a docker-compose file

docker-compose.yml

services:
  tomcat:
    image: epicsoft/tomcat:latest
    container_name: tomcat
    hostname: tomcat
    restart: unless-stopped
    environment:
      - APP_DATABASE_NAME="exampleDatabaseName"
      - APP_CUSTOM_ENV1=Hello from Docker 1
      - APP_CUSTOM_ENV2="Hello from Docker 2"
      - APP_CUSTOM_ENV3='Hello from Docker 3'
    volumes:
      - /srv/tomcat/webapps:/usr/local/tomcat/webapps:rw
      - /etc/localtime:/etc/localtime:ro
      - /etc/timezone:/etc/timezone:ro
    tmpfs:
      - /usr/local/tomcat/temp:exec,mode=777,uid=0,gid=0
    networks:
      - tomcat
    ports:
      - "8080:8080"
networks:
  tomcat:
    name: tomcat

Tomcat logs (shortened / sequence of rows does not have to match)

INFO [main] ...catalina...log Command line argument: -Dapp.database.name=exampleDatabaseName
INFO [main] ...catalina...log Command line argument: -Dapp.custom.env1=Hello from Docker 1
INFO [main] ...catalina...log Command line argument: -Dapp.custom.env2=Hello from Docker 2
INFO [main] ...catalina...log Command line argument: -Dapp.custom.env3=Hello from Docker 3

⁠Example of using your own setenv.sh

docker-compose.yml (shortened)

volumes:
  - /srv/tomcat/setenv.sh:/usr/local/tomcat/bin/setenv.sh:ro

setenv.sh

#!/bin/bash

# <CUSTOM CODE>

#### Load Docker environments
source $(dirname "$0")/dockerenv.sh

⁠Reporting problems

Issues are welcome on GitLab⁠ and GitHub⁠. Please report a security problem as a confidential issue on GitLab instead of a public one.

⁠License

MIT⁠ — Copyright (c) 2024-2026 epicsoft LLC / Alexander Schwarz

The MIT license applies only to files created by epicsoft LLC. Third-party software in the image — Apache Tomcat, the JRE and the official tomcat image — remains under its own licenses.