5 min read

Package Java Spring Boot service into rpm

April 12, 2019

This post is a follow-up to my last post The final rpm packaging guide. What I did not cover in the “final” guide was how to deal with the common case of packaging a service. In this post we are going to build a simple java spring boot application and package it as a systemd service into an rpm.

To get started I recommend to walk through the test setup section of my last post.

Requirements

To accomplish this tutorial a few dev tools must be installed.

httpie - Modern alternative to wget and curl.

sudo yum install httpie

rpmbuild - Utility to build rpms.

sudo yum install rpm-build

rpmdev - Dev utilities to build rpms.

sudo yum install rpmdevtools

rpmlint - Tool for checking common errors in rpm packages.

sudo yum install rpmlint

Example Application

We assume that we want to deploy a spring boot application.

Lets create one from the spring boot getting started source.

Checkout the official getting started repository.

cd ~ && git clone https://github.com/spring-guides/gs-spring-starter.git

Navigate into the project.

gs-spring-starter/initial

Then build and run the jar file.

./gradlew build && java -jar build/libs/gs-spring-starter-0.1.0.jar

Check if you get a response from the spring boot service.

http GET localhost:8080

It should return:

HTTP/1.1 200 
Content-Length: 27
Content-Type: text/plain;charset=UTF-8
Date: Fri, 12 Apr 2019 07:28:37 GMT

Greetings from Spring Boot!

Project Setup

Create the initial rpm folder structure.

cd ~; mkdir rpmbuild; cd ~/rpmbuild; rpmdev-setuptree

Copy the jar file into the source folder.

cp ../gs-spring-starter/initial/build/libs/gs-spring-starter-0.1.0.jar SOURCES/

Our example service will be managed by systemd and thus we also have to package a service file into the rpm.

Create the file vim SOURCES/spring-starter.service with the following content:

[Unit]
Description=Spring Starter
After=network-online.target

[Service]
Type=simple
WorkingDirectory=/var/opt/spring-starter
ExecStart=/usr/bin/java -jar /usr/local/spring-starter/gs-spring-boot.jar
Restart=on-abort
User=spring-starter
Group=spring-starter

[Install]
WantedBy=multi-user.target

And thats it.

Write the Spec

The spec file defines the rpm build process and installation procedure.

Create a spec file for our spring starter application.

vim SPECS/spring-starter.spec

And set the following content:

##### HEADER SECTION #####

Name:           spring-starter
Version:        0.1.0
Release:        0
Summary:        Rpm package for Spring Starter

License:        ASL 2.0
URL:            https://spring.io
Source0:        gs-spring-boot-%{version}.jar
Source1:				%{name}.service

Requires:       shadow-utils,bash
BuildRequires:	systemd
%{?systemd_requires}

BuildArch:      noarch

%description
%{summary}

# disable debuginfo, which is useless on binary-only packages
%define debug_package %{nil}

# do not repack jar files
%define __jar_repack %{nil}

##### PREPARATION SECTION #####
%prep

# empty section

##### BUILD SECTION #####
%build

# empty section

##### PREINSTALL SECTION #####
%pre

# create Spring Starter service group
getent group spring-starter >/dev/null || groupadd -f -g 30000 -r spring-starter

# create Spring Starter service user
if ! getent passwd spring-starter >/dev/null ; then
    if ! getent passwd 30000 >/dev/null ; then
      useradd -r -u 30000 -g spring-starter -d /home/spring-starter -s /sbin/nologin -c "Spring Starter service account" spring-starter
    else
      useradd -r -g spring-starter -d /home/spring-starter -s /sbin/nologin -c "Spring Starter service account" spring-starter
    fi
fi
exit 0

##### INSTALL SECTION #####
%install

app_dir=%{buildroot}/usr/local/spring-starter
data_dir=%{buildroot}/var/opt/spring-starter
service_dir=%{buildroot}/%{_unitdir}

# cleanup build root
rm -rf %{buildroot}
mkdir -p  %{buildroot}

# create app folder
mkdir -p $app_dir

# create data folder
mkdir -p $data_dir

# create service folder
mkdir -p $service_dir

# copy all files
cp %{SOURCE0} $app_dir/gs-spring-boot.jar
cp %{SOURCE1} $service_dir

##### FILES SECTION #####
%files

# define default file attributes
%defattr(-,spring-starter,spring-starter,-)

# list of directories that are packaged
%dir /usr/local/spring-starter
%dir %attr(660, -, -) /var/opt/spring-starter

# list of files that are packaged
/usr/local/spring-starter/gs-spring-boot.jar
/usr/lib/systemd/system/%{name}.service

##### POST INSTALL SECTION #####
%post

# ensure Spring Starter service is enabled and running
%systemd_post %{name}.service
%{_bindir}/systemctl enable %{name}.service
%{_bindir}/systemctl start %{name}.service

##### UNINSTALL SECTION #####
%preun

# ensure Spring Starter service is disabled and stopped
%systemd_preun %{name}.service

%postun

case "$1" in
	0) # This is a package remove

		# remove app and data folders
		rm -rf /usr/local/spring-starter
		rm -rf /var/opt/spring-starter

		# remove Spring Starter service user and group
		userdel spring-starter
	;;
	1) # This is a package upgrade
		# do nothing
	;;
esac

# ensure Spring Starter service restartet if an upgrade is performed
%systemd_postun_with_restart %{name}.service

##### CHANGELOG SECTION #####
%changelog

* Wed Mar 20 2019 Janik vonRotz <contact@janikvonrotz.ch> - 0.1.0-0
- First spring-starter package

I wont go into details about the spec as I already did that in my last post. Not much has changed. However, one thing worth to mention is the %define __jar_repack %{nil} definition. This options disables the compression for .jar files. If the jar file is compressed it becomes inexecutable.

Further, as you might have noticed there are systemd macros, which ensure the service is configured properly. In the post install section two additional commands have been added to enable and start the service. This was done because t the systemd macros do not enable or start service by default.