Stock Apache Tomcat and Gradle on OpenShift

For my ongoing work on Tangram a wanted to use the RedHat OpenShift platform. In this post I'm going to outline the generic part of this which now is extracted as a Quickstart on github via https://github.com/mgoellnitz/openshift-tomcat-gradle-quickstart.
The requirements where the following: Build must be possible with Gradle and a plain Apache Tomcat webcontainer - not a JBoss Tomcat derivative - is needed. For the time being I still left out the option to use Jenkins, since the way to re-deploy on git-push OpenShift gives me, is quite usable.
So this results in the idea of a combination of the work of Shekhar Gulati at https://www.openshift.com/blogs/run-gradle-builds-on-openshift with the code at https://github.com/shekhargulati/gradle-openshift-quickstart and the tomcat Quickstart https://github.com/openshift-quickstart/openshift-tomcat-quickstart
Looking at the changes needed to use Gradle, I decided to integrate them manually and modify them along the way. Also the Tomcat Quickstart will not be used directly but serves as a template, since I don't want to pull the Apache Tomcat binaries into the git repository. As opposed to many other examples I came across, the installation of the RedHat cloud command line tools is completely left out. You might want to use them, but they are not needed for this example.
First of all I had to create an application (named "test") and had to take "DIY 0.1" as the type of application and clone the resulting repository.

git clone ssh://524e65...094@test-application.rhcloud.com/~/git/test.git/
cd test

This repository resembles the working directories of your application on OpenShift and is not just a development set of folders. So you will find some scripts here to interact with the infrastructure of OpenShift. These scripts have to be customized to fetch and configure Apache Tomcat and Gradle.
Now it's time to add script element to fetch the tool.

# .openshift/action_hooks/build:

# gradle build
set -x

DIR=`pwd`

# obtain tomcat
export TOMCAT_VERSION=7.0.61
if [ ! -f $OPENSHIFT_DATA_DIR/apache-tomcat-${TOMCAT_VERSION}.tar.gz ] ; then
  wget http://apache.../v${TOMCAT_VERSION}/bin/apache-tomcat-${TOMCAT_VERSION}.tar.gz
fi
if [ -f $OPENSHIFT_DATA_DIR/apache-tomcat-${TOMCAT_VERSION}.tar.gz ] ; then
  rm -rf tomcat
  tar xvzf $OPENSHIFT_DATA_DIR/apache-tomcat-${TOMCAT_VERSION}.tar.gz
  mv apache-tomcat-${TOMCAT_VERSION} tomcat
  cd $OPENSHIFT_DATA_DIR/tomcat
  rm -rf logs
  ln -s $OPENSHIFT_LOG_DIR logs
  cd $OPENSHIFT_DATA_DIR
fi

# obtain gradle
export GRADLE_VERSION=2.2.1
if [ ! -d $OPENSHIFT_DATA_DIR/gradle-${GRADLE_VERSION} ] ; then
  cd $OPENSHIFT_DATA_DIR
  wget http://services.gradle.org/distributions/gradle-${GRADLE_VERSION}-bin.zip
  unzip gradle-${GRADLE_VERSION}-bin.zip
  rm -f gradle-${GRADLE_VERSION}-bin.zip
fi

cd $DIR

cd $OPENSHIFT_REPO_DIR
export GRADLE_USER_HOME=${OPENSHIFT_DATA_DIR}gradle
export GRADLE_HOME=${OPENSHIFT_DATA_DIR}gradle-${GRADLE_VERSION}
export PATH=$GRADLE_HOME/bin:$PATH
if [ -f openshift-build.gradle ] ; then
 gradle --stacktrace -b build.gradle clean build
fi

Use at least version 2.2 of Gradle due to http://issues.gradle.org/browse/GRADLE-2871. Also Gradle needs some local directory on the target host.


# .openshift/action_hooks/pre_build:
 
# gradle storage dir build
set -x

if [ ! -d $OPENSHIFT_DATA_DIR/gradle ] ; then
  mkdir $OPENSHIFT_DATA_DIR/gradle
fi

The default stop action hook script contains some references on a ruby server and is missing a nice tomcat handling.


# .openshift/action_hooks/stop:
source $OPENSHIFT_CARTRIDGE_SDK_BASH

# The logic to stop your application should be put in this script.
if [ -z "$(ps -efww | grep tomcat | grep -v grep)" ] ; then
  client_result "Tomcat is already stopped"
else
  if [ -x $OPENSHIFT_DATA_DIR/tomcat/bin/shutdown.sh ] ; then
    $OPENSHIFT_DATA_DIR/tomcat/bin/shutdown.sh
  else
    kill `ps -efww | grep tomcat | grep -v grep | awk '{ print $2 }'` > /dev/null 2>&1
  fi
fi
exit 0


For safety reasons it might be a good idea to delete unexploded wars from the webapp directory of the tomcat installation


# .openshift/action_hooks/deploy:
set -x

# Addition:
for i in `ls $OPENSHIFT_DATA_DIR/tomcat/webapps/*.war`; do
  dn=`basename $i .war`
  echo "removing $dn"
  rm -rf $OPENSHIFT_DATA_DIR/tomcat/webapps/$dn
done

The start script has to be modified not to use ruby but the tomcat installation


# .openshift/action_hooks/start:
set -x
cp -rdp ${OPENSHIFT_REPO_DIR}/tomcat/conf/* ${OPENSHIFT_DATA_DIR}/tomcat/conf/
cp -rdp ${OPENSHIFT_REPO_DIR}/tomcat/lib/* ${OPENSHIFT_DATA_DIR}/tomcat/lib/
cp -rdp ${OPENSHIFT_REPO_DIR}/tomcat/webapps/* ${OPENSHIFT_DATA_DIR}/tomcat/webapps/cd $OPENSHIFT_DATA_DIR/tomcat
sed -ig 's/OPENSHIFT_DIY_IP/'$OPENSHIFT_DIY_IP'/g' conf/server.xml
sed -ig 's/OPENSHIFT_APP_DNS/'$OPENSHIFT_APP_DNS'/' conf/server.xml
bin/startup.sh

After these preparation steps it would be time to integrate your application by providing a build.gradle script in the root path and all the needed source files.
When using a custom domain, let this domain point to your Applications hostname via a DNS CNAME record. Then create an alias with your domain name for the application using the RedHat Cloud command line tool. (Or create the alias via the console web application) Don't forget to add this domain name to your server.xml override.