Maven & Git: Releases and Hotfixes

When you write an application you want a simple way to release a new major version, but also to release bugfixes (here i call them hotfixes) to a released version. If you write Java applications, chances are, you are using Maven and then as a source control you might be using GIT. Maven offers a nice way to set versions, and Git makes it easy to create releases and tags.

I personally use the git branch model described by Vincent Griessen. There development is done on the develop branch, and when a release is done, then a release branch is created. This branch is called release/x.x.x. There the version is updated and a tag is created from this release. If you then create a hotfix, you do that on this release branch, create the new tag, and then merge those changes back down to the develop branch (and perhaps any feature branches).

I have created to scripts which help you to easily create these releases and hotfixes.

release.sh: This is the first script to do a release. It’s input is the source branch, mostly develop, and the version to created. It will create a new release/x.x.x branch, create a temp branch to create the tag, create the tag, cleanup and then push to remote:

#!/bin/bash

# usage
if [ $# != 2 ] ; then
 echo -e "Usage: ${0} <source_branch> <version>"
 exit 1
fi

# Confirm
sourceBranch=${1}
releaseVersion=${2}
echo -e "INFO: Do you want to release version ${releaseVersion} from branch ${sourceBranch}? y/n"
read a
if [[ "${a}" != "y" && "${a}" != "Y" ]] ; then
 exit 0;
fi

# validate tag and release branch do not exist
echo -e "INFO: Fetching tags and branches and validating they do not exist..."
if ! git fetch --all --tags > /dev/null ; then
 echo -e "ERROR: Tags and branches could not be fetched!"
 exit 1
fi
if git tag | grep "${releaseVersion}" > /dev/null ; then
 echo -e "ERROR: Tag already exists!"
 exit 1
fi
if git branch --all | grep "release/${releaseVersion}" > /dev/null ; then
 echo -e "ERROR: Tag already exists!"
 exit 1
fi

# validate tag does not exist
if git tag | grep "${releaseVersion}" > /dev/null ; then
 echo -e "ERROR: Tag already exists!"
 exit 1
fi

# make sure gpg-agent is available and loaded
echo -e "\nINFO: Searching for gpg-agent..."
if ! which gpg-agent ; then
 echo -e "ERROR: gpg-agent missing!"
fi
if ! gpg-agent 2>&1 | grep "running and available" ; then
 echo -e "WARN: gpg-agent not running, trying to start..."
 if ! gpg-agent --daemon ; then
 echo -e "ERROR: Failed to initialize gpg-agent, please make sure it is up and running before continuing!"
 exit 1
 fi
 if ! gpg-agent 2>&1 | grep "running and available" ; then
 echo -e "ERROR: Failed to initialize gpg-agent, please make sure it is up and running before continuing!"
 exit 1
 fi
fi

# Checkout source branch
echo -e "\nINFO: Checking out source branch ${sourceBranch}"
if ! git checkout ${sourceBranch} ; then
 echo -e "ERROR: Failed to checkout branch ${sourceBranch}"
 exit 1
fi

# create new release branch, and temp tag
echo -e "\nINFO: Creating release and temp branches..."
if ! git checkout -b release/${releaseVersion} ; then 
 echo -e "ERROR: Failed to create release branch!"
 exit 1
fi
if ! git checkout -b temp ; then
 echo -e "ERROR: Failed to create temp branch!"
 exit 1
fi

# set release version
echo -e "\nINFO: Setting version..."
if ! mvn versions:set -DgenerateBackupPoms=false -DnewVersion=${releaseVersion} > /dev/null ; then
 echo -e "ERROR: Failed to set new version!"
 exit 1
fi

# build
echo -e "\nINFO: Doing a build with new version..."
if ! mvn clean package -DskipTests > /dev/null ; then
 echo -e "ERROR: Failed to build with new version!"
 exit 1
fi

# commit to tag
echo -e "\nINFO: Creating tag..."
if ! git add . ; then
 echo -e "ERROR: Failed to git add"
 exit 1
fi
if ! git commit -m "[Project] Set new version ${releaseVersion}" ; then
 echo -e "ERROR: Failed to git commit"
 exit 1
fi
if ! git tag --sign --message "[Project] New Version ${releaseVersion}" ${releaseVersion} ; then
 echo -e "ERROR: Failed to git tag"
 exit 1
fi

# cleanup
echo -e "\nINFO: Cleaning up..."
if ! git checkout release/${releaseVersion} ; then
 echo -e "ERROR: Failed to checkout release branch"
 exit 1
fi
if ! git branch -D temp ; then
 echo -e "ERROR: Failed to delete temp branch"
 exit 1
fi

# git push
echo -e "\nINFO: Release ${releaseVersion} created. Do you want to push to origin? y/n"
read a
if [[ "${a}" == "y" || "${a}" == "Y" ]] ; then
 echo -e "INFO: Pushing to origin..."
 if ! git push origin release/${releaseVersion} ; then
 echo -e "ERROR: Failed to push release branch"
 exit 1
 fi
 if ! git push origin ${releaseVersion} ; then
 echo -e "ERROR: Failed to push tag"
 exit 1
 fi
 echo -e "\nINFO: Pushed release branch and tag for release version ${releaseVersion}"
else
 echo -e "WARN: Release not pushed!"
fi

echo -e "\nINFO: Release ${releaseVersion} created."
echo -e "INFO: Don't forget to update snapshot version!"

exit 0

hotfix.sh: This is the second¬†script to do a hotfix to a release. It’s input is the release version, i.e. 1.0.0 or 1.1.0, and the hotfix version to created i.e. 1.0.1 or 1.1.1. It will check out the release branch i.e. release/1.0.0, create a temp branch to create the tag, create the tag, cleanup and then push to remote:

#!/bin/bash

# usage
if [ $# != 2 ] ; then
 echo -e "Usage: ${0} <release_version> <hotfix_version>"
 exit 1
fi

# Confirm
releaseVersion="${1}"
releaseBranch="release/${1}"
hotfixVersion="${2}"
echo -e "INFO: Do you want to make hotfix version ${hotfixVersion} from release branch ${releaseBranch}? y/n"
read a
if [[ "${a}" != "y" && "${a}" != "Y" ]] ; then
 exit 0;
fi

# validate tag does not exist
echo -e "INFO: Fetching tags and branches and validating they do not exist..."
if ! git fetch --all --tags > /dev/null ; then
 echo -e "ERROR: Tags and branches could not be fetched!"
 exit 1
fi
if git tag | grep ${hotfixVersion} > /dev/null ; then
 echo -e "ERROR: Tag already exists!"
 exit 1
fi

# make sure gpg-agent is available and loaded
echo -e "\nINFO: Searching for gpg-agent..."
if ! which gpg-agent ; then
 echo -e "ERROR: gpg-agent missing!"
fi
if ! gpg-agent 2>&1 | grep "running and available" ; then
 echo -e "WARN: gpg-agent not running, trying to start..."
 if ! gpg-agent --daemon ; then
 echo -e "ERROR: Failed to initialize gpg-agent, please make sure it is up and running before continuing!"
 exit 1
 fi
 if ! gpg-agent 2>&1 | grep "running and available" ; then
 echo -e "ERROR: Failed to initialize gpg-agent, please make sure it is up and running before continuing!"
 exit 1
 fi
fi

# Checkout release branch
echo -e "\nINFO: Checking out release branch ${releaseBranch}"
if ! git checkout ${releaseBranch} ; then
 echo -e "ERROR: Failed to checkout branch ${releaseBranch}"
 exit 1
fi

# create temp branch
echo -e "\nINFO: Creating temp branch..."
if ! git checkout -b temp ; then
 echo -e "ERROR: Failed to create temp branch!"
 exit 1
fi

# set hotfix version
echo -e "\nINFO: Setting version..."
if ! mvn versions:set -DgenerateBackupPoms=false -DnewVersion=${hotfixVersion} > /dev/null ; then
 echo -e "ERROR: Failed to set new version!"
 exit 1
fi

# build
echo -e "\nINFO: Doing a build with new version..."
if ! mvn clean package -DskipTests > /dev/null ; then
 echo -e "ERROR: Failed to build with new version!"
 exit 1
fi

# commit to tag
echo -e "\nINFO: Creating tag..."
if ! git add . ; then
 echo -e "ERROR: Failed to git add"
 exit 1
fi
if ! git commit -m "[Project] Set new version ${hotfixVersion}" ; then
 echo -e "ERROR: Failed to git commit"
 exit 1
fi
if ! git tag --sign --message "[Project] New Version ${hotfixVersion}" ${hotfixVersion} ; then
 echo -e "ERROR: Failed to git tag"
 exit 1
fi

# cleanup
echo -e "\nINFO: Cleaning up..."
if ! git checkout ${releaseBranch} ; then
 echo -e "ERROR: Failed to checkout release branch"
 exit 1
fi
if ! git branch -D temp ; then
 echo -e "ERROR: Failed to delete temp branch"
 exit 1
fi

# git push
echo -e "\nINFO: Hotfix ${hotfixVersion} created. Do you want to push to origin? y/n"
read a
if [[ "${a}" == "y" || "${a}" == "Y" ]] ; then
 echo -e "INFO: Pushing to origin..."
 if ! git push origin ${hotfixVersion} ; then
 echo -e "ERROR: Failed to push tag"
 exit 1
 fi
 echo -e "\nINFO: Pushed hotfix tag ${hotfixVersion}"
else
 echo -e "WARN: Release not pushed!"
fi

echo -e "\nINFO: Hotfix ${hotfixVersion} created."

exit 0

Have fun using the scripts, and don’t hesitate to give me comments!