Zero down time deployment script for static generate sites on forge

deploy.sh

#!/bin/bash
set -e

# ./deploy/-deploy.sh
# Deployment with zero downtime
# Based on : https://gist.github.com/actionm/63b927a9b933e54414ae2857e5712162
# By default keeps 2 last deployments in KEEP_DEPLOYMENTS_DIR and current deployment 

usage()
{
   echo ""
   echo "Usage: $0 -b branch -n projectName -d projectDir -k keepDeployments"
   echo -e "\t-b Which git branch to deploy"
   echo -e "\t-n Name of the project"
   echo -e "\t-d Web direcotry"
   echo -e "\t-k How many deployments to keep"
   exit 1 # Exit script after printing help
}

# By default keeps 2 last deployments
keepDeployments=2
branch="master"

while getopts "hb:n:d:k:" opt
do
   case "$opt" in
      b ) branch="$OPTARG" ;;
      n ) projectName="$OPTARG" ;;
      d ) projectDir="$OPTARG" ;;
      k ) keepDeployments="$OPTARG" ;;
      h ) usage ;;
      ? ) usage ;; # Print usage in case parameter is non-existent
   esac
done
 
# Print usage in case parameters are empty
if [ -z "$branch" ] || [ -z "$projectName" ] || [ -z "$projectDir" ] || [ -z "$keepDeployments" ]
then
   echo "Some or all of the parameters are empty";
   usage
fi

##### MAIN
# Branch
BRANCH=$branch
# Project domain
PROJECT_NAME=$projectName
# Project directory
PROJECT_DIR=$projectDir
# History to keep
KEEP_DEPLOYMENTS=$keepDeployments
# Deployments directory
KEEP_DEPLOYMENTS_DIR=/home/forge/deploy

DEPLOY_DIR_NAME=$(date +'%d%m%Y_%H%M%S')
DEPLOY_DIR_PROJECT=${KEEP_DEPLOYMENTS_DIR}/${PROJECT_NAME}
DEPLOY_DIR=${DEPLOY_DIR_PROJECT}/${DEPLOY_DIR_NAME}

echo "Initialize deployment directory '"${DEPLOY_DIR}"'"
[ -d ${DEPLOY_DIR} ] || mkdir -p ${DEPLOY_DIR}

# Importantly retains files outside repo - such as .env
echo "Copying '"${PROJECT_DIR}/"' to '"${DEPLOY_DIR}"'"
rsync -a $PROJECT_DIR/ $DEPLOY_DIR


echo "Execute commands in deployment directory"
cd ${DEPLOY_DIR}

# Update
git pull origin $BRANCH
yarn
yarn generate

# Atomic, zero downtime
echo "Update symlink '"${DEPLOY_DIR}"' to '"${PROJECT_DIR}.tmp"'"
ln -s $DEPLOY_DIR ${PROJECT_DIR}.tmp

# Remove current project directory if not symlink
if [ ! -h $PROJECT_DIR ]; then
  rm -rf $PROJECT_DIR
fi

echo "Update symlink '"${DEPLOY_DIR}.tmp"' to '"${PROJECT_DIR}"'"
mv -Tf $PROJECT_DIR.tmp $PROJECT_DIR

echo "Clear old deployments in '"${DEPLOY_DIR_PROJECT}" keep last '"${KEEP_DEPLOYMENTS}"'"
cd ${DEPLOY_DIR_PROJECT}
rm -rf $(ls ${DEPLOY_DIR_PROJECT} -t | grep -v ${DEPLOY_DIR_NAME} | tail -n +$((KEEP_DEPLOYMENTS+1)))