Add migration script for Ghost CLI -> Docker installs

- This script handles the copy of both assets and the MySQL database
  from an existing install to a new Docker based install
- Its currently been tested on the "happy path" of a Ghost CLI install
  and works

.github/workflows/shellcheck.yml

@@ -0,0 +1,16 @@
+---
+name: "ShellCheck"
+on:
+  pull_request:
+  push:
+    branches:
+      - main
+
+jobs:
+  shellcheck:
+    name: ShellCheck
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v4
+    - name: Run ShellCheck
+      run: find . -type f -name "*.sh" -exec shellcheck {} +

mysql-init/create-multiple-databases.sh

@@ -6,7 +6,7 @@ set -u
 if [ -n "$MYSQL_MULTIPLE_DATABASES" ]; then
   echo "Creating multiple databases: $MYSQL_MULTIPLE_DATABASES"
 
-  for db in $(echo $MYSQL_MULTIPLE_DATABASES | tr ',' ' '); do
+  for db in $(echo "$MYSQL_MULTIPLE_DATABASES" | tr ',' ' '); do
     echo "Creating database: $db"
     mysql -u root -p"$MYSQL_ROOT_PASSWORD" <<-EOSQL
       CREATE DATABASE IF NOT EXISTS \`$db\`;

scripts/migrate.sh

@@ -0,0 +1,117 @@
+#!/usr/bin/env bash
+
+set -euo pipefail
+
+# Check we're running as root
+if [[ "$EUID" -ne 0 ]]
+then
+    echo "Sorry, this script must be run as root!"
+    exit 1
+fi
+
+echo "WARNING: This script is currently in beta, please ensure you have a backup of your current installation!"
+
+read -rp 'Are you sure you want to continue? (y/n): ' confirm
+
+if [[ "x${confirm}" != "xy" ]]
+then
+    echo "Aborting..."
+    exit 1
+fi
+
+# Check if we have jq installed
+if [[ ! $(which jq) ]]
+then
+    echo "jq is not installed, please install it first"
+    exit 1
+fi
+
+# Prompt for current installation location
+read -rp 'Current installation location: ' current_location
+
+if [[ -z "$current_location" ]]
+then
+    echo "Current installation location is required"
+    exit 1
+fi
+
+# Start some safety checks
+
+# Check whether we can find a Ghost-CLI installation
+if [[ ! -f "${current_location}/.ghost-cli" ]]
+then
+    echo "Could not find a Ghost-CLI installation at ${current_location}"
+    exit 1
+fi
+
+# Check whether we can find a Ghost installation
+if [[ ! -d "${current_location}/content" ]]
+then
+    echo "Could not find a Ghost installation at ${current_location}"
+    exit 1
+fi
+
+if [[ ! -f "${PWD}/.env" ]]
+then
+    echo "Ensure you have a .env file setup for the new installation before continuing"
+    exit 1
+fi
+
+read -rp 'MySQL user to export the current database (must have permission to run mysqldump - defaults to root): ' mysql_user
+mysql_user=${mysql_user:-root}
+
+# Stop current installation
+read -rp 'This script is about to stop the current installation whilst it migrates to the new installation. Are you sure you want to continue? (y/n): ' confirm
+
+if [[ "x${confirm}" != "xy" ]]
+then
+    echo "Aborting..."
+    exit 1
+fi
+
+systemctl stop nginx
+systemctl disable nginx
+
+systemctl stop "ghost_$(jq -r < "${current_location}/.ghost-cli" '.name')"
+systemctl disable "ghost_$(jq -r < "${current_location}/.ghost-cli" '.name')"
+
+# Create new installation directory
+# TODO: Ensure this is safe?
+mkdir -p "${PWD}/data/ghost/"
+
+# Copy current installations content dir
+rsync -qHPva "${current_location}/content/" "${PWD}/data/ghost/"
+
+echo "Fixing user permissions..."
+chown -R 1000:1000 "${PWD}/data/ghost/"
+
+# Starting MySQL container to import the database
+docker compose up db -d
+
+# Dump MySQL database to data dir so we can import it
+echo "This script is about to dump the MySQL database, please enter the MySQL password for ${mysql_user} when prompted"
+mysqldump -u "${mysql_user}" -p --host="$(jq -r < "${current_location}"/config.production.json '.database.connection.host')" "$(jq -r < "${current_location}"/config.production.json '.database.connection.database')" > "$PWD"/data/ghost_import.sql
+
+# We do this _after_ the dump since the user will likely take time to input their password anyway
+# Wait for MySQL container to be ready
+echo "Waiting for new MySQL container to be ready..."
+timeout=120
+counter=0
+until [ "$(docker compose ps db --format json | jq -r '.Health')" = "healthy" ] || [ $counter -eq $timeout ]; do
+    echo -n "."
+    sleep 1
+    ((counter++)) || true
+done
+
+if [ $counter -eq $timeout ]; then
+    echo " Timeout waiting for MySQL to be ready"
+    exit 1
+fi
+
+echo " MySQL is ready!"
+echo "Importing database..."
+docker compose exec -T db sh -c 'exec mysql -uroot -p"$MYSQL_ROOT_PASSWORD" $MYSQL_DATABASE' < "${PWD}/data/ghost_import.sql"
+
+# Starting Ghost container
+echo "Starting Ghost and Caddy containers..."
+docker compose up ghost caddy -d