Docker volume backup and restore function

docker_volume.sh

#!/usr/bin/env bash

ColorOff='\033[0m' # Text Reset
Yellow='\033[0;33m' # Yellow for important info
Red='\033[0;31m' # Red for errors
function infoMessage() {
    echo -e ${Yellow}
    echo $1
    echo -e ${ColorOff}
}
function errMessage() {
    echo -e ${Red}
    echo $1
    echo -e ${ColorOff}
}
errHandler() {
    # Any steps that must be taken prior to exiting due to error
    errMessage "Something went wrong. Exiting now."
    exit 1
}
set -eE # -e throw ERR for any non-zero exit codes, -E as well as in any child functions
trap 'errHandler' ERR INT # Call errHandler function on ERR (non-zero exit code) or INT (ctrl-c interupt execution)

local action=$1
local volume_name=$2
local file_path=$3

if [[ -z $action || -z $volume_name || -z $file_path ]]; then
  infoMessage "Command may be used to backup or restore docker volumes to and from tar.gz files"
  infoMessage "Usage: docker_volume <backup|restore> <volume_name> <file_path>"
  infoMessage "Example: docker_volume backup my_volume_name /path/to/backup_file.tar.gz"
  return 1
fi

# Ensure file_path ends with .tar.gz
if [[ ! "$file_path" =~ \.tar\.gz$ ]]; then
  infoMessage "File path does not end with .tar.gz, adjusting..."
  file_path="${file_path}.tar.gz"
  infoMessage "File path now set as $file_path"
fi

# Check if the volume exists
if ! docker volume inspect "$volume_name" &>/dev/null; then
  errMessage "Volume '$volume_name' does not exist."
  # Try to list similar volume names
  local similar_volumes=$(docker volume ls --format '{{.Name}}' | grep -i "$volume_name" || true)
  if [[ -n "$similar_volumes" ]]; then
    infoMessage "However, similar volume names were found: $similar_volumes"
  else
    infoMessage "No similar volume names were found. Use \`docker volume ls\` to ensure the volume name is correct."
  fi

  if [ "$action" = "backup" ]; then
    return 1
  elif [ "$action" = "restore" ]; then
    infoMessage "Are you sure you want to proceed with restoring to '$volume_name'? [y/N]"
    read -r response
    if [[ ! "$response" =~ ^[yY]([eE][sS])?$ ]]; then
      errMessage "Restore operation aborted."
      return 1
    fi
  fi
fi

case $action in
  backup)
    if [ -f "$file_path" ]; then
      infoMessage "The file $file_path already exists. Overwrite? [y/N]"
      read -r response
      if [[ ! "$response" =~ ^[yY]([eE][sS])?$ ]]; then
        errMessage "Backup operation aborted to prevent overwriting existing file."
        return 1
      fi
    fi
    infoMessage "Starting backup..."
    docker run --rm -v "$volume_name":/volume -v "$(dirname "$file_path")":/backup alpine /bin/sh -c "apk add --no-cache tar > /dev/null && tar czf - -C /volume ./ > /backup/$(basename "$file_path")"
    infoMessage "Volume '$volume_name' has been backed up to '$file_path'"
    ;;
  restore)
    infoMessage "Starting restore..."
    docker run --rm -v "$volume_name":/volume -v "$(dirname "$file_path")":/backup alpine /bin/sh -c "apk add --no-cache tar > /dev/null && tar xzf /backup/$(basename "$file_path") -C /volume"
    infoMessage "Volume '$volume_name' has been restored from '$file_path'"
    ;;
  *)
    errMessage "Invalid action: $action"
    infoMessage "Usage: docker_volume <backup|restore> <volume_name> <file_path>"
    return 1
    ;;
esac