Add helper script to check minimum requirements

docker/check-requirements

@@ -0,0 +1,112 @@
+#!/bin/bash
+
+set -e -o errexit -o nounset -o pipefail
+
+#
+# Colors
+#
+
+declare -r RED="\e[31m"
+declare -r GREEN="\e[32m"
+declare -r YELLOW="\e[33m"
+declare -r BLUE="\e[34m"
+declare -r NO_COLOR="\e[0m"
+
+#
+# Helper functions
+#
+
+function highlight() {
+    local reset="${2:-$NO_COLOR}"
+    echo "${BLUE}$1${reset}"
+}
+
+function action_start() {
+    echo -en "⚙️ $1: "
+}
+
+function action_start_newline() {
+    action_start "$1"
+    echo
+}
+
+function action_ok() {
+    echo -e "\n\t✅ ${GREEN}${*}${NO_COLOR}\n"
+}
+
+function action_warn() {
+    echo -e "⚠️ ${YELLOW}${*}${NO_COLOR}"
+}
+
+function action_error() {
+    echo -e "\n\t❌ ${RED}${*}${NO_COLOR}" >&2
+}
+
+function action_error_exit() {
+    action_error "${*}\n\n${RED}Aborting!${NO_COLOR}"
+
+    exit 1
+}
+
+#
+# Configuration
+#
+
+declare -r min_docker_compose_version_arr=(2 17)
+min_docker_compose_version=$(
+    IFS=.
+    echo "${min_docker_compose_version[*]}"
+)
+
+#
+# Help text
+#
+
+DOCKER_HELP="
+
+\tWe recommend installing Docker (and Compose) directly from Docker.com instead of your Operation System package registry.
+\tPlease see $(highlight "https://docs.docker.com/engine/install/")${RED} for information on how to install Docker on your system.
+
+\tAlternatively, you can update *JUST* the Compose plugin by following the guide here:
+\t$(highlight "https://docs.docker.com/compose/install/linux/#install-the-plugin-manually")${RED}.
+
+\tLearn more about Docker compose release history here:
+\t$(highlight "https://docs.docker.com/compose/release-notes/")${RED}.${NO_COLOR}"
+declare -r DOCKER_HELP
+
+#
+# System checks
+#
+
+echo -e "👋 ${GREEN}Hello!"
+echo -e ""
+echo -e "This script will check your system for the minimum requirements outlined in the Pixelfed Docker install guide"
+echo -e "You can find the guide here ${BLUE}https://jippi.github.io/pixelfed-docs-next/pr-preview/pr-1/running-pixelfed/docker/prerequisites.html#software${GREEN}."
+echo -e "${NO_COLOR}"
+
+action_start "Checking if [$(highlight "git")] command is available"
+command -v git >/dev/null 2>&1 || { action_error_exit "I require the 'git' command, but it's not installed"; }
+action_ok "git is installed"
+
+action_start "Checking if [$(highlight "docker")] command is available"
+command -v docker >/dev/null 2>&1 || { action_error_exit "I require the 'docker' command, but it's not installed. ${DOCKER_HELP}"; }
+action_ok "docker is installed"
+
+action_start "Checking if [$(highlight "docker compose")] command is available"
+docker compose >/dev/null 2>&1 || { action_error_exit "I require the 'docker compose' command, but it's not installed. ${DOCKER_HELP}"; }
+action_ok "docker compose is installed"
+
+compose_version=$(docker compose version --short)
+
+declare -a compose_version_arr
+IFS="." read -r -a compose_version_arr <<<"$compose_version"
+
+action_start "Checking if [$(highlight "docker compose version")] major version (${min_docker_compose_version_arr[0]}) is acceptable"
+[[ ${compose_version_arr[0]} -eq ${min_docker_compose_version_arr[0]} ]] || { action_error_exit "I require minimum Docker Compose major version ${min_docker_compose_version_arr[0]}.x.x - found ${compose_version}.${DOCKER_HELP}"; }
+action_ok "You're using major version ${compose_version_arr[0]}"
+
+action_start "Checking if [$(highlight "docker compose version")] minor version (${min_docker_compose_version_arr[1]}) is acceptable"
+[[ ${compose_version_arr[1]} -ge ${min_docker_compose_version_arr[1]} ]] || { action_error_exit "I require minimum Docker Compose minor version ${min_docker_compose_version_arr[0]}.${min_docker_compose_version_arr[1]} - found ${compose_version}.${DOCKER_HELP}"; }
+action_ok "You're using minor version ${compose_version_arr[1]}"
+
+echo -e "🎉 ${GREEN}All checks passed, you should be ready to run Pixelfed on this server!${NO_COLOR}"