A linux tool to download files and perform checks, initially thought as a tool to download ISO files

isodl.sh

#!/usr/bin/env bash
# -*- coding: utf-8 -*-

#
# A linux tool to download files and perform checks, initially thought as a tool to download ISO files and
# perform checksums and sign checks.
#
# The config json file is composed as such:
#
# {
#   "downloads": [
#     "http://url/of/file/to/download",
#   ],
#   "checks": [
#     "check_command_to_perform",
#   ]
# }
#
# There is no name mapping
#
# Example:
#
# {
#   "downloads": [
#     "https://downloads.raspberrypi.org/raspios_lite_armhf/images/raspios_lite_armhf-2023-05-03/2023-05-03-raspios-bullseye-armhf-lite.img.xz",
#     "https://downloads.raspberrypi.org/raspios_lite_armhf/images/raspios_lite_armhf-2023-05-03/2023-05-03-raspios-bullseye-armhf-lite.img.xz.sha1",
#     "https://downloads.raspberrypi.org/raspios_lite_armhf/images/raspios_lite_armhf-2023-05-03/2023-05-03-raspios-bullseye-armhf-lite.img.xz.sha256",
#     "https://downloads.raspberrypi.org/raspios_lite_armhf/images/raspios_lite_armhf-2023-05-03/2023-05-03-raspios-bullseye-armhf-lite.img.xz.sig",
#     "https://downloads.raspberrypi.org/raspios_lite_armhf/images/raspios_lite_armhf-2023-05-03/2023-05-03-raspios-bullseye-armhf-lite.info"
#   ],
#   "checks": [
#     "sha1sum -c ./2023-05-03-raspios-bullseye-armhf-lite.img.xz.sha1",
#     "sha256sum -c ./2023-05-03-raspios-bullseye-armhf-lite.img.xz.sha256",
#     "gpg --verify 2023-05-03-raspios-bullseye-armhf-lite.img.xz.sig"
#   ]
# }
#
# This config will download raspios armhf and perform sha1sum, sha256 and gpg check

#
# Copyright (c) 2023 MIQUET Gautier
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions
#
# The above copyright notice and this permission notice shall be included in all
# copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.



# Set the '-u' option to treat unset variables as errors
set -u

ISODL_VERSION="1.0.0"

# Default configuration file
CONFIG_FILE="download.json"

# Function to display script usage
function usage() {
    echo "Usage: isodl [config_file | -h | --help | -v | --version]"
    echo "Description: This script automates the process of downloading files specified in a configuration file,"
    echo "             performing integrity checks, and reporting the results."
    echo "Options:"
    echo "  config_file    JSON Config file to use."
    echo ""
    echo "  -h, --help     Display this usage information and exit."
    echo "  -v, --verison  Display the current version of the program and exit."
    echo ""
}

function version() {
    echo "isodl v$ISODL_VERSION"
}

# Function to download the files
function download() {
    # Loop through downloads and download files
    jq -r '.downloads[]' "$CONFIG_FILE" | while read -r url; do
        filename=$(basename "$url")
        echo ">> Downloading $filename..."

        if ! curl -o "$filename" -fsLOR "$url"; then
            echo "Error downloading $filename"
            exit 1
        fi
    done
}

# Function to perform checks
function check() {
    echo "> Running checks..."

    # Loop through checks and run checks
    jq -r '.checks[]' "$CONFIG_FILE" | while read -r check_command; do
        echo ">> Running: $check_command..."

        if ! eval "$check_command"; then
            return 1
        fi
    done
}

# Check if there are more arguments than necessary
if [ $# -gt 1 ]; then
    usage
    exit 1
fi

# Check if a config file argument is provided
if [ $# -eq 1 ]; then
    if [ "$1" == "-h" ] || [ "$1" == "--help" ]; then
        usage
        exit 0
    fi
    if [ "$1" == "-v" ] || [ "$1" == "--version" ]; then
        version
        exit 0
    fi

    CONFIG_FILE=$1
fi

# Check if the config file exists
if [ ! -f "$CONFIG_FILE" ]; then
  echo "Config file not found: $CONFIG_FILE"
  exit 1
fi

# Process

if ! check; then
    echo "> Initial check failed, downloading files..."

    download

    echo "> Re-running checks..."

    if ! check; then
        echo "! Final checks failed, something went wrong !"
        exit 1
    fi
fi

echo "> OK"