getit

#!/usr/bin/env bash

# A script to download and install the latest Cloudseal alpha.
#
# This will install the following files on the system:
#
#     /usr/cloudseal/
#     /usr/bin/cloudseal -> /usr/cloudseal/bin/cloudseal
#     /usr/bin/cs -> /usr/cloudseal/bin/cs
#
# You can find the latest version of this script at:
#
#     https://cloudseal.io/getit
#
# You may also run this script with:
#
#     curl -sSLf https://cloudseal.io/getit | sudo bash
#
# or to install to a custom location:
#
#     curl -sSLf https://cloudseal.io/getit | bash -s custom_dir
#
# Yes, you're right that running shell scripts off the internet with sudo is
# evil. Don't be lazy and please read through this script before running it.
#
# When packages for each distro are available, please install those instead.

set -Eeou pipefail

TARNAME="cloudseal_alpha_021-858.tbz"
TARURL="https://www.cloudseal.io/s/$TARNAME"

# Default root for the installation
INSTALL_ROOT="${INSTALL_ROOT:-/usr}"
# Fully resolved root:
RESOLVED_ROOT=""

usage() {
    cat 1>&2 <<EOF
A script to download and install the latest Cloudseal alpha.

USAGE:
    getit [--help] [root]

FLAGS:
    -h, --help  Prints help information.

POSITIONAL ARGUMENTS:
    root:       Root of the installation directory. [default: "$INSTALL_ROOT"]
EOF
}

# Create a temporary directory to extract the files to.
TEMPDIR=$(mktemp -d)

# Cleanup after an install
cleanup() {
    echo ":: Cleaning up..."
    rm -rf -- "$TEMPDIR"
}

abort_install() {
    cleanup
    if [ -d "$RESOLVED_ROOT/cloudseal" ]; then
        echo ":: Removing partially installed files, if any."
        if [ -e "$RESOLVED_ROOT/bin/cloudseal" ]; then
            rm "$RESOLVED_ROOT/bin/cloudseal"
        fi
        if [ -e "$RESOLVED_ROOT/cloudseal" ]; then
            rm -rf "$RESOLVED_ROOT/cloudseal"
        fi
    fi
}

# This need not be idempotent as it should only be called once.
handle_exit() {
    local _prev=$?
    if [ "$_prev" != 0 ]; then
      echo ":: Caught error. A command exited with code $_prev"
      abort_install
      echo ":: Install failed due to above errors."
      exit 255
    fi
}

handle_interuption() {
    echo ":: Install script interrupted, cleaning up."
    abort_install
    echo ":: Install failed due to interruption."
    trap - EXIT
    exit 255
}

main() {
    local _positional=()

    for arg in "$@"; do
        case "$arg" in
            -h|--help)
                usage
                exit 0
                ;;
            -*)
                echo "Error: Unknown option '$arg' specified."
                exit 1
                ;;
            *)
                if [[ ${#_positional[*]} -gt 0 ]]; then
                    echo "Error: Too many positional arguments given."
                    exit 1
                fi

                _positional+=("$arg")
                shift
                ;;
        esac
    done

    RESOLVED_ROOT="${_positional[0]:-$INSTALL_ROOT}"
    echo ":: Downloading..."

    # Download and extract to a temporary directory.
    curl -sfSL "$TARURL" | tar -xjf - -C "$TEMPDIR"

    if [ -e "$RESOLVED_ROOT/cloudseal" ]; then
        echo ":: Removing previous Cloudseal installation..."
        rm -rf "$RESOLVED_ROOT/cloudseal"
    fi

    echo ":: Installing to '$RESOLVED_ROOT'..."

    cp -r "$TEMPDIR/cloudseal" "$RESOLVED_ROOT/cloudseal"

    # The determinism-only alpha uses a "cloudseal" CLI.
    mkdir -p -- "$RESOLVED_ROOT/bin"
    ln -sf "../cloudseal/bin/cloudseal" "$RESOLVED_ROOT/bin/cloudseal"
}

# Clean up our mess if anything fails or is interrupted.
trap handle_exit EXIT
trap handle_interuption INT TERM

main "$@"

cleanup
echo ":: Done."