#!/bin/bash
#
# Shell scripts for get image manifest from v2 registry
#
# Tested on Debian 8, curl 7.38.0, jq-1.5
#

set -e -u

# Default tag is latest
tag=latest

getLogin() {
    read -p "Please enter username: " username
    read -p "Please enter reponame: " repo
    reponame=${username}/${repo}
    if [ -n "$username"  ]; then
        read -s -p "password: " password
        echo
    fi
}

getBearerToken() {
    local HEADERS
    local RESPONSE

    if [ -n "$username"  ]; then
        HEADERS="Authorization: Basic $(echo -n "${username}:${password}" | base64)"
    fi
    echo [+] Logging in
    curl -s -H "$HEADERS" "https://auth.docker.io/token?service=registry.docker.io&scope=repository:${reponame}:pull" | jq '.token' -r > token
    echo [+] Got Bearer token
}

getManifestV2() {
    local ACCEPT="Accept: application/vnd.docker.distribution.manifest.v2+json"
    local REGISTER_URI="https://registry-1.docker.io/v2"
    curl -s -H "${ACCEPT}" -H "Authorization: Bearer $(cat token)" "${REGISTER_URI}/${reponame}/manifests/${tag}" -o manifest.json
    echo
    echo [+] Got Manifest in \`manifest.json\'
}

doClean() {
    rm token
    echo [+] Token file removed
}

getLogin
getBearerToken ${reponame}
getManifestV2
doClean