config-repo.sh

#!/bin/bash

set -eu -o pipefail

# Defaults
DOCKER_REPOSITORY=localhost
GITHUB_USERNAME=
IMAGE_NAME="$(basename "$(pwd)" | awk -F'-' '{print $NF}')"
MAINTAINER="$(getent passwd "${USER}" | awk -F':' '{print $5}')"
MAINTAINER="${MAINTAINER:-${USER}}"

#######################################
# Log a message to STDERR and exit with a speific code.
# Globals:
#   None
# Arguments:
#   An exit code
#   A message
# Outputs:
#   A message string is output to STDERR and then exit is called
#   with the specified code.
#######################################
fatal() {
  local exitCode="${1}"; shift
  echo "${@}" 1>&2
  exit "${exitCode}"
}

#######################################
# Print usage information.
# Globals:
#   None
# Arguments:
#   None
# Outputs:
#   A string of usage information to STDERR
#######################################
usage() {
  cat <<USAGE 1>&2
Update Dockerfile, Makefile, and README.md with new values. The Docker image
name is generated by stripping the leading "docker-" from this repository's
directory. Example: if this repository is named "docker-nginx" then the image
name will be "nginx."

Usage: $(basename "${0}") [-h] [-d string] [-i string] [-g string] [-m string]

    -d <string>     Docker repository (default: "${DOCKER_REPOSITORY}")
    -g <string>     GitHub username
    -i <string>     The Docker image name (default: "${IMAGE_NAME}")
    -m <string>     Maintainer string (e.g. "Mark <mark@cdll.me>",
                    default: "${MAINTAINER}")
    -h              This message
USAGE
}

#######################################
# Generate GitHub workflow Markdown badge.
# Globals:
#   None
# Arguments:
#   GitHub username
#   GitHub repository name
#   GitHub workflow name, minus the .yml extension (default: "ci")
#   Git branch name (default: "main")
# Outputs:
#   A string of Markdown
#######################################
github_workflow_badge() {
  local github_username="${1}"; shift
  local github_repo="${1}"; shift
  local workflow_name="${1:-ci}"; shift
  local branch="${1:-main}"; shift
  local url
  local badge_url
  url="https://github.com"
  url+="/${github_username}/${github_repo}"
  url+="/actions/workflows/${workflow_name}.yml"
  badge_url="${url}/badge.svg?branch=${branch}"
  echo "[![CI to Docker Hub](${badge_url})](${url})"
}

#######################################
# Generate Docker image page URL.
# Globals:
#   None
# Arguments:
#   Docker repository name
#   Image name
# Outputs:
#   A string of the Docker image page URL
######################################
docker_image_page() {
  local docker_repo="${1}"; shift
  local image_name="${1}"; shift
  local url
  url="https://hub.docker.com/repository/docker"
  url+="/${docker_repo}/${image_name}"
  echo "${url}"
}

#######################################
# Generate Docker image tags page URL.
# Globals:
#   None
# Arguments:
#   Docker repository name
#   Image name
# Outputs:
#   A string of the Docker image tags page URL
#######################################
docker_image_tags_page() {
  local docker_repo="${1}"; shift
  local image_name="${1}"; shift
  local url
  url="$(docker_image_page "${docker_repo}" "${image_name}")"
  url+="/tags?page=1&ordering=last_updated"
  echo "${url}"
}

#######################################
# Generate Docker image pulls Markdown badge.
# Globals:
#   None
# Arguments:
#   Docker repository name
#   Image name
# Outputs:
#   A string of Markdown
#######################################
docker_pulls_badge() {
  local docker_repo="${1}"; shift
  local image_name="${1}"; shift
  local badge_url
  local url
  badge_url="https://img.shields.io/docker/pulls"
  badge_url+="/${docker_repo}/${image_name}"
  url="$(docker_image_page "${docker_repo}" "${image_name}")"
  echo "[![Docker Pulls](${badge_url})](${url})"
}

#######################################
# Generate Docker image size Markdown badge.
# Globals:
#   None
# Arguments:
#   Docker repository name
#   Image name
# Outputs:
#   A string of Markdown
#######################################
docker_size_badge() {
  local docker_repo="${1}"; shift
  local image_name="${1}"; shift
  local badge_url
  local url
  badge_url="https://img.shields.io/docker/image-size"
  badge_url+="/${docker_repo}/${image_name}"
  badge_url+="/latest?label=latest"
  url="$(docker_image_tags_page "${docker_repo}" "${image_name}")"
  echo "[![Docker Image Size](${badge_url})](${url})"
}

##
# Main
##
while getopts "hd:g:hm:" opt; do
  case ${opt} in
    d) DOCKER_REPOSITORY="${OPTARG}";;
    g) GITHUB_USERNAME="${OPTARG}";;
    h) usage; exit;;
    m) MAINTAINER="${OPTARG}";;
    :) usage; fatal 1 "Option -${OPTARG} requires an argument.";;
    ?) usage; fatal 1 "Unknown option -${OPTARG}.";;
  esac
done

# Dockerfile
# Replace LABEL maintainer=... with the specified value
sed -i "s/LABEL maintainer=.*/LABEL maintainer=\"${MAINTAINER}\"/" Dockerfile

# Makefile
# Replace REPO = ... with the specified value
sed -i "s/REPO = .*/REPO = ${DOCKER_REPOSITORY}/" Makefile

# README.md
# Replace everything between the "Badges" HTML comments
badge_contents="<!-- Badges -->\n"
badge_contents+="$(github_workflow_badge "${GITHUB_USERNAME}" "docker-${IMAGE_NAME}")\n"
badge_contents+="$(docker_pulls_badge "${DOCKER_REPOSITORY}" "${IMAGE_NAME}")\n"
badge_contents+="$(docker_size_badge "${DOCKER_REPOSITORY}" "${IMAGE_NAME}")\n"
badge_contents+="<!-- /Badges -->"
sed -i "/<!-- Badges -->/,/<!-- \/Badges -->/c${badge_contents}" README.md