Installs docker container names and IP addresses in /etc/hosts https://x.com/Celmaun/status/1866434295805456807

docker-etc-hosts-install.sh

#!/usr/bin/env bash
# vim:set ft=bash ts=4 sw=4 et :
# shellcheck shell=bash
# shellcheck disable=SC2317

## Usage:
##   docker-etc-hosts-install
##   Installs docker container names and IP addresses in /etc/hosts
##   This script is idempotent
##   Note: Requires root privileges to write to /etc/hosts
##   Example output written to /etc/hosts:
##       #START_DOCKER_ETC_HOSTS#
##       192.168.97.16    caddy-1.localhost
##       192.168.97.15    www-1.localhost
##       192.168.215.2    portainer.localhost
##       #END_DOCKER_ETC_HOSTS#

set -a

orex() { "$@" || exit "$?$(printf >&2 '^ ERROR[%d]: %s\n' "$?" "$*")"; }
oret() { "$@" || return "$?$(printf >&2 '^ ERROR[%d]: %s\n' "$?" "$*")"; }

sed_inplace() {
  case $(sed --help 2>&1) in
  *GNU*) sed -i "$@" || return ;;
  *) sed -i '' "$@" || return ;;
  esac
}

docker_etc_hosts_file() {
  printf '%s\n' "/etc/hosts"
}

docker_etc_hosts_clear() {
  orex sed_inplace '/#START_DOCKER_ETC_HOSTS#/,/#END_DOCKER_ETC_HOSTS#/d' "$(docker_etc_hosts_file)"
}

docker_etc_hosts_entries() {
  # Docker prefixes container names with a slash
  # First sed is to remove containers with empty IP (slash prefixed lines)
  # Second sed replaces slash prefix in container names with spaces

  printf '%s\n' "#START_DOCKER_ETC_HOSTS#"
  docker ps -a --format "{{.Names}}" |
    xargs -I {} sh -c 'docker inspect -f "{{range .NetworkSettings.Networks}}{{.IPAddress}}{{end}}{{.Name}}.localhost" {}' |
    sed '/^\//d' |
    sed 's@/@    @g'
  printf '%s\n' "#END_DOCKER_ETC_HOSTS#"
}

docker_etc_hosts_install() {
  orex docker_etc_hosts_clear
  docker_etc_hosts_entries >>"$(docker_etc_hosts_file)"
}

set +a

orex docker_etc_hosts_install